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Old 10-15-2012, 07:57 PM
robertobaggio20 robertobaggio20 is offline
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Join Date: Oct 2009
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Originally Posted by BMR_LVR View Post
I think you can feel comfortable proceeding since the mechanic indicates that a blown HG is unlikely. A compression test should also confirm this, but he would probably charge you a lot for that. I am not one to typically recommend buying a lot of parts prior to failure, however, the cooling system is so critical to this engine's life. I do recommend a full coolant system overhaul when you are having problems like this. I did mine for ~$600 in parts via the internet. I did it in an afternoon taking my time. It's really not that hard.

I'm glad the news was good relative to the HG.

Good luck.
Did you read the bimmerboard thread posted by my525iT ? It guided you on deliberate methods to check on your water pump and thermostat.

As I expected, this was a thermostat or water pump issue. I was quite sure that you were wrong when you said that most of the online posts that you've read suggest that these problems are more serious.

However, if there is no coolant circulation, your engine should be overheating even at idle. Perhaps there is coolant circulation, but it is very poor.

However, I do not like the extra vapour in your tailpipe. This is not normal for an E34, expecially if another vehicle does not exhibit the same amount of vapour (which eliminates environmental issues). If i were you, I would purchase a compression tester for $30 on ebay and do the compression test myself (its easy, check youtube) to be absolutely sure that nothing is up. Also, ask the mechanic to explain the extra vapour, see what he says.

Finally, my suggestion is that you get a composite impeller water pump, instead of a cast iron or stainless steel one. Composite pumps do not corrode, are tougher than plastic, as strong as steel, and almost as light as plastic. Thus, the load on your wp's bearings is reduced, greatly extending its service life and reducing its likelihood for sudden failure. O reilly sells one for $50 before shipping, with a lifetime warranty. Turner sells a BMW pump for around twice that price, but with no lifetime warranty.

Furthermore, I suggest that you pick up a new water pump pulley that's made of thermoplastic these days. It is much lighter than the existing metal wp pulley and your car will be faster. I just did this and am very pleased with the results. Since the pulley needs to be removed to access the fan clutch, you're not going to pay extra for labour. The pulley should cost under $50 and is worth paying for. Please confirm the material of the pulley with customer service if you're buying it online.

I would not bother to replace the fan clutch. If your car did not overheat with a busted water pump and a possibly busted fan clutch, then I think your system would be flawless with a good pump and existing clutch. In fact, I would recommend that you remove the fan clutch, fan and fan shroud entirely. I've been doing that for 2 weeks with no problems. Confirm using Bentley's test procedures first that your auxiliary cooling fan is working well at both low and high speeds, before you delete the fan clutch.

Unless you have already done so, I would suggest that you change the bleed screw and rad cap to new ones. They should only run you $15 in total.

Please purchase the compression test kit and conduct that test on your car.
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