overheating / temp guage not reading at all

[enzo90]

so when i drove my car it will constantly overheat

i replaced the thermostat today thinking that was the problem and now the temperature gauge will never rise above the blue section

i checked all the wires and its all hooked up right

is there anything im missing?

 

[Doughnut]

So after changing your thermostat, does it still overheat?
It is possible the electrical connector (single pin for the temp gauge) is dirty, try giving the top of your dash (above the gauges) a firm hit incase its stuck.

 

[E30m42cab]

...try giving the top of your dash (above the gauges) a firm hit incase its stuck.

YES!

Seriously, works for me! Actually, it's not uncommon for the temp gauges in the E30's to go off into their own little world. Never had a problem with the Motometer unit, but the VDO unit gave me trouble with my temp gauge back in the day. Firm thump and it smartens up.

 

[enzo90]

it might still overheat after i changed the thermostat but i didn't feel too good about driving it without a temp guage

and ill have to give hitting the dash a try

 

[enzo90]

so i hit the dash and the gauge didn't move

i also measured the resistance through the sensor and it was dropping pretty rapidly

it went from like 400ohms to 300 ohms in 30 seconds

is that right?

 

[E30m42cab]

Try changing your temp sensor before you get too worried. Does your upper rad hose heat up? Does your car blow hot air inside? When you've had the car running for a while, does your overflow reservoir cap hiss when you undo it? I highly doubt your car is running that cold.
If you thing it's running hot, make sure your waterpump is turning and not slipping on the belt, and maybe take the thermostat out all together. Check your fan clutch to see if it has any resistance. Your rad might be clogged, or your water pump might have broken it's fins.
If you change the sensor, and it's still screwing around, try picking up a gauge cluster from a wrecker, and swap out the whole cluster or just the gauge itself ( it's easier than you think).

 

[enzo90]

the water pump was just changed like 40 miles ago and the top tube heats up. the car blows hot air and the radiator cap hisses when i take it off. the water pump is turning because its bolted to the fan and that spins just fine. i had the radiator out and ran water through it and it came right out the bottom so i don't believe that its clogged.

ill try changing the sensor today