Fuel Pump Lifespan warning
 

FYI
My fuel pump lasted 226,000 miles. Car just died while driving so about $700 repair with filter.
I cut the fuel filter apart, looked black but not that bad, no large particles. Not sure if it was clogged but does not matter, I was way past due. BMW says lifetime fuel filter but not true.

Change your fuel filter and pump yourself if over 150k miles in my opinion as colder climates harder on pump.
2001 X5 3.0
Arizona

Not a bad idea, I should probably replace my fuel pump and fuel filter since mine are most likely still original at 213k miles.

Mine kicked out at about 195K right after a fillup in cold January weather almost 2 years ago to the day...had it towed to the shop to swap for a new one - thank goodness for the trap door, so I didn't have to sacrifice a whole tank of gas!

To be honest that's pretty awesome life at 200k+

My X is at 93k and based on that lifespan the fuel pump should outlive the car lol

Amazing X fuel pump lasted that long. My M5 fuel pump died on me with only 75k on it

My original E46 fuel pump is at 120K miles and my E53 original pump is at ~97K miles.

They are both on my radar to preemptively replace in this coming year to insure no surprises as a result of this high mileage component.

Mike

Studies show a fuel pump should last 4000-6000 hours. The fuel filter is probably 80-200x as large as "old school filters" so the filter really is lifetime, that said it also is the pressure regulator so not a terrible idea to replace every quarter million miles or so :-)

The pump is not difficult to replace. The siphon pump (left side) has no moving parts save the level measuring float. If the car can drive down to single digit distance to empty, don't need to worry about the left side of the tank.

226,000 miles means average of 45 miles per hour on an average amount of pump hours, not unreasonable if mostly highway miles. I personally wouldn't bother pre-emotive replacement but should my car make 200k (miles) I would maybe buy a pump and keep it real convenient (e.g. In the trunk on a cross country trip). With amazon prime you are only one day (often same day) away from a pump in hand and its not a one hour job to replace the pump.

If you live in the Midwest and are forced to use shitty gas, there is a single actual benefit: alcohol in the fuel greatly increases the lifespan of a fuel pump. Probably 30-80% longer lifespan. (With 20% alcohol it almost eliminated wear)

Amen for the trap door access to the pump! It's straight up brilliant. I built a proper tool to open the pump but you can get away with a screwdriver and hammer in a pinch. It's about 4/10 difficulty to replace the pump.

I replaced wife's at about 131313 miles (guess shouldn't have been surprised at the bad luck). Pump was still working ok-ish just weak and siphon pump wasn't working properly. Actual problem turned out to be a bad o-ring on the siphon pump. See my thread about the gas pump. Her pump would have lasted 10s of 1000s of miles but it didn't bother me a bit that I spent an extra $105 on a decent warrantied off-brand pump. I could tell it was pumping harder based on the test 6 feedback.

If you can get an idea of your average speed you can get a good sense of lifespan by multiplying by average hours.

A fuel pump should last 4000-5000 hours in clean gas, about 6000-8000 hours in polluted (alcohol added) gas. I didn't see an equivalent long term test for diesel pump.

I would estimate an average lifespan of 150,000 to 200,000 miles (30-40 mph average). With that type of range and that it's easier to change the pump than the battery or the thermostat, I wouldn't bother with a preemptive strike, however since the pump will likely "soft fail"; as soon as you see symptoms of a weak pump (can't maintain full power at WOT (wide open throttle) or can't drive down to 10 miles DTE then it's time to replace before it leaves you stranded. I definitely recommend driving down at least to the low fuel light regularly as a soft rail (weak but working) pump will typically show itself by the car stalling with out of fuel (lean no gas) code with 20-30L of gas in the tank.

It would not be too difficult to hook up a tube directly between the two tank hookups to measure the fuel volume the pump can push to get an objective measurement of the strength of the pump rather than guessing. I've seen the gauge that a shop would use and it may be inexpensive enough to own for preventative maintenance.

Thanks OP for the input to the group. Sorry to hear you got stranded the same recently happened to me twice a week apart because the car had a fuel pump problem but *also* a failing CPS so since the codes matched CPS I replaced that first without knowing the fuel pump siphon wasn't working so I got to "run out of gas" with 20% left on the gauge twice in a week.

