E36 BMW 318i Temp Gauge Staying In The Blue

[Sammo]

Morning Everyone,

When I was coming home from work on Monday I suddenly clocked that my temp gauge had shot into the red! I quickly turned the heaters on full blast and the temp gauge gradually dropped back down to half way. Now normally the temp gauge will sit slap bang in the middle and hasn't deviated from this since I bought the car, however in the last couple of weeks the temp gauge has occasionally not been working at all and then suddenly bursting into life. When I got to work yesterday I got one of the techs to replace the rad fan switch and coolant temp sensor to try and sort the gauge issue out and hopefully stop the car from getting too hot again. When driving home from work last night I then noticed that the temp gauge was only getting about halfway into the blue, and even this took a while! If I turned the heaters on then the needle dropped further down the blue, so the gauge is reading something.

I thought maybe the thermostat was sticking open, but the fact that the heaters get nice and warm kind of rules that out!

Can anyone suggest anything as I'm not sure where to look next.

Cheers

Sammo

[andyf]

The heater could still work to a degree if you had a dodgy thermostat, the water would still probably be warm enough. I would look at the thermostat personally, I usually find that`s the problem. I have no idea how cheap they are on yours but assuming they are a sensible price I would change it for peace of mind.

[Sammo]

We changed the thermostat about half an hour ago and still no luck. It's actually looking like the waterpump might not be flowing properly! Annoying as I only replaced it a couple of months ago!

[kevralpina]

If you have got the later 1895cc engine more than likely head gasket as they are prone to it try to get it checked out hope this helps

[ChasR]

What brand of sensors did you buy?

[bmw2101]

i have ablown a few m44/m42s up, i take it yours is a m43? 8v.


There should be 2 sensors on the block for temp, i think one does the gauge etc, and the other is for the ecu.

Have you had water out of the system? I mean is it now airlocked? undo the little black screw on top of the rad and let it warm up and see if it needs water.

[Sammo]

It turns out the replacement sensor was faulty. Changed that over, along with the 2 plastic housings that shattered when it overheated and all is well again!