thermo gauge up then down...
 

I'm back for more knowledge!

My 90 accord is runnin great thanks to all of your help guys... I'm fine tuining her now... my issue at hand is this...

When sitting still, or at a light.. the temp gauge will be in the middle and blow hot hot heat.. but sometime when I'm rolling down the highway, or above 55mph, the gauge will drop to below the c, like its cold.. then the heat won't blow as hot... but still warm.

I replaced all 3 sensors under distributor and the sensor by the upper radiator hose already, with clean good looking scrap yard sensors... car runs and drives great, does not over heat even when sitting, and fans turn on, well I know one does...

Point me in the right direction fellas.. thanks!

Sounds like a stuck open thermostat or possibly a missing thermostat. Get an OEM thermostat from the dealership. Don't get an aftermarket part on this one.

Did the shop that replaced the timing belt also replace the water pump and coolant?

If coolant is new, drain coolant from the radiator into clean container and reuse. If coolant is old, then replace coolant when replacing the thermostat.

Search around about bleeding air from cooling system when refilling.

I think it may be a stuck open thermo... ill replace that today, and ill know later..

As for radiator fluid, its Cleen and green, topped off, no leaks. Unsure if they did water pump...

She does great after an hour of driving.. thermostat gauge will work fine... its just say 10 mins after I start up, and jump on highway.. if I sit for a few let it stay running, then thermo gauge is fine the rest of the trip, so the stuck open thermo is a good thought..

An OEM thermostat is best. They warm fast and are reliable.

good luck

Sounds good... ill grab it on mondayyy! thanks fellas

This has performance characteristic of a cheap thermostat. It first slowly warms (partially open at cold) then when it finally opens, it overshoots (too open) and engine goes cool again. Finally after some time it manages to reach set point. New theremostat should put you right.

good luck