Engine is overheating when you drive it on the highway?

2004 HONDA CIVIC
100,000 MILES • 1.7L • 4 CYL • 2WD • AUTOMATIC
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RANDY1955
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The engine is overheated when you drive it on the highway it is fine but when you get off the highway into town it will get hot fast. It has a brand-new radiator the fans are working the motor only has maybe 20,000 at the most.
May 21, 2023 at 9:01 AM
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STRAILER
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The first thing I would do is replace the thermostat and check for a blown head gasket. Here are two guides to help us with instructions on how to change the thermostat out in the images below:

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

and

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

Check out the images (below). Please let us know what happens.

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May 22, 2023 at 3:16 AM
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RANDY1955
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This car has 150lbs compression in each cylinder the engine runs great aside from getting Hot. I pressure tested it with the dye and no leaks. Okay, the other day I wanted to see if problem was occurring I have been driving it around town only so I drove maybe 15 miles away on the highway and as soon as I got into town driving it got hot and it does not go up slow it goes to hot just like that it has a new radiator and has a new thermostat. So, figure that one out.
May 22, 2023 at 4:39 PM
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RANDY1955
  • MEMBER
  • 71 POSTS
This car has 150lbs compression in each cylinder the engine runs great aside from getting Hot.I pressure tested it with the dye and no leaks. Ok the other day I wanted to see if problem was occuring I have been driving it around town only so I drove maybe 15 miles away on the highway and as soon as I got into town driving it got hot and it does.not go up slow it goes to hot just like that it has a new radiator and has a new thermostat. So figure that one out
May 22, 2023 at 4:39 PM
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STRAILER
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Did you chemical test the cooling system as in the guide? Also does it force coolant into the coolant reservoir? I also have seen the water pump impeller come loose in the water pump which can cause the problem you are having.
May 23, 2023 at 4:39 AM
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RANDY1955
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  • 71 POSTS
Yes, it does force coolant into the reservoir.
May 23, 2023 at 4:43 AM
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STRAILER
  • ✓Experienced Mechanic
  • 55,249 POSTS
It sounds like the head gasket is blown or you have a bad radiator cap.

This guide can help:

https://www.2carpros.com/articles/why-coolant-is-forced-into-the-reservoir

Please go over this guide and get back to us.


May 25, 2023 at 3:20 AM
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