Temp gauge being a silly bugger

[bexwoods]

Hey guys, I’m properly stumped on this one so thought I’d reach out to see if anyone has any bright ideas.

We’ve got my beautiful Errol running again for the first time in 2.5 years, but the temp gauge seems to be reading hot.
It goes well past ‘temp’ and suggests it’s boiling after a short drive, but the actual temperature of the block, rocker front and back and expansion tank all read the same as my brothers 325i that’s gauge reads normal.
So, in short, the car is not running hot, we’ve changed the dials and it does the same thing so it’s not the gauge itself (been fully refurbed so I’m glad about that one!), we’ve tried a new temp sensor and checked the earth etc all ok.

Anyone got any bright ideas?


Anyone know if it’s linked to the blower motor in anyway? This seems to be on its last legs so have ordered a new one.

Thanks in advance 🫶

[martauto]

Have you checked out the brass nut behind the cluster , it plays hell with stuff like this if not tight.

Mart.

[bexwoods]

Have you checked out the brass nut behind the cluster , it plays hell with stuff like this if not tight.

Mart.

The earth one? Small one maybe 6 or 8mm?
Yeah checked that and it’s tight.
Had the whole unit refurbished by a specialist so it shouldn’t be the cluster really

[BenHar]

Have you got the connecters the right way round on the blue and brown sensors?

Ben

[fixedwheelnut]

check the resistance of the actual sensor at various temperatures against the following charts, also check the same resistances at the ECU pinouts, the variation should be minimal, if there is a great difference you will be looking at a wiring fault usually at one of the connecters.

White temp sensor for guage

White temp sensor for guage

Blue temp sensor for ECU

Blue temperature sensor for ECU

Most common is the round one under the inlet manifold.

https://www.e30zone.net/e30wiki/index.p ... Temp_Gauge

[bexwoods]

Thanks guys, that’s useful.
I’ve also seen changing the earth cable (12511714039) work for someone on YouTube so I’m guna try that too!
A few bits to try now when he’s back from paint (sorting the bonnet!)

[DanThe]

Great job! Undercarriage looks fantastic

[bexwoods]

Great job! Undercarriage looks fantastic

thanks Dan! Looks as good top side now after an almost full respray!!

[bexwoods]

SORTED IT!!!

Appears the earth cable had had a short circuit, possibly caused by the rusted blower motor.
Changed both and gauge acting perfectly!

[bexwoods]

Holding steady after 30 minutes of running

[martauto]

Nice to see, it had to something like that.

Mart.