E30 M20 Overcooling in 90F weather

[flyerman1202]

Hey everyone!
My E30 has been overcooling, it has been consistently over 90+ Degrees here, and my temperature gauge won't move past the 1/3 mark unless I'm idling, when I'm sitting at idle, it will mosy right over to center
I replaced the thermostat, I even replaced the 75 degrees with an 80... and tested the old one, works fine.
Where should I start, should I replace the temp sensors? Check the SI board? Is my whole engine dying? Any help would be appreciated,
Thanks!!!

[roguetoaster]

Start by checking the actual temperature on the inlet and outlet hoses at the radiator when the car is fully warmed up. An IR thermometer should get you close enough for diagnosis. You should see around 180F at the hot hose and 20F or more lower at the cooler side.

Most likely you just have a gauge issue.

[nando]

What is the problem? Sounds like a perfectly working M20 to me. They don't run that hot. FYI - 90c is about right in the center of the gage. So it sounds like everything is fine, in fact, possibly your clutch fan isn't working if the temp is creeping up at idle.

[ovo_e30]

Looks normal to me. My e30 does the same thing. The 1/3 mark is around 170F according to my standalone ECU and the center mark is around 196-200F. Idling or driving in the city I’ll sit at the center mark and driving on the highway or long stretches of road I’ll be around 1/3. Your e30 is fine

[ADEN]

Make sure you installed the thermostat rubber ring gasket sometimes coolant pass through it when revving.

[TobyB]

I've been playing with too many engines- wasn't the stock thermostat 88c?

t

[flyerman1202]

Yeah, I have the gaskets in, A friend of mine also suggested that the fan clutch could be going out. though he's not into these things, so taken with a grain of salt
I'll try to get an IR thermometer to check the temp of the engine, for peace of mind at least.
Last week it hit 112F outside. and it was still sitting at 1/3, while also having an 80C thermostat. That makes me think that it might be something more. Hell, maybe I'm just being a worrywart.
I'm hoping that I won't have to buy a new fan clutch, they can be not cheap. (but hey, that's an excuse to do the timing belt/ water pump too)

[digger]

It’s not your fan clutch. Your thermostat is too cold if you want the temps to be higher when on the highway.
80c is around the 1/3 mark as intended so nothing sounds wrong to me.