Hello Experts,

My engine temperature will very slowly climb when I'm idling at an intersection or when driving uphill. Once I accelerate from an intersection or begin driving on a level or declination the temperate quickly returns to an acceptable level. I have noticed that neither cooling fan will run during engine operation, UNLESS the AC is turn on. At which point both the engine cooling fan and the condenser fan engage. Once the engine is turned off the engine cooling fan will intermittently turn on for ~10 minutes.

I flushed my coolant system and and replaced the coolant several months ago. I have verified correct operation of both fan relays and fuses.

My thoughts are the fan switch? But I don't know how many circuits/sensors control this fan. And since my access to a hoist to drain my coolant is about 45 minutes from a parts dealer I would like to fairly accurately determine my problem before draining.

Thank you in advance,

Mrader.

 

ok, check these things.

1st- check the thermostat, replace it and see if that fixes your problem. It might be getting stuck.

2nd- and its a doozie, I had this happen to me, the end result was a waterpump that snapped in half.

3rd- on the thermostat housing there is a sensor that monitors the temp of the coolant. Test that sensor to see if it working correctly.

In my opinion when this happen to me #2 was the culprit. good luck

 

I believe on 3rd gen B20s the coolant temp sensor is located on the bottom of the radiator? Correct me if I'm wrong. I've done 3 radiators in three different 3rd gens. I may be getting it confused with work as all I see are Toyotas everyday.

 

the location of the fan switch is on the radiator for both 3rd gen preludes and accords