91 LX 70k miles, AC 2.2l

I recently had the water hoses and thermostat replaced in my '91 LX and after a few uses noticed that the temp was running hot, 3/4 on the scale. I did a bit of checking the gauge sensor seems OK - measured resistance hot and cold and measured resistance values were in spec. Removed themoswitch A and tested per manual and it closes at about the recommended temp. Shorting the thermosw A terminals and the fan comes on. Swapped the fan and the power window relays and windows operate OK, swapped back. Both fans operate with AC on. Timer fan comes on. Removed replacement thermo and tested it seems to begin to open about 10 to 15 degrees above the recommended and is fully open 10-15 above 194 F. Top hose is generally warmer than bottom although the longer I run the engine the closer in temp they seem to be.

I get plenty of hot air with heater on. AC is Ok.

I'm about to give up and bring it in with the fear that the head gasket is blown...

Just wanted to know if I should replace the thermo given it appears to be operating above the recommended values?

Also, if the temp gauge is at the 3/4 point should I expect the radiator fan to be on?

Many thanks.

greg

 

Yes and yes.

For more detail, yes the thermostat does not cost much and seems suspect. Be sure to bleed the air out.

Yes if the temp gauge is getting that high BOTH fans should cycle on when the ac is off.

 

Thanks for the quick reply poorman!

I suspect the thermo and will take your advice. I note the fans are NOT on when I have the 3/4 gauge condition so I'm a bit perplexed by that however will start with the thermo and go from there. Any advice on the best method for bleeding the air out?

Again many thanks.

greg

 

Advice on bleeding, not trying to start a debate, just going to say what has worked for me on my Accords.
Once you have the new t-stat in and sealed up, open the bleeder (12mm?), turn the heat to heat, begine to fill the rad slowly until you start to get coolant coming out of the bleeder, close the bleeder off, top off the rad. Replace cap and start the car, let it run for ~20 minutes or so, keeping an eye on the gauge and watching for the fans to cycle.

 

Poorman is rite on on how to bleed system do this then check coolent sw a near thermostat 2 wires 1 blu 1 blk with key on jump the 2 pins and fans should run if thay do it is a bad sender if not look elseware