New addition to the stable X5 35i

[von540i]

Greetings all,
Just purchase a e70 X5. It's a clean, one owner white on black, well optioned (comfort seats, xenon, panaramic roof, rear seats) with 44k mi on it. Drive great as far as I can tell.

I'm looking for some advice on what maintenance items I should be taking care of now, soon and later on down the road. I'm new to the e70 and n55 but not new to BMWs. I have a few (e36, e28,) and had an e53/6speed that I used for years but unfortunately it was time to move on due to age and mileage (270k).

The battery and water pump were just replaced so that's nice but dealer didn't replace the thermostat, so planning for that soon.

Curious what the recommendations are from those who've had them and know them well. If it were you, what would be on your list of "to do's" to make it as road worthy as possible. I've seen recommendations on transmission fluid and filter replacement every 50k. Seems like a pretty short maintenance interval but maybe not for these e70 Bavarian machines. Belt and tensioner are another item that seems to make the list.

What would you do if it were yours?

Thanks in advance!

[andrewwynn]

Crazy nice low miles.

The main issues are there is no way to monitor the coolant pump and when it fails it will only alert you by killing engine power as it overheats.

Get bimmerlink or android equivalent and monitor coolant RPM and oil and coolant pressure.

Oil changes at 7500 is a fairly conservative number.

The oil pump is programmed to put out as little pressure as needed and it's the N55s Achilles heel.

I had to replace my motor when the engine seized at just under 200kmi.

That being said the most important thing to prevent oil starvation is when doing any job that interrupted the oil circuit to do a prime of the oil circuit.

I am directly involved with 4 N55s that spun rod bearings with several different causes.

Mine: boost pressure leaked into the crankcase and interrupted the oil rate going through the rod bearings.

Most likely cause: CCV system check valve failed and let full boost at redline into crankcase.

Engine seized in seconds. Autopsy showed several rod shells welded to the crank and no significant wear to the shells with no glitter in the oil.

Wife's N55 rod bearing failed when OFHG blew out, loss of pressure, most likely when she went to overtake a "fossil driver".

Her engine didn't seize: but a couple bearings stuck to the crank and try tore the hell our of the big end of the con rod. That's actually a good thing. There's a chance the crank survived and i can rebuild that motor cost effectively.

So: no way to really avoid one of those random catastrophe but what is very important: don't use start/stop if you car has it, change oil more frequently of you do lots of city driving, gas gets into the oil and ruins it.

Stay on top of oil leaks, and check occasionally if your vacuum tank built into the head cover has failed. OFHG, replace immediately on the first sign of weeping. The usual issue with that is oil leaks down the front and kills the serpentine belt but far riskier is if the seal fails catastrophically like wife's.

I drove my car like a rental and it pulled like hell every demand up to 200 kmi so look forward to a long life.

The only preventive maintenance other than plugs i can think of coming up is intakes valve walnut blast. Recommended every 30-50,000 mi. Usually never done by the first owner.

Unless you know history, replacing the intake air filters and cabin air filters are usually neglected.

Get bimmerlink mentioned above but also bimmercode. You can set a bunch of things right such as keyfob roll up all the windows, disable the every launch alerts on iDrive, set the welcome lights behavior (i set only white lights all corners for example).

My E70 came with the special lighting interior. I think i have like six or eight more lights i hope you have the same it's mind blowing. My PO replaced all the lights with LED inside and out.

My car's hid lights failed within a couple months. Pay attention to the color of the headlights. If you get any off color at all they are worn out. Most people will wait until the lights are 30-40% loss of brightness without knowing it.

It shouldn't apply to you for years but as the n55 ages/wears the factory settings for oil pressure mapping becomes too low and is most likey the lynchpin of the oil starvation that happens almost always.

In mine and wife's cases, 8-10# more oil psi and catastrophic engine failure would have just been a very messy engine oil puke, low oil warning and maybe reduced power.

I'm working on fix for that and will share the exact fix when I have it.

Get/keep great tires: mine are a compromise that are "very ok" but full throttle shifts will break traction on both 1-2 and 2-3 shifts!

The car is great, enjoy the crap out of it. I'm envious about the low miles! Mine had 144kmi when i bought it.

Oh almost forgot:

Never wide open throttle until oil temp is 60-70C (bimmerlink).

When ambient is very cold, drive in Ds until oil temp is up to maybe 30-40 and turn off HVAC until coolant temp is 70 and the car will preheat 3-4x as fast.