Interesting posts. Mine went out yesterday at 125K. Along with the alternator mount bracket gasket which causes an oil leak.

Thanks for those estimates on service life.

I'm a fan of not having surprises, so the further away from surprises I can be the better for my service uptime.

Just did a 1200 mile trip and once ran it down to 25 miles DTE, not a comfortable feeling since I had never been in that zone before with my E53. I quickly bought a couple gallons a few miles before my low cost planned fuel stop at Sam's Club in Joplin, MO. Felt a lot better :thumbup:

If I had a little gas can (with 1.5 gallons or so) in the vehicle at the time, I would have been less concerned.

Mike

As preventive maintenance it's quite important to drive down to at least half way into the low fuel light, it's the only way to know the fuel delivery is working properly. The way the x5 works, once below half a tank of gas, it is always using the last 8L of gas and there is no difference in operation down to a about 10 miles DTE e.g. up or down hills, cooling the pump etc, none of the "don't drive less than 1/4 tank" myths apply to an x5: down to about 1/30th of a tank the engine has no idea its low on fuel.

I mostly drive my X5 4.6 around town, so I'm not super concerned about the fuel pump. I generally gas up when the gas light comes on (around 45 miles of range according to the OBC). Now once I set up my X5 to do long distance car towing, then I might want to change the fuel pump preemptively so it doesn't die while I'm towing a car on a trailer in the middle of nowhere.

I've replaced mine (fuel filter/regulator) too at 90k due to a slight hesitation and dropping power at fourth gear.

It fix my revving issue at 2.5k rpm dropping to 1.8k rpm......now it's much more linear and rpm hardly fluctuates.

Keep in mind that these fuel pumps are submersed in fuel to help pkeep them cool during operation. When the tank goes really low often more stress is imposed on the pump.

This does not apply to x5. The pump is submerged until there is little enough fuel you could walk home. Approximately 2L or 1/45 of a tank is enough gas to keep the pump submerged. Once a x5 has less than half a tank it always is using the last two gallons of gas.

If you get below about 10 miles to empty there is some chance the pump will start being exposed to air, that being said, the metal shell of the pump is quite thermally conductive and you can worst case drive 20 minutes or so once fuel would get that low. Simply not long enough to cause a problem.

Running out completely is a different story and the manual specifically mentions don't run out completely.

Think of it like this: you are at a bar drinking beer, but out of a shot glass. You have a full stein next to the shot glass: every time you take a sip, the bartender uses the stein to refill the shot.

The shot is your only source of drink and until the stein is empty you have beer always but just out of a tiny glass.

This is exactly how x5 works. There is a tiny (8L ) tank that is all "the engine" knows about. The main tank refills the tiny tank continuously until it (main tank) is empty.

There is no benefit in "having more than 1/8 of a tank" in an x5 from the engine or fuel delivery standpoint no 1950s myth about gas apply to the x5.

There is a very good reason for this design: the "well" in the fuel tank that is the "surge tank" or reserve tank is very deep and narrow: this is so even if the car is at a 37° angle, the pump will stay submerged even with less than 4-5 L of gas! (In fact if you are nose down pitch at say 30-40°, the car will only "see" perhaps 3-4 L of gas because the rest will have spilled out of the 8L surge tank.

As somebody who's experienced fuel starvation with 1/4 tank of gas from parking on a driveway with maybe 5° or slope I really love this system.

Additional benefits include elimination of grime from the bottom of the tank, there simply is none. After 131,000 miles my wife's x5's tank looked 1 day old.

Water sinks. Any water gets in its the first thing pumped out.

Having recently been stranded SPECIFICALLY BECAUSE my wife was brainwashed to "never go below 1/4 tank".

If the siphon fuel pump (that moves the gas from the main tank to the "shot glass") fails, the engine will starve of fuel with somewhere between 1/8 and 1/2 tank of gas.

Since my wife never ever runs her tank low, it masked the fact her fuel pump was failing and left me stranded "with 77 miles to go".

