Got a weird problem going on with my 2001 2.3L XLT.

This happened once about two months ago and I didn't think anything of it. Now it has happened multiple times and I am wondering what is going on.

I have an ultra gauge so I can see the engine temp. It normally goes up to about 220' F. Then will drop back down to about 200' like normal. However what seems to be happening for no reason or randomly is that I see the temp gauge on the cluster start to dip below the middle point and when I start looking at the ultra gauge it drops temp to about 170-180' F. I replaced the OEM thermostat with another OEM thermostat yesterday and it did it again today. This seems to happen more when I turn the AC on to MAX and after about 35-40 minutes I can see the engine temp drop. It doesn't drop below 170' F but I can't remember this ever really happening... This doesn't seem normal to me.


No other sighs or problems just random. I had to stop pretty quickly a few times and almost immediately after that I noticed the temp going down. If I stopped abruptly again the temp would start to go back to normal. I'm wondering if there is something along the lines of wiring but not 100% sure what to check. Some days I can drive and nothing happens and the temp stays normal the entire time. Other times the temp my dip below like the above but then after 20 minutes go back up to normal...


-Nigel

 

When AC is turned on the cooling fan locks in to move air across the AC coils - fan on also cools the engine. Thermostat is supposed to close to compensate. When it starts to dip shut the AC off and watch the temp gauge and see what it does.

Your cooling fan clutch could be getting stuck on as well so its cooling too much. Does it sound like a 747 taking off when you start it?

 

I replaced my fan clutch for a new one about 2-3 years ago. It does sound like a 747 in the very beginning for a few seconds then quiets down.

I'll have to run that test today. When I drove to work this morning with no AC the engine temp stayed where it should have at 220. I'm sure it will be close to 100' F temp outside today by 2pm so when I have the AC on I'll see what it does.

I do know I have turned off the AC immediately as I saw the engine temp going down but it didn't immediately return to the normal position or temp.

Is there a test for the cooling fan/clutch to test to see if it is in fact getting stuck on?

Thanks for the help.
-Nigel