never gets up to temperature, always runs cold?

[k9]

My 325i always runs at 1/3 of the way up the temperature gauge unless in traffic, and it seems quite heavy on fuel I'd say 18-20mpg.
I've heard of some people talk about a blue temperature sensor, where is this and how do I know if it's not functioning and where can I get a new one?
Cheers
K

[Gwynleym10]

If is really is running cold then its the thermostate stuck open. Running cold will affect the MPG.

A broken blue sender is only when the ECU "thinks" it is running cold. If it really is running cold then there is probably nothing wrong with the sensor, if that makes sense?

[jmc330i]

My 325i always runs at 1/3 of the way up the temperature gauge unless in traffic

Thats how mine used to run. I dont think I ever saw the Temp guage go much over 1/3, unless I was in traffic on a hot day. And then, I never saw the needle go much above 1/2.

[k9]

forgot to mention I changed the thermostat and no difference.

My car runs cold on a run and actually overheats in traffic?

My fan is on all the time but never speeds up, even if the engine is hot?

Is that normal?

Cheers

K

[Gwynleym10]

Ah

Its the fan clutch then.

When its warmed up stick a roll of paper in the fan, if it stops i'm right. If it doesn't and shreds the paper I'm wrong (never!)....

Yes it looks like it spins, but its spinning slower than it should, epescially in traffic.

You may also have a temperature sending sensor problem as well then.

[astondg]

Well my 323i usually runs anywhere between just above the blue bit to about 1/3. On the race track it sits on 1/2. I get about 12mpg. Doesn't overheat though, and my fan clutch is new.

Aston

[JazzMan]

My old 325i used to run bang on halfway when I got it. After an oil change it sat at 1/3 (it didnt have masses too much oil that was really old/glupy when I first got it). Engine still seemed up to temprature under the bonnet.