It's important you periodically (I would do it at least quarterly) run the tank down to the low fuel light it's the only way you can verify the siphon pump is working lest you suddenly go from 450-500 mile range to 350-400 miles of range (with no warning).

I wrote the most detailed write up available online on how the x5 fuel delivery system works recently. I plan to add some graphics to describe the system better soon.

450-500 miles of range? Man, what are you driving? I'm lucky to see 300-350 miles of range in average driving, but then again I have a 4.6 that averages around 13-14mpg.

Highway miles highway miles. I can get 21-22 with mine and 23-24 with wife's (typically 15/17 on mixed use)

Fuel pump failed or transfer pump failed? Seems more like the transfer pump failed to fill the shot glass.

:bustingup

Yeah the 3.0L on the highway gets nicer MPG than the V8s. On a good day my 4.4L can deliver about 400 miles on the highway doing steady 75-80mph.

Great insight on the fuel delivery system. I appreciate it. :thumbup:

Mike

Replace the fuel pump and filter on my "iS" at around 125k miles.

Both as it turned out. Soft fail of electric pump but probably would have gotten me from 70-80 DTE fuel starvation down to 20-30. I found a faulty o-ring in the transfer pump connection:

https://uploads.tapatalk-cdn.com/201...cb7542b398.jpg

And then also the connection below that which has no o-ring from the factory was leaking like a shower so I added in my own design to seal that.

Now I can use all the gas in my tank. I still haven't figured out if the reserve tank is included in the DTE and from test 6 it seems like it is not. Case in point :

At 34 miles DTE the car was reporting about 9.5L on the left side of the tank. That would mean there would be closer to 18L of gas. That should get me closer to 70-80 miles.

I will be opening up the tank to find out the definitive answer soon

Simple troubleshooting. Hook up a fuel pressure gauge and check for variance, low pressure. and if the pressure backs off to quickly or too much when engine is turned off. Can be rented with rent returned when gauge is returned at many auto parts stores. Not that expensive to buy either.

Here's a data point:

2001 E53 3.0i

Fuel pump failed at 173k miles. Luckily it was literally parked in front of my house when this happened.

I took the pump apart to see exactly what happened. The pump looked to be in great shape except that one of the brushes had worn down to exactly (of course) the point where it lost contact with the slip ring. Had this been another type of motor, I think replacing the brushes would have brought it almost back to new. But of course being immersed in fuel and fuel vapors makes that not such a good idea in this case.

It turned out to be pretty convenient for me to fix this, since it died in front of my house. But I'd recommend pre-emptively replacing at 150k if you're sure it is original. On my car, without having a complete set of service records, I was not sure it was original until I removed it.

Fuel Pump Lifespan warning
 

I would not recommend against 150k (mi) preemptive strike. I'm pretty confident you could get some solid objective feedback with gas pressure gauge under WOT. I plan to do some testing on my car since I'm nearing 150k miles and just replaced wife's pump at 132k

Those replacing parts because they might break are likely to become a part of the group that post how expensive X5s are to maintain.

Life cycles of parts vary dramatically. I'm hard pressed to think of anything I have replaced before it broke. I have never carried a part around or kept it in my garage for any daily driver.

I don't fault anyone that does otherwise but new folks need to know you can get along fine by taking the position if it ain't broke don't fix it rather than if it ain't broke it will soon.

Exactly what I was told. thumbup:

(Submerged for cooling)

Though true, the x5 pump will be submerged fully until you are below 10-15 miles to empty. It appears actually that the dashboard DTE doesn't even include most of the surge tank.

(Wife's car, when surge tank is overflowing to the main tank, shows 1.4L on the test six. If the tank is 8L that leaves 6.6L when the tank reads 0.0L total. (Meaning you can likely drive another 20-30 mi. past 0mi. DTE.

Anybody able to chime in with real world example of how many miles past 0 DTE the x5 can actually drive?

I plan to drive my just fixed x5 down to zero (with can of gas in the trunk of course), then open the tank and see how much is in the surge tank.

I've driven my E53 down to the point of lean misfire several times, just over 20 miles after the DTE displays "0".

I'm still on the OE pump (over 200k miles), even running the DTE below 10 miles before almost every fill up (almost 25 gals).

