1990 525i, 236k, running very hot despite recent water pump replacement

[Unregistered]

I had my water pump replaced about 3 months ago - 600 miles, maybe, it's not driven much.

I was driving the other day and it red lined the temp guage. It did it at a stop light but continued as I drove. There were no noises.

The dealer said to tow it back and if it was warenty work, they'll pay the tow charge. I'd rather not have to pay the tow charge and take achance on them saying it's something else, another $600.

Any ideas?

You guys have been a great help in the past - Many thanks!

[rickm]

Here's a good link to peruse:

http://www.bmwe34.net/e34main/trouble/overheating.htm

Also, check the hoses. Are they hard or soft to the touch when the vehicle is running?

[Warren N.CA]

fry the head gasket and that WOULD be an expensive repair, indeed.

I had my water pump replaced about 3 months ago - 600 miles, maybe, it's not driven much.

I was driving the other day and it red lined the temp guage. It did it at a stop light but continued as I drove. There were no noises.

The dealer said to tow it back and if it was warenty work, they'll pay the tow charge. I'd rather not have to pay the tow charge and take achance on them saying it's something else, another $600.

Any ideas?

You guys have been a great help in the past - Many thanks!

[AllanS]

I had that happen in my 525i- turned out to be the thermostat, stuck closed. Don't drive it when it gets near the 3/4 mark- pull over and sit it out. I had this happen on the highway, with no cellphone, and pulled over every couple minutes. Driving on an overheating engine will cause headgasket failure, which is expensive to replace (well, more expensive than a 20$ thermostat, anyway).

[cerdman]

Take a look at the throttle body. On my 90, it was leaking and not only losing coolant, but allowing air in the system. Its an easy fix, even for a novice like me and then "burp" the cooling system. I have not checked, but I think Bruno's site is where I got that info originally. www.bwm34.net.
As the others have said, it is very important not to drive the car at more than 3/4 on the gauage (I prefer 1/2).

[stevebuk]

If it isn't still doing it it may have been caused by an airlock in the system, they can be a real pig to bleed.

I've just had a head gasket replacement on my 525i as the thermostat stuck closed and took the head gasket out.

You need to keep a close eye on the temperature dial and don't drive if it gets to 3/4. It's quite a sad feeling when the OBC flashes No oil pressure!