my 2005 mustang gt is starting to suddenly display engine overheating. It has done this off and on but not constantly. Any suggestions.

 

Is there any pattern to the conditions under which it tries to overheat? (Like only when stopped in traffic, etc.?)

Has any part of the cooling system been serviced recently? (Fluid change, etc.?)

How "suddenly" does the dash report overheating? Is it just a swift motion from C to H, or does the needle erratically jump?

 

It's very sudden it goes instantly from c to h. I did a systems check and said everything is ok. It happened a few weeks ago then again yesterday

 

I also want to add I pulled over immediately when I felt the hood it was still cold

 

Those are the typical symptoms of a thermostat that's stuck closed. Replace it ASAP before you end up with a blown head gasket.

 

Feeling the hood is not a good indicator. Doing the basics will help to pinpoint the problem. You can use a Infrared thermometer to get a reading at the thermostat housing. Make sure your fans are running properly and fluid level is correct.

 

I'm afraid I don't know much about how thorough the "systems check" is, but your description sounds like a fault in the gauge, the temp sending unit, or somewhere in between.

I like dusman59's suggestion. Run those basic checks and see if it really is overheating.

 

It's the fan controller module. Mine started doing that too. I Just replaced the whole fan assembly with the GT500 one and got a 3 row aluminum radiator while I was at it, but the stock GT fan is pretty cheap, no point in replacing just the module.
https://lmr.com/item/LRS-8607L/2005-...g-Fan-Assembly

 

A non-working fan would cause a gradual rise in the coolant temp. gauge from C to H, not a sudden one. I still think it's a sticking thermostat 'cause I had exactly the same thing happen a few years ago on my old '95 GT. Exactly 3 minutes after a cold start, the gauge would rocket from just above C to H almost instantly.

 

That is just an OEM type replacement for the stock one though? Unless you linked to the wrong item?


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