I think the 10 oz of Lucas UCL/fuel system conditioner added at every fill up has helped pump life.

I know that I never fill up until the readout constantly reads 12-14 miles before I run out. At 117,000 miles, still running the original fuel pump, if it dies, my opinion will be that it died of old age, having lived a long, giving and 93 octane life,

Thank you so much for that feedback! That means the reserve tank they call sometimes the surge tank is NOT included in the fuel quantity measurements. (Which is exactly as I anticipated) since the surge tank always has the same level once below about half a tank, and that isn't measured as zero but 1.4L in my case.

I plan to measure the volume of the reserve tank exactly when either DTE is zero and/or when the test 6 shows 0.0 total.

Are you diesel? Gas? And do you use polluted gas (ethanol diluted)? Ethanol greatly reduces commutator wear, possibly doubling the lifespan.

What's your average mpg on a tank and what kind of range?

I would be willing to bet that the conditioner has added 50-100,000 miles if there is any ingredient to lubricate the commutator.

If driven mostly highway miles, and average 50mph, the low end of life expectancy is 200,000 miles (4000 hours). With E10 gas it would be more like 300,000 miles (6000 hours).

Everybody should look at your average of average mpg over a few tanks.

My average speed is about 22-25 mph. That works out to 132,000 to 150,000 life expectancy. That's pretty amazing: my wife's car I just replaced fuel pump at 132,000.

The alternator has a very similar wear pattern with the fuel pump. I just ordered replacement brushes and slip ring kit to refurbish for $20 vs replace for $325. (DIY): pro replacement of alternator ranges from $500-1100.

If you have pure gas use 4000 hours and with E10 polluted gas, use 5000 to 6000 hours expected lifespan. That should give you a very good idea of when to replace in a preemptive strike. (Of course measuring pressure or DTE won't get down to zero, time to replace)

I would replace electric pump first. Even in my case where pump was running ok and turned out to be siphon pump was the main problem, the pump was weak, amplifying the problem. I could maybe get to 70-80 DTE before replacing the fuel pump and down to 40-50 once I did replace the pump.

Now I'm confident I can get to -30 miles DTE with the 6.6L of gas that isn't measured.

In case anybody missed it: apparently when the computer measures 0.0L remaining there still will be more than a gallon of gas putting the pump several inches below the surface meaning there is no benefit to help the engine or fuel pump all the way down to 0 miles DTE.

I will confirm visually when I get Lumba2 (car's name)! Down to either 0L gas reported or 0 miles DTE whichever comes first.

My philosophy on filing up is to maximize range. If you fill up at 1/4 the only benefit is if you are in a hurry you won't have to stop for gas for a reasonably short trip.

Not worth it in my opinion to lop 100 miles off the range.

In 100,000 miles the "fill at 1/4" mindset means 77 additional gas stops. "Ain't nobody got time for that".

It also drops your range from 530 to 390 miles every time. (Hwy miles 3.0 engine).

Now that I understand how the fuel supply on x5 works I'm very happy it is designed quite specifically to run down to zero DTE with no extra wear and tear on the parts.

I start looking for gas only once the low fuel light comes on, the ONLY time that has EVER been a problem was literally CAUSED by my wife always filling up at 1/4 tank and camouflaging the fact the fuel pump/s weren't working.

It actually cascaded into me being stranded with 70-80 miles DTE TWICE in one week, specifically and ONLY because she used the fill at a quarter rule with no objective reasons behind it. Anybody sorta understand why it bugs me that people irrationally have a fear of driving a car with less than 100 miles (and actually 120) to go?

If there was a fact based not mythical irrational fear behind the concept I'd be on board. There really is no objective reason to put gas in before the low fuel light comes on unless you live more than 20miles from nearest gas station.

(Naturally there are exceptions to the rule such as filling up before going on 400 mile trip so you don't need to stop on the way, that's not the meaning behind don't fill up at 1/4) that's not the discussion: it's whether or not to never dip below 1/4 tank. There are no objective reasons for that belief with the x5.

Came here to say I should have preemptively changed my fuel pump. '04 3.0i with 195K mi died tonight, on Christmas Eve, with three people in the car, at an intersection, in a snow storm, 20ºF outside. I kept telling myself "eh, it'll last" until it didn't and the pump went out literally at the worst possible time. Temps plunged today and I think the cold got it.

