Coolent temperature warning, need help

[unhygenix]

Hi,
I own a 95 525i.
When driving today I noticed that my AC is not running as well. Then some 3 miles later I get a coolent temp warning (it was into the red zone), and smell smoke. I stop the car, switch off the AC wait a while and then drove without the AC.

The temperature did come down to almost middle, but I donot know what to do about this problem.

Please help me out, I am totally new to this. Whats the problem and how can I correct it.

Thanks,
Praveen

[Adnan]

Hi,

Your fan clutch could be failing and as a result, it isn't able to keep up with the heat load. Or, your temp sensor for the auxiliary fan may be defective, and so the aux fan isn't coming on when it should. Lastly, it could be the aux fan itself.

Start with the clutch, read Bentley's procedure on it to see if it's bad. Odds are, that's the problem if it has never been replaced.

This assumes that you have an otherwise okay cooling system, that is, fluid levels at normal, no air in the system, etc.

Regards,
Adnan

[califblue]

most likely fan clutch., if you can turn it free with the engine off it istoasted..just happend to me...$100 and easy 10 min job...use the search for fan clutch

[BigD]

A fan clutch is hard to diagnose, unfortunately. A dying fan clutch will still have resistance, and if you unbolt it, your car will overheat a lot faster. But it's not good enough for when the car gets very hot very fast in stop n go. The one sort of good way to test it is when the car starts getting hot, the engine should sound like a vacuum cleaner when you rev it, from the fan clutch locking up and the fan going full blast. But if it's old, just replace it.

[ScottyWM]

Make sure you first check the fuses for your auxilliary fan. Could be that simple... If it only overheats with the AC on, I'd suspect something with the aux. fan (fuse, resisitor), not the fan clutch.

[Adnan]

...a bad fan clutch manifested itself as overheating on a very hot day with the A/C on. Aux fan, etc. were fine.

New fan clutch, problem solved. Although, I didn't see a sudden temperature spike, just a steady but rapid increase in the temp gauge.

Regards,
Adnan

[unhygenix]

Hi all,
Thanks again, I bought the bently last night, planning to diagnose it and post the results soon.

Hoping its not a big deal, the AC was not very effective, as in it usually took a lot longer to get it cool and I was not getting a lot of air out either.

Thanks,
Praveen

[ScottyWM]

Check and change your microfilter if you have poor airflow. You might be surprised what a new one will do. Make sure the AC is charged up, and you should be chillin'.

[632 Regal]

Check and change your microfilter if you have poor airflow. You might be surprised what a new one will do. Make sure the AC is charged up, and you should be chillin'.