MR2 runs cold

speedman007

just a question about my 87 mr2. the temp. gauge stays at about the 1/3 point while it should be at the 1/2 point. the car runs fine but the car will not shift into overdrive until the gauge reaches the 1/2 point. i have to drive the car about 30 miles on a warm day to get the gauge to the 1/2 point. do i need a new thermostat? or is this something else. any thoughts on the subject would be very helpful. thanks.

lngtonge18

I would say the thermostat is stuck open and not allowing the engine to warm up completely. Replace it and see if that fixes the problem. It only costs like $8 and should be easy ti replace.

Mr_Shiftright

Yeah, good guess...it's definitely not good for your engine to run cold. The hotter the better (within reason, of course). I don't know how the overdrive is affected, unless it is somehow controlled by a temperature sensor.

spokane

Honda automatic transmissions do utilize the coolant temp input -- they won't upshift to 4th gear until the temperature is near normal. I believe the required temp is about 78C (172F). Perhaps the MR2 is also programmed this way.

In any case, I agree that replacement of the thermostat should be the first step.