My advice after 15 years of BMW ownership: add it to regular maintenance around 150K mi.

Good judgement comes from experience and experience comes from bad judgment.

I’ve changed my in tank fuel pump about 4K miles ago at about 122k miles. Watch out for infant mortality of parts also, that can take you out of the fight just as easily.

Mike

It's time not miles. Do a little math. Mine was still going strong at 180,000 miles wife's died at 133,000.

With e10 polluted gas, the average life span is about 6000 hours: 180/6=30 mph, 133/6=22.167. Those were very close to the average mph of mine and wife's cars.

Let your trip computer spin for a month or three without resetting the average mph. Multiply that number by 6000 and get the estimated odometer lifespan.

If you're lucky enough to use non crappy gas, that will last 5000 hours vs. 6000.

Ive had one go bad in a bmw ever.


Wifes died at 250k miles. Wouldnt have died then if she wouldnt run it low on gas all the time.


The other bmw's never see less than 1/4 tank.


The 323i has over 400k on the original pump and still working great.


The rest of them all have the original pumps with over 200k on them except the 2013 which has 80somethingk on it.

200/6=33.333 mph average. If you drive a lot of highway miles it will not be hard to achieve 250-300,000 miles.

On an X5 the "more than 1/4 tank" has no bearing whatsoever on fuel pump wear and actually greatly increases your chance of getting stranded due to the more likely failure of the siphon jet.

The X5 fuel tank sump holds about 5.0L of fuel that's it. Any more spills over to the left side of the tank once you are below about 27L ( well above 1/4).

On other cars even BMW models that have a design to encourage gas to stay near the pump do not have the actual sump like x5 tanks just a skirt around the pump to keep gas from sloshing to the sides during turns.

Pumps no matter how well treated have brushes that slowly wear out and will last 5-6000 hours on average. (with e-10 gas; 4-5000 hours with e-0 unpolluted gas).

I'm not against picking up a replacement pump in the 150-180,000 mile range but it's one of the easiest repairs to perform I would wait for failure or at least until you get over 5000 hours estimated on the pump before replacing.

Unless wife actually ran the pump dry, the whole 1/4 tank thing is a myth from the 50s and 60s.

250/5=50 250/6=41.667. if wife's average speed is between 41 and 50, 250k miles is the expected life of a fuel pump.

At 400k, 400/6=66.667 means almost exclusively highway miles: a pump that age is going to be almost out of brushes and bordering on miraculous. (unless you run e85); apparently more ethanol adds lifespan.

You don't live in an alternate reality where you can treat a pump nicer and get the brushes to not wear. The pump is running 100% of the time that the engine is on it doesn't matter the speed etc.

That said just like the E10 will improve lifespan, you might be using gas with another additive that will add even more lifespan but it will not double the life. I'm sure there are outlier that will last 8000 or even 9000 hours as a fluke that's why I don't recommend preemptive replacement

On the low fuel part your thinking of the oh its got an 1/8th left or so.


Im talking nothing showing on the gauge most of the time. Even with the sump its going to run dry at times. Ive had to push the thing to the pump for her before because she ran it OUT of gas at the GAS station.


I cannot fathom why she thinks it takes more effort to keep it full and never let it get under a 1/4 vs praying you get to the gas station and having to schedule what time she leaves for work so she can get gas.


As for the 323i, yep it will run out of brushes eventually but since its more or less a toy now and isnt used anymore Im more interested in seeing how far it will go now :)


Need to sell it but its more trouble than its worth to try to sell it around here. Paints fading but otherwise its mint.

Also only had one failure over 15+ Bimmers. I agree with Andrew in that the replacement is so easy, unless planning an out of town trip, preemptive replacement is not necessary. Now, if over 150k and going out of town, might replace it to eliminate the worry.

So what was the reasoning behind this myth?


With my diesel Ford truck it has been said that letting the fuel supply get below 1/4 tank increases the chance of getting air into the fuel system that can damage the fuel injectors.


