Here's a quiz for you DIY'ers

[B-M-W]

Originally Posted by X5only

I follow you SlickGT1. 1.4 cap is my next "upgrade" for both my X5 and E39. I've read about 1.4 cap in the E39 forums but I think your explanation makes a lot of sense. Coupled with that, I recall one time my daughter, who is a senior in Electrical Engineering, pointing out to me that they had a discussion at school wherein the gist of the conversation was products are deliberately designed to fail. She called it something like "planned obsolescence". It happens where engineering meets capitalism. Products aren’t designed to last, so the brightest and most successful engineers don’t aim to create the best possible machine. They aim for maximum profit through steady sales. In other words, our Bimmers aren't the "Ultimate Driving Machine" after all

This is like a conspiracy therory here.

Let me clear something up, it would cost a manufacture MORE money to produce parts that deliberately fail. I work in a manufacturer setting and have been for some time. It just doesn't work this way. You guys that think bmw made a faulty part on porpose have never worked in a manufacture setting with engineers designing, with the other part of the company producing what was engineered. These company's are trying to beat the compition and you think designing faulty parts is a way to win......omg

Slick now you just stated that your research was indeed "a bunch of shit on the forums" right after BC and I explained how you are only going to read the bad. Find me an example of a guy who got 200k out of his cooling system. You won't because he's one of the serval million bmw drivers without cooling issues that are not posting on forums.

Well said BC.

[SlickGT1]

Originally Posted by B-M-W

This is like a conspiracy therory here.

Let me clear something up, it would cost a manufacture MORE money to produce parts that deliberately fail. I work in a manufacturer setting and have been for some time. It just doesn't work this way. You guys that think bmw made a faulty part on porpose have never worked in a manufacture setting with engineers designing, with the other part of the company producing what was engineered. These company's are trying to beat the compition and you think designing faulty parts is a way to win......omg

Slick now you just stated that your research was indeed "a bunch of shit on the forums" right after BC and I explained how you are only going to read the bad. Find me an example of a guy who got 200k out of his cooling system. You won't because he's one of the serval million bmw drivers without cooling issues that are not posting on forums.

Well said BC.

Listen guy. Find another thread. This point on I'm just going to ignore your ass. You have provided nothing but shitty interpretation of every fucking word to your liking without adding anything to the discussion. You clearly need to get the last word in. Go ahead. Simple as that. Open up Google and do some research. Even simpler than that, follow the links I provided for your lazy ass. There are people attaching gauges to their cooling system on the e39 forum. All you are doing is trying add your 2 pennies of nonsense.

Only thing going your way in this thread is the cool aid you drank when you bought your whatever car. Don't preach shit to me. I guarantee you every item on mine is bought from dealer. Your research is shit, there is none of it. Find me a case where a lower bar cap has failed anyone and I will remove you from my ignore list. Adult discussion over. I entertained your ass long enough.

[X5only]

Originally Posted by B-M-W

This is like a conspiracy therory here.

Let me clear something up, it would cost a manufacture MORE money to produce parts that deliberately fail. I work in a manufacturer setting and have been for some time. It just doesn't work this way. You guys that think bmw made a faulty part on porpose have never worked in a manufacture setting with engineers designing, with the other part of the company producing what was engineered. These company's are trying to beat the compition and you think designing faulty parts is a way to win......omg

........

Conspiracy theory? Hmph, sounds like you're lacking in the perspective of the bigger picture here. In fact, the European Union is currently beginning to address this problem. Here's some reading for ya, and read it in its entirety, not just the first few lines:

https://en.wikipedia.org/wiki/Planned_obsolescence

[bcredliner]

Originally Posted by SlickGT1

Lol. I'm not here to convince anyone that my theory and logical conclusion is to make people switch.

I'm not the only one saying this. You know there are forums where there are shit load of other BMW owner who went this route. I'm not the creator of this. I'm actually conservative. People just go for the 1.2 bar cap from GAS. I have the e30 1.4 cap. It's identical by the way. People with 1.2 bar caps actually burp sometimes. Mostly when overfilled. I'm sure those people would rather burp a few ounces instead of dumping a few gallons. Suddenly people have cooling components last longer.

All I am saying there is no reason to be concerned with having a 1.4 bar cap if people want a piece of mind. Because sure as shit a 2.0 cap is not the weakest point.

And yes kvc. New BMW cooling systems are now with reasonable pressures. 1.2 -1.4 bars.

I'm also only offering my opinion, not saying you are wrong. I'm certainly not Dr. cooling system. I'm sure you know the ratings of the current pressure cap used or an E30 is not necessarily evidence that it works on E53s. Or even if that is the solution on a 2002 4.4 it is not necessarily the solution on a 4.6 of the same year or 2003 4.4. Only saying it is important to dissect the input before drawing a conclusion contrary to BMW specs. Your input is still a valid consideration and could be absolutely the best route to go and, yes, others have gone that route.

if I was experiencing failing expansion tanks at less miles than my expectations I would want to find a solution though I would be suspicious and checking that something else was the root cause and the tank was a symptom. If nothing was amiss, I wouldn't be concerned if I was getting a 50,000 mile life from an expansion tank. Generalizing (very dangerous) that would be 4 years at 15,000 miles a year and a relatively inexpensive cost and easy DIY. Besides, new parts are my drug of choice.

[SlickGT1]

I'm saying. No one else finds it odd that people recommend replacing all hoses, tank, radiator, and coolant when your expansion tank breaks? I don't replace one hose and guess what happens.

