I have 92 Accord that had a coolant leak. The leak turned out to be from a crack in the thermostat housing. I changed the housing and replaced the thermostat. When I test drove the car it started to overheat. I noticed the fans weren’t running so I removed the terminal from the housing and used the jumper to test the fans, which turned out to work. So I replaced the thermal fan switch, took the car for another drive and the car still overheated and the fans still weren’t coming on. I used the jumper to get the fans to run and drove the car with the fans running 100% of the time and it still overheated. The temp readings from the guage are very erratic, hot then cool then hot again. When I shut off the car I can hear the coolant boiling. This car never ran hot until I repaired the coolant leak. Could the new thermostat be bad? This is an old car and don’t want to put a bunch of money into it. Any suggestions?

Thanks.

 

You have air trapped in the cooling system. Open the air bleeder on the thermostat housing and pour coolant slowly till coolant comes out of that bleeder. Car must be cool to do this.

good luck

 

I did that also

 

Either you did not get all the air out, or you may have a bad head gasket. Rapid changes in coolant temp can be a signal of bad head gasket. Smell coolant for gassy smell. Any evidence of oil in coolant or coolant in oil? Any engine missing on startup (water on plugs from bad head gasket)?

I would allow car to cool and carefully refill and bleed the air to be sure.

Car will run cool w/ only a little forward speed (20-30 mph) and no cooling fans, so cooling fans are not the problem.

Are you sure you installed the thermstat correctly w/ air bleeder to the top?

Did car overheat badly when the thermostat housing was cracked? If yes, then a bad head gasket may be the problem.

good luck

 

I've checked for symptoms of a blown head gasket and everything seems fine. The car never overheated whenI had the coolant leak because I alwayschecked the coolant before I drove it. Strange thing is there was never any overheating problems at all till I repaired the coolant leaks and changed the thermostat. Could it be the NAPA thermostat I installed? Thanks for the info.

 

A bad thermostat is a possibilty, even though new. I've had this happen w/ aftermarket thermostats, and only purchase OEM honda thermostats. They work very well. I would go OEM and replace the thermostat.

good luck

 

Would that cause the fans not to work properly?

 

Cooling fans are not likely to beyour problem. The thermostat has no effect on the cooling fans.

Thermoswitch A controls the cooling fans coming on. When coolant temp reaches 195F the fans will engage. Fans will engage any time AC compressor engages, no matter what the coolant temp. Thermoswitch A is on the thermostat housing.

good luck

 

i like to put a tiny hole on the top of the thermostate to let air out,it works very well,my lincoln had a small gasket leak and it worked for 4 years

 

One thing I forgot to mention. When i drive the car and it get hot, the upper hose is very hot but the lower hose in only luke warm at best.