Overheating all of a sudden but runs fine?

2003 CHEVROLET TRAILBLAZER

225,000 MILES • 4.2L • V6 • 4WD • AUTOMATIC

CORNYCORN

MEMBER
1 POST

I was driving down the highway doing about 65 and noticed temperature gauge starting to rise, that was early this morning. so, I pulled over to let the truck cool down added fluid and went on my way. it's has been 3 or 4 times now overhearing the truck seems to run fine but here the past couple days when I start truck it's shudders a little then shuts off. I have to do this like 3 times before the truck stays running and runs fine... any ideas would be greatly appreciated, thank you..

Aug 29, 2023 at 2:04 AM

STRAILER

✓Experienced Mechanic
55,248 POSTS

It sounds like you could have a blown head gasket, but can I ask when the engine is overheating. can you hear the radiator cooling fan working? If not, I would check the fan fuse #20 under the hood, if so, let's do a head gasket test by following this guide:

https://www.2carpros.com/articles/head-gasket-blown-test

This guide may help as well:

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Here are the wiring diagrams for the cooling fan so you can see how the system works. Check out the images (below). Please let us know what happens.

Image (Click to enlarge)

Professional Diagram for 2CarPros Members
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Aug 29, 2023 at 10:20 AM

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