M52 running a bit hot

[Jimbob]

Hi guys,

When driving my car in the evening, no traffic etc, the temp needle sits ever so slightly over half way. However when I get stuck in traffic or it's a very warm day the temp needle starts to waver near 3/4's and slightly above.

I haven't got my part numbers to hand at the moment but I think I'm using the 81c/88c thermostat switch and the E36 aircon fan with Dan's loom. It takes a while for the temp to drop back to halfway once the fan has kicked in so I'm not sure if my fan is just shit or I need to change the thermostat switch to a lower threshold? Or is there a way of modifying the front of the car slightly to increase airflow?

Any help is appreciated!

[Jhonno]

New thermostat?

Hows the rad? What rad?

[Jimbob]

Yeh new thermostat was fitted, however the rad was used from the E36 328i, looked in good nic at the time of fitting.

[Jhonno]

Pics? Rads are long term service items..

Could be a faulty thermostat..

[DanThe]

If you have the 80/88 fan switch the fan would be running as soon as the needle got to half way, sounds like you have the 91/99 switch to me.

[Jimbob]

The part number I have here is 61318361787, according to realoem that's 80/88 but looks like there's a newer version (61318376440).

Anyone able to confirm the correct part number please?

[Jimbob]

Strange things happening with this, I had to use the BMW for work on Tuesday and whilst it didn't run too hot I remember checking to see if the fan was on, which it was. However the other night the temp needle nearly crept into the red, before switching it off I quickly jumped out to see if the fan was on - it wasn't!

I've now run a manual override switch, but in the mean time I need to figure out why it won't come on automatically, could it be a faulty temp switch on the rad?

[DanThe]

It is 61 31 8 361 787
Has the switch temps stamped into the side of the brass

Low coolant level or bad connection possibly? Unplug the switch and bridge the terminals to check the fan/wiring

[Ianb]

I had exactly this issue, and am running correct temp switch etc - Turned out to be air in the system. My guess is that the air lock landed up near the fan sender. On a 2.8 i'd be scared of thered section of the guage ( mines an M50 ). To bleed it i landed up jacking it up at a ridiculous angle and running till hot, then filling header to top, running at 2k rpm then open bleed screw a bit. It took me a couple of hours but temp much better now.

[Jimbob]

Thanks for the response guys, Will it is running with a relay. Based on Dan and Ian's posts sounds like air lock / low coolant level......feck sake was hoping to dodge bleeding the system again

[shedrool83]

I have the same problem .I used the donor cars rad and reckon its that thats the problem ie choked.
Going to get a new one when funds allow.