Rattle from engine bay (Not Vanos rattle)

[rusteee 52]

I have a 97 E36 320i, I started it up when cold and there is a hell of a rattle in the engine bay somewhere, but only seems to be when the heater is on? It sounds like the air-con, as it clicks on and off (and sounds like its in the vicinity of the alternator belt etc), but in saying that I never had the air-con on. Does the air-con compressor still run when you have the heater on? It also seems to get quieter as the car warmed up but still rattles.

Also, I hit a goddam possum, and I wasn't exactly going slow. Suprsingly the damage wasn't too bad but it smashed the fog light out of the passengers side of the front bumper, and also I noticed there is something hanging down, looks like a rod (temperature sensor) of some sort, with 2 wires plugged into it. I don't wanna fiddle or try to find where it came from unless I know what it is, any ideas??

Cheers guys

Edited June 30, 2010 by rusteee

[elmarco 56]

Sounds like the sensor might be the external temperature sensor. I think they normally sit behind the passenger side fog lamp or headlamp. Someone else will be able to confirm.

As for the noise, it could quite well be the A/C compressor. While the compressor may not be engaged the pulley at the front still spins when the engine is running - it is belt driven. Best get it checked - if it sounds that bad it could seize and bust the drive belt.

[rusteee 52]

Sounds like the sensor might be the external temperature sensor. I think they normally sit behind the passenger side fog lamp or headlamp. Someone else will be able to confirm.

As for the noise, it could quite well be the A/C compressor. While the compressor may not be engaged the pulley at the front still spins when the engine is running - it is belt driven. Best get it checked - if it sounds that bad it could seize and bust the drive belt.

Oh thats good, I was hoping it was something like that.

Yea I want to take it in and get it checked before it does gets worse, but seen as I live in the middle of nowhere, its hard to get the car to a specialist on a weekday lol. It does sound like the belt, or aircon, it's something that cuts in and out all the time anyways.

Cheers for the help!! Much appreciated

[JFry 1]

The temp sensor usually plugs into the side of the brake duct. I've left mine wrapped around some other wires, my brake duct doesn't exist anymore