Your transmission is too young it shouldn't have this issue but model of xm in E70 has a common issue add it ages, the torque converter won't grab until 1100-1200 RPM. Should this happen just get used to a soft right foot until it grabs and you can launch very very smoothly.

Oh one more thing: i hated the concept of the electric parking brake until i used it to stop the car. It will brake the car faster than most people ever brake. Try it so you understand how the system works.

Let off the throttle and coast at about 25 mph then pull the p brake button.

Other than the surprising g forces, take note that it won't stay on when your release. In other words it works just like foot brake. It only locks of you are stoped when engaged.

Ok that's it for now.


–awr–

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[von540i]

Thanks for the thorough response.

I didn't know oil starvation was such a prevalent failure mechanism for the n55. I did think it was odd that BMW went away from providing a coolant temperature on the gauge cluster. It's hard to know if/when the engine has warmed up properly with out it. I prefer more information rather than less but I digress. Lucky I don't have the start/stop feature.
I'll have to look into the oil pressure issue... Might be above my pay grade. ?

I like the bimmerlink and bimmercode recommendation... It would be nice to personalize some of these settings like you've mentioned.

Is there anyway to add a dipstick to the engine? I find that somewhat obtuse for BMW to just rely on the digital level gauge, given the significance of getting the oil level wrong.

Do most owners keep the run flat tires or move back to the traditional ones and just roll the dice on tire leaks? I was thinking of replacing with traditional ones and just keep afix-a-flat kit in the trunk if I pickup a nail or screw. Not ideal but considering it. I wish I had the spare my e53 had.

I'll go try the e brake. Curious how that'll play out. I'm pretty old-school so a cable a lever would have been just fine here but I can't stop progress!

Thanks again!

[andrewwynn]

I roll the dice with standard tires even though i prefer ROF they saved my bacon 3 rolled times within 3 years. Now i try to keep a replacement tire on hand and have excellent roadside assistance.

Oil starvation N55 really only becomes a significant issue when you get over 120-150 kmi, however I've seen blown N55s at 110, 120. It usually traces back to dry start up after maintenance butb that only is an issue because of the long term minor wear that builds up from low oil pressure in the first place.

The thing that I've noticed is when i go from WOT to coasting, the oil pressure follows a mapping curve that says no load, drop the psi to minimum. That's exactly when my engine self destructed. Redline shifts though 3 or 4 gears then coast. Psi drops to 25 immediately and that's the problem.

If you don't drive like it's stolen you can probably get 250-300 kmi out of the N55 but as they get old a very small upset can kill the engine.

Wife's engine had 120 kmi, never leaked a drop of oil but OFHG blew out and half a quart or more oil sprayed the whole side of the motor.

Probably during that sameb trip she gunned it to pass somebody and WOT to coasting drops the pressure too low and spun bearing.

Victor SPEED PLUG Kit Tire Repair Plugs & Puller at Menards https://www.menards.com/main/tools/a...7166914220.htm

This is what i use. I've used them about 8 times between my cars, m family and random people with flats on the roadside or in parking lots.

I've looked into getting a thin spare they are nice: same rolling circumference as full size tire but 2/3 the width so fit under the trunk area.

One tire usually wears the fastest so I'll replace tires as a pair if one axle has a lot of tread that leaves me with one tire that has maybe 4-5/32 which is perfect for a backup. I will bring that with on long trips like now when I'm working out of state for a few months. I have a tire i can get mounted if needed.

I've used cable fed parking brakes to stop a car when hydraulics have failed. At BEST they stop 10% as good as E70 P brake. 1000% improvement stopping a car in case of emergency is all i needed to be immediately converted for life.

I've had plenty of hand brake failures to deal with, I live in the rust belt! The annoyance with the P brake is a minor defect is usually inside the no serviceable parts module that is very expensive.

Speaking of very expensive: the gear suggestion knob has a way of the sport mode interlock failing and the only fix is changing the whole thing. It's nearly $1000 part which keeps the second hand marker pretty expensive also. Usually $250-300.

There are a few items like that: fixing a leaky grommet on the washer fluid pump involves removing the whole right front fender.

The fenders make a complete circle around the headlights making minor fender benders a much bigger problem. (also makes changing/repair oi headlights 10x more difficult than e53.

All that said I'm still very happy with my E70 and that says a lot considering i had to replace my engine to keep it!

The N55 is very efficient and too good at heat removal; if you live in a colder climate, put some cardboard in front of half the radiator (not the intercooler) and the engine will warm up 2-4x as fast. The newer cars face have automatic shutters inside the grill that close until the engine warms up. Wife's car has that.

–awr–

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