Is this a thermostat issue?

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Dec 5, 2021 | 06:47 PM

#21

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Quote:

Originally Posted by lionelhutz

Geeze, high speed fans are commanded on at 235*F so the coolant reaching 230*F isn't indicating there is a problem.

Capt. Shark - you probably had the AC off since it was colder out. The low speed fans are turned on with the AC and if the coolant temperature climbs enough then the high speed fans are turned on. With the AC off, the fans are not running at all until the coolant temps climb enough to turn them on.

Quote:

Originally Posted by Capt. Shark

You may be on to something. The A/C was not on, I can't remember the last time I drove it without the A/C. That's the first thing I'm going to look at. Thanks.

Quote:

Originally Posted by Capt. Shark

I know this dropped off the first page but I want to say thanks for the help. Idling with no A/C temp goes to 230*, fan comes on and temp drops back down to 220*. With A/C on fan runs continuously and temp stays at 210* where I have always seen it before. Works as advertised.

This place rocks

Glad your issue is resolved.

I tested my 2004 today. The car was idling in the driveway with the AC running with an outside, late afternoon temperature of 75 degrees. Below are the temps:

4:55 PM - Start
5:00 PM - 218 Degrees
5:05 PM - 219 Degrees
5:10 PM - 220 Degrees (Vertical Top of Gauge) - 1st Fan Turns On
5:15 PM - 230 Degrees
5:20 PM - 235 Degrees
5:25 PM - 240 Degrees
5:30 PM - 240 Degrees
5:35 PM - 245 Degrees (2nd Fan Turns On
5:40 PM - 250 Degrees
5:50 PM - Near 260 Degrees Redline (After Engine Revs)

Similar to the last few longer drives, the timing seems similar whereas I rapidly get to 250 degrees only to turn off the AC and cool then engine once out of heavy traffic. I have a low temp stat installed so I'm trying to figure out the best order of diagnosis.