Outside of my diesel truck mentioned above the only reasoning I've heard for not letting the fuel get close to E is to prevent debris from the bottom of the tank getting sucked up. Not sure how much debris the average tank has in it but perhaps this was based on metal tanks rusting?

In the 50s and 60s the problem was dirt and lack of cooling would cause faster damage.

Modern cars have tank/pump design that will keep the pump foot submerged well below 1/4 tank, the X5 to extreme. The pump will be completely submerged until there is less than a gallon of gas left no matter the pitch or roll of the car.

You can drive up a 20° incline with the tank reading 0.0 miles to empty. (when tank reads empty there is still 3.6 liters of fuel).

It's worth looking into how each car fuel supply works. The X5 is a very special case that doesn't require any fuel before the low fuel light comes on.

It does have a design defect that requires looking into where an o-ring will fail in the siphon jet and will cause fuel starvation at about 1/3 to 1/4 tank of fuel.

That situation should be occasionally tested, I suggest at least 1-3x per year, drive down to 10 miles to empty or so to confirm the siphon jet is working.

Best to have the obc hidden menu six running. If the right tank drops to zero before the left tank does indicates the siphon jet is not working properly. If the right side (which should read about 1.4L for the last 1/3 ), ever drops to below one liter, immediately stop the test and get gas, then fix the o-ring on the siphon jet.

At 160-190,000 miles our trucks had less than 1/10g estimated dirt at the bottom of the tank. One I didn't bother to clean out one I siphoned dry so I could weigh and get exact amount of fuel the sump holds. (5.0L: 1.4L shows on the gauge, 3.6L reserve below the zero on the dash gauge).

The reasoning for keeping > 1/4 tank doesn't apply at all to the e53. I was stranded twice on the freeway due to my wife's never letting tank get below 1/4 which allows the blown siphon o-ring go undiagnosed until you need the last quarter tank and you can't use it anymore.

Get a pump put in the trunk. You can change with very basic tools (I even have thumb screw hose clamps). The BMW tool kit with the spare will include a 10mm and in emergency a tire iron and a rock will remove the tank top ring. I would still not replace at an arbitrary age or miles though 150 k miles would be an ok choice for somebody wanting to do so.

I could likely help you with that. Simple math and a resistor will make the low fuel light come on wherever we want. My car has the opposite problem right now a little too much resistance so it reports an extra 7L about ONE liter left when the low fuel light comes on.

1/4 gal = 3.75 miles from low fuel light to empty. Uncool.


I have to swap out my sensor and could tweak to make it read low 7-10L so when low light comes on there is 20 vs. 8 liters and at zero DTE maybe 40 miles. Would be an easy mod.

I hear you. I carry a tool set with me in the cars above and beyond the BMW set. But with these pumps being so cheap and easy to replace. I'd rather do it at home on my schedule before a trip than take an extra pump and do it in an hour on the side of the road. Just my way of thinking, either way works obviously.

Your info regarding the fuel system on the X5 is nothing short of reverse engineering it. Hans and Frans would be proud. :thumbup::D

The problem with preemptive relplace is that you may just install a pump that has 3000 miles of life. My first replacement pump lasted 10 months (replaced under warranty still going). I bought a branded Bosch to replace the other car's much older one at about 185k miles, and when I went to install was DOA. Aaaaghhh. So I would recommend a spare that you plug in once before putting in the trunk :-).

Why not replace the suction jet pump preemptively? If all that fails in that is the O-ring?

Did you ever test that spare pump that I sold you?

Another data point - my fuel pump failed today at 131k miles. Bought a Delphi replacement -only one in stock on a Sunday - started right up, so I'm relieved.

Easy job to install...

No but soon! My left side sender is over zealous and reports an extra 7L so I'm going to be swapping the resistor element from that soon and while I have the back seat off and the convenience of the power plug for right side I'll plug it in and test it out.

What is your dashboard average speed? Will be very interesting to see a rough estimate of hours.

131/6=21.833 or 131/5=26.2. If the EPA tests of 5-6,000 hours address correct your average speed should be in that range.

My wife's feel pump died at right about 131k miles but was a soccer mom car for most of its life so 23-4 mph would be a very likely number.

