Hi
I have a funny feeling that my thermostat is stuck open and was wondering if there is any simple test to determine if it is open?
I just drove home about 35 miles doing 70 mph on the freeway. The gauge never got above 60C, the weather here is 52F = 11C
I would expect the gauge to go up to at least 80 or 90C
Does the 197 300E run this cold or is the thermostat stuck open and the car never heats up?
Thanks
Sure, but you have to take it out. It will take you ten minutes to replace the thing... just replace it and see if the problem is fixed.
--scott
Sure.
On lots of vehicles you can open the rad cap on a cold off engine, then start it up and look inside. If you have fluid flow right away, your thermostat has failed.
I have seen an epidemic of failed open thermostats in the last couple years, mine and our tenants' included. More than I have seen in the last 40 years.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 'New' frame in the works for '08. Some Canadian Bush Trip and Build Photos:
Idle the engine from cold start. Feel the front center of the radiator with your hand. Stay away from the fan side, because electric fans will start whenever they feel like it. If the center of the radiator warms up early, well before the gauge reaches the set point (85-95 C), then your thermostat is stuck open.
I also like Mike's suggestion to look for flow in the top of the radiator. IMO sometimes that's not enough because of radiator geometry or thermostat stuck partially open. So do both; more info is generally better when working on cars.
Oh yeah, you might have a bad temp gauge, but the chance of a bad thermostat is a lot greater.
IIRC all modern car thermostats are at least 180F = 82C, so from your gauge symptom alone, it is most likely the thermostat. Does the heater seem weak too, never doing a good job warming up the passenger compartment? That is more evidence for a bad thermostat. If you know you have a weak heater too, then more testing is probably not even necessary.
--Dave
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