need help on my 90 525I [Archive] - Bimmerfest - BMW Forums

: need help on my 90 525I

11-24-2008, 11:16 PM
My car started to overheat on me about a mile from my house and then it died a couple houses away from mine. Now when I start it, it runs ruff and when put in gear it just dies. It will idle ok but it is ruff and when you push the throttle it hesitates before it picks up on RPMs. Any ideas what it could be?

bimmer dot info
11-25-2008, 06:35 AM
How long did you drive it while it was overheating? How high did the needle get?
Is the check engine light on?

11-25-2008, 10:50 PM
the engine light never came on, but it was only about a mile with the needle up, but it kept coming down and going back up

bimmer dot info
11-26-2008, 07:27 AM
How high did the needle get?
Does it overheat at all speeds or is it when you are stoped? When was the last time you replaced the thermostat?

11-27-2008, 10:43 AM
The needle was all the up, it would drop alittle at higher speeds but not much

11-28-2008, 11:35 AM
I'm not sure if this will help you or not but about a year ago, I had an overheating problem with my 90 525i, replaced everything easy to no avail, I took it to a friend of mines garage and had him take a look after a long diagnostic period it turned out that the impeller came off of the back of the water pump so there was no flow at all. Long story short it got cooked pretty good and also overpreassurized the cooling system that blew all the seals in the radiator and the headgasket. I hope you don't have the same problem I did but none the less something to think about.

bimmer dot info
12-01-2008, 08:39 AM
Since you let it get that hot and you are now having problems with it you have probably damaged the head gasket (possibly the head). Test for compression and look for oil in the coolant or coolant in the oil. Check for leaks into the cyl too.

12-12-2008, 07:01 PM
There are no leaks anywhere so I'm clueless

12-14-2008, 07:12 PM
Is there an easy way to check the compression

bimmer dot info
12-15-2008, 06:46 AM
Compression tester.
You screw it into the plug holes and (after you disable the fuel pump and clear the fuel in the lines) use the starter to turn the engine over about 3 or 4 times a cyl. Make sure you ground the spark.
You are looking for low pressure or large variations in pressure between the cyls.

12-15-2008, 09:46 PM
It will start up at first and run real nice, but after a few minutes it will start to hesitate and starts to run ruff. I have not been able to check the compression yet.