How do I check average speed? Is it one of the standard displays? Or a "hidden" one?

All that usually fails on the siphon jet is the o-ring and the joint that has no seal. I recommend fixing before about 12-15 years. I had to fix both our X5 siphon o-ring at about 17 years.

Tap the left stalk button it rotates around from temp to mpg mph etc.

Another data for the archive, fuelpump went out at 133.000miles. 2005 3.0i

Fuel Pump Lifespan warning
 

Average mph?

22.167 to 26.6 would put you right in the expected lifetime of E10 gas.

One of our cars pump died at about 133k and one over 170k miles

28 so really close!

So using the hour range from the EPA study, 28*5500=15400 so I'm betting the longer term average is a little less but definitely in the ballpark of the natural curve. I would definitely recommend for people to have a spare in their trunk by 5500 hours. A very through test I think was by the EPA established expected MTBF of 5-6000 hours for e10 gas. It possibly was 4000 pure gas 5000 e10 and 6000 e20. It was 2-3 years since I read that report.

Yes it makes sense. Actually I've read your estimate about a year ago so when the engine suddenly stalled few days ago, I already knew what I should look for. Turning the key and missing the tipical noise of the pump made it quite easy also.

But for the spare pump in the trunk... how do you want to get the pump in and out the plastic housing of the sending unit without some special tool and a decent workbench.

Ok, you can get the pump out of it's housing with some screw drivers and a second pair of hands pushing the release tabs. But how do you manage to put the new pump back in the plastic housing out on the street? It took me a while to find a matching tool in my workshop that would allow me to push the pump in place.


And I don't want to speak about getting the hose of from the old fuel pump. There was no way to getting it of in a normal way. At the end I had to destroy the attachment on the old pump by squeezing it and remove the shattered pieces from the hose afterwards with some patience.

All this out on the street, maybe in the dark...not a option in my mind.


If I would want to carry a spare pump, I would definitely just carry the complete assembly.

Obviously the complete assembly is ideal but just a couple tools similar to a bike tire change kit that would let you change the metal pump only.

You could cut tabs and use zip ties to replace the pump easier and in a pinch a screwdriver and rock you can remove the metal ring.

I use thumb screw hose clamps when assembling fuel pump.

KEEP IN MIND that the Fuel Pump lasts even longer when you dont let the fuel tank go below the middle point So it doesnt gag on air.

100K Miles Clean the fuel tank on the Inside & clean the sensor reader on the pump with an elastic so the Tank Capacity gauge will not get stuck... ever!

Aswell as fill up only with premium (Fuel Filter is due every 30K No matter what BMW Says)

Fuel Pump Lifespan warning
 

The concept of don't go lower than xxx does not apply in the least to the e53 platform.

The pump sits at the bottom of a 5L well. The fuel gauge hits 0.0 with nearly a gallon of fuel left.

If the siphon jet is working the pump knows no difference between 27L and 1.5L remaining on the gauge. That argument is absolutely incorrect (for the e53: I've "run out of gas" with almost 1/4 tank with my Ford explorer when parking on a hill!

100k clean the tank ; iffy- I would wait for the pump to fail (typically between 130-160,000 miles). Our two X5s had maybe 0.2g of dirt at the bottom of the tank at 130,000 ish. Most dirt will be dissolved in the gas and removed by the filter.

The filter and pump won't care in the least about octane but the engine will. The filter is gigantic; maybe 200-300x the size of yesteryear. The filter element is probably good for 300-400,000 miles: yes, really. However the weak link is the o-ring that seals the FPR to the filter and that gave up the ghost at about 180,000 on wife's.

I would say that depending if you have/use a performance model, 100,000 is probably a good time to replace the FPR/filter. 30,000 is way too early.

The tip of cleaning the resistive bar on the level sensor is very keen but no guarantee on "ever" I refurbished mine including the BMW TSB to increase the spring tension and about a year later or reads 7L high: that's sucky.

Mine lasted till 162,000 miles
Arizona
replaced fuel filter at same time.

this year the fuel level sending unit (drivers side) acted up and the tank gauge did not move. Filled it up and after a few days it worked again. Have the part just waiting for it to happen again to replace. Kinda a pain.