Overheating - BMW Forum

jonnyblaze · 03-27-2005, 06:49 PM

hello all,

i have just recentely discovered that my 91 525i overheats while idling. ithappens really quickly. when the car is warmed up and sits for a few minutes the temp guage goes way up and the coolant temp messsage comes up on the dash. but as soon as i start driving it immediately drops down to the normal runing temp. i checked the fluid level and it was fine so i checked to see if the fan is running and it is so im not sure where to go from there. any suggestions?

thanks in advance,
jonnyb

billB · 03-27-2005, 10:19 PM

My guess is either the plastic impeller in water pump, thermostat or fan clutch...start with the least expensive and work your way up....also do u hear the auxiliary engaging/front of radiator?

325isBaby · 03-29-2005, 08:02 PM

Easy way to check...see if you have heat coming into the cabin (like max heat is it hot or cold?) if it's cold then there is no flow, so you've narrowed it down to the waterpump or t-stat.

tacroteau · 03-30-2005, 11:10 AM

I have the same problem, I also have poor heat at idle. I am replacing the water pump this week. Its only $50.00 and if thats not the problem I am having the cooling system pressurized and flushed (around $100.00). But our problem is definatly a coolent FLOW issue. As long as your interior heat sucks at idle, you know its not your fan clutch. Let me know how it goes.
Tom

Bear · 04-02-2005, 07:12 PM

I put my money on the fan clutch. I had same symptom with my E32 and changing fan clutch solved my problem. My belief is if she overheats at idle or low speed and is fine at high speed it is the fan clutch.

325isBaby · 04-04-2005, 09:50 PM

If you believe that there is a good chance you could totally misdiagnose the vehicle...you have to take into account all the variables...how to determine if it's a coolant flow problem or a lack of air movement. be careful or it may cost more $ than you originally planned on spending! Just a caution

nukeduster · 04-06-2005, 12:45 PM

Quote:

Originally posted by 325isBaby@Apr 4 2005, 05:50 PM
If you believe that there is a good chance you could totally misdiagnose the vehicle...you have to take into account all the variables...how to determine if it's a coolant flow problem or a lack of air movement. be careful or it may cost more $ than you originally planned on spending! Just a caution

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I've also seen it be bugs stuck inside the radiator plugging up the fins on high mileage vehicles alot of times.