Engine overheating

Tiny
SUSAN PHILLIPS
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • 5.3L
  • 2WD
  • AUTOMATIC
  • 213,544 MILES
We have replaced the water pump, the thermostat and the housing. The engine will still overheat. However, if we drive with the heater running, pulling air from the outside, not recirculating, it cools back down. What should I try next to fix my problem?
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Tuesday, July 2nd, 2019 AT 7:28 AM

7 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good morning,

Is the cooling fan running to pull air through the radiator?

https://www.2carpros.com/articles/how-an-electric-cooling-fan-works

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

How many times has it overheated? I am concerned that the head gasket may have been damaged from overheating.

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

Roy
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Tuesday, July 2nd, 2019 AT 7:58 AM
Tiny
SUSAN PHILLIPS
  • MEMBER
I think first I need to clarify "overheating". I may be using the term too loosely. So usually the temperature hovers right below 210. 260 is my max. I've never seen it go above the line that sits directly in the middle of the two, so 235? I'm not sure if that constitutes "overheating" or not, but it's definitely hotter than normal. Is that hot enough to warp the head gasket? And to be honest, I couldn't tell you how many times it's crept up there. Every time I drove it for about a week, then we replaced the pump. It's been about two weeks since then and it will creep up every time I don't have the heat running, unless it's early in the morning and the outside temperature isn't very high yet and it's a short trip. For example, it usually doesn't happen early in the morning on my way to work, but will happen without fail in the afternoons while I'm driving home and the sun is hottest. I'm not sure about the fan but I will check that when I leave work today. Thank you for the information!
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Tuesday, July 2nd, 2019 AT 8:20 AM
Tiny
ASEMASTER6371
  • EXPERT
235 is right at the point of damaging a head gasket.

What temperature thermostat did you use for a replacement?

Did you check the cooling fans?

Roy
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Tuesday, July 2nd, 2019 AT 8:26 AM
Tiny
SUSAN PHILLIPS
  • MEMBER
Sorry for the delayed response. I only see 1 fan, it's pretty large and appears to be dependent on a belt. Is that the one? If so, it's spinning nonstop. The thermostat is 160 . Duralast 37960.
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Thursday, July 4th, 2019 AT 3:57 PM
Tiny
ASEMASTER6371
  • EXPERT
Okay, first, you have the wrong thermostat in the truck. It requires a 195 for the fuel mapping will be correct.

If it still runs hot, I suspect a possible head gasket failure.

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

Roy
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Thursday, July 4th, 2019 AT 4:36 PM
Tiny
SUSAN PHILLIPS
  • MEMBER
Got a new thermostat this morning. We ran all of the suggested tests for the gasket (except the chemical kit) and so far so good! I wish the guys at our parts store knew as much as you. I think we'd have been saved a lot of trouble. We'll swap the thermostat today and let you know how it goes!
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Friday, July 5th, 2019 AT 8:07 AM
Tiny
ASEMASTER6371
  • EXPERT
Sounds like a plan.

Remember, parts people sell parts and are not technicians.

Roy
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Friday, July 5th, 2019 AT 8:12 AM

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