Hi everyone, hope someone can shed some light on my heating problem.

I have a 1989 318i with 51k on the clock, an old boys car before i bought it 6months ago.

I have always noticed the temperature gauge has always sat at 12oclock, but now when stationary really starts t rise quickly, the fan cuts in just before it hits red, and reduces it to the 12 position. Why has this suddenly started to happen? I thought it might be the end of the coolants life, and so replaced last week, tis has not aided the situation. Is it the thermo thingy that makes the fan cut in?

 Please anyone had this happen to them, and hw can it be solved.

 Cheers O

I'm not sure of the set-up on the 318i, but the M3 (E30), has a two speed fan.  One speed keeps it around the '12 o'clock' mark, the other cuts in around the red.  Ordinarily you would never need the second speed, but it seems to me that, either your thermostat is playing up or the sensor has gone wrong.  The fact that the fan cools to 12, makes me think that there is something wrong with the connection from the Thermostat to the Fan, loose wire maybe??

Hope this helps,

James

How come the water pump?

The pump often uses a plastic impeller which either wears and reduces its efficiency or seperates from the drive spindle. With an E30, pure age steps into the equation.

They are such a common failure on the E30/36/46 that I would recommend changing them as soon as any problem materialises with cooling.

Have a look at my site for guidance on doing it on the M42 engine which is very similar in this regard to yours.

http://www.esatclear.ie/~purcellb/

Im going to try thr themostat, the test on the fan with the paper, and then may be replace the pump if need be

Owen

I have spoken to GSF and BMW and they say its the coupling on the fan, the pump would have just given up, and the thermostate would be showing more serious signs. Apparantly its really common, hence why its the most expensive bit to replace.

But you described the fan as cutting in - does that mean its electric? That's what I had assumed from your initial post.

GSF, etc. will be referring to a thermo-viscous fan, which does often fail. If fitted, you can check it by running the engine and then try to stop the fan blades with a rolled up newspaper - keep yours hands clear! If it easy to stop then it is trash. It is very easy to replace.