Oh and I drive in NYC almost daily. AC on. The most ridiculous traffic ever. It took me 45 min to drive Lincoln tunnel to nyu hospital. .3 miles. Just throwing that out there as far as harsh driving environment and zero issues with e30 cap.

I think x5only. You split your tank because of improper mix. Possibly too much water. Boiling point too low, and you stressed out your tank. The real weak point. The cap would have saved your tank. It would have vented, and you would have seen it, and smelt it.

Back in the day (most likely even now), racers, track guys, would remove antifreeze (some tracks won't allow antifreeze), fill 100% water and water wetter. This would lower boiling point. So those guys would need a high pressure "race" cap. This would increase boiling point, and let the water survive the event. When said racers got the cap, it usually went from something like 1.1 bar, to 1.3 bar. Yea. That's it. Because beyond that, you blew cooling components up.

[B-M-W]

Thanks pal

[StephenVA]

IMHO I think most of what you are discussing here is correct.

Too High pressure equals failure of components. Too low of running cooling system pressure settings, equal poor cooling. BMW cooling systems are poorly engineered since the German Gov Greens got their way in regulating recycling percentages of vehicles. Resins, polymers (plastic) will fail in shorter heat/cold cycling rates than most metals. The engineering team has a better track record on later models. New resins? Who knows.

Totally new cooling system parts (OE) with operational corresponding engine and cooling fans, will provide 60,000 mile and beyond drive cycles and not fail. Pressure testing of caps will show degrading over time and should be replaced with cooling system repairs.

Ten plus year ago they made our cars. Improvements in the auto world has been going on long since our models ended. BMW Engineering stopped back in the first year or so and shifted to the next model with the exception of the V8 applications.

Solution: So who is going to pressure test and heat cycle a new OE tank, hoses, connectors, expansion tank, and rad to confirm burst point?
My bet is on a 1970-1980's metal one will last longer, but call me old fashion as I know first hand that the right resin/polymers can produce parts that will exceed metal pressure rates at same weight. Rads with plastic side tanks and rubber seals will leak at 80,000 drive cycle. The American vehicles have the same failure rate on these style Rads. They split and drip all day long.

I am also sure the low bidder won the expansion tank business from BMW on our cars....

[kvc]

I hear what some of you are saying in regard to 'planned obsolescence' and the like. I also think that there's a degree of logic behind the theory of using a 'lower pressure than OEM' cap (i.e. 1.4 bar). Yes, I'm sure there were gurus who designed the cooling system of our cars, and full credit to them. At the end of the day though, we are all only human and therein lies the problem - we are not perfect and auto manufacturers have been known to make mistakes. Yes - there's truth to the argument that many members of these forums will only post when they have problems and rarely, if ever, report trouble-free ownership. That said, what harm can you do by using a 1.4 bar cap I wonder? I personally believe that you can probably do your system more good by providing a more accessible 'weak' point, and one that's designed to 'vent', as opposed to venting via a hose or fitting in a hard to access area (or one that fails causing large loss of coolant)...
I suppose it would be fair to say that my vehicle has now traveled 134,000 km's and I can only assume that the cooling system has worked faultlessly for the previous owner/s (2 of them). Service records indicate that 8 months ago (3 months prior to me buying) the cooling system was flushed and replenished and it's worked well for me all winter long. That said, it's now the beginning of summer, I live in a fairly remote area, devoid of mobile phone reception and a good 1/2 hour or more to the next 'town' (pop. 350), so I need to do what I can to ensure I don't find myself stranded on the side of the road for hours before the next vehicle comes along. In this regard, I believe that it makes good sense to undertake preventative maintenance where I'm able to and can reasonably anticipate possible failure or possible 'design faults'.
The theory put forward by slick, and his (and others') personal experiences in regard to the cooling system, just makes logical sense to me. But that's just me - not necessarily anyone else. I don't see the need to put such a high pressure relief valve (2.0 bar) on a system that may not require it, and possibly place undue stress on other components in that system, unnecessarily. At the end of the day, I suppose you could drive all day long with no cap on, if that's what you like; but the cap is there to provide you with a higher boiling point than 100*C or whatever it is in F (212*?). If the newer model X5's and X6's don't have a 2.0 bar pressure cap (and other BMW's) there must be good reason. Moreover, as stated previously, not one of our other vehicles has a radiator cap or over-flow (expansion bottle) cap with pressure relief greater than 1.5 bar, so unless the E53 has some unique need for a 2.0 bar cap (which I somehow doubt very much) I would be inclined to believe this is unnecessary, possible 'over-kill' and one of those so called 'planned obsolescence' scenarios - (read 'design fault'). As many others have attested to, there are quite a few so called 'design faults' in our vehicles, so there's good argument that this is probably just another one that BMW has since rectified in later models.

[bcredliner]

The key to the premise that a 1.4 bar is the answer is an assumption without verification. That can be as much or greater risk than the concern related to the stock cap. It's not what we know that will hurt it's what we think we know or don't know that teaches us lessons. Regardless of what was done prior or is done now, If we don't know why the cap was 2.0 or why a 1.4 cap is the solution we don't really know if the expansion tank is the problem or the 1.4 cap the solution.

I have no idea what the average estimated failure rate is or about after how many miles it normally happens. I haven't read anything that was alarming and haven't had the problem so it would have been easy for me to ignore it. What is a good estimate?

[Ven]

I found this on realoem part X-reference for 17137639023, a 1.4 bar cap

RealOEM.com - Part Search

E53 (and e83 too in my case) fitment is applicable but no gasoline models. There may be no conspiracy but has this got anything to do with emissions and or regulations?