Engine Overheating

Tiny
MRBLAZIER
  • MEMBER
  • 2001 CHEVROLET TAHOE
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 169,000 MILES
My Tahoe starts to overheat when idling with the a/c on, but its fine when the a/c is off or while driving. When idling with a/c on and it starts to overheat I can rev the engine to 1000 rpm or more and it will cool back down. I have replaced the thermostat and coolant but still no luck. HELP!
Thursday, August 7th, 2014 AT 10:15 PM

24 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
First, make sure the coolant is remaining full and pressure test the system if it is losing any. If no coolant loss, I would suspect and issue with the fan clutch.

Here is a guide and a video to help you fix the problem

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

and

https://youtu.be/N_-MLVlBHk8

Please run down these guides and report back.

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Friday, August 8th, 2014 AT 2:41 AM
Tiny
MRBLAZIER
  • MEMBER
  • 6 POSTS
Replaced fan clutch dident help. No coolant leaks either
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Monday, August 18th, 2014 AT 5:12 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
How hot is it actually getting?
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Monday, August 18th, 2014 AT 5:15 PM
Tiny
MRBLAZIER
  • MEMBER
  • 6 POSTS
The gauge usually is right in the middle but I, ve only let it go to the 3/4 mark which I believe is 235
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Monday, August 18th, 2014 AT 5:21 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
No, 3/4 won't be that hot. 235 would be in the red.

If it only overheats at idle, it has to be either an issue with the fan or possibly the water pump but that would be rare.
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Monday, August 18th, 2014 AT 5:26 PM
Tiny
MRBLAZIER
  • MEMBER
  • 6 POSTS
Well in the middle is 210 and the gauge only goes up to 260. Since I've already replaced the fan clutch and the fan is in good condition guess I have to replace the water pump.
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Monday, August 18th, 2014 AT 5:32 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
We generally do some testing before throwing parts at it. There are way to determine if you are getting circulation.
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Monday, August 18th, 2014 AT 5:37 PM
Tiny
MRBLAZIER
  • MEMBER
  • 6 POSTS
How do I test for proper circulation? What other testing do I need to do?
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Monday, August 18th, 2014 AT 5:42 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Sometimes you can see into the radiator cap and see irt flowing out of the tubes or you can rig up some type of clear section for the radiator hose.
You can disconnect the upper hose and run the engine to see it flow but you have to keep the radiator full and the cold water will tend to close the T-stat.
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Monday, August 18th, 2014 AT 5:47 PM
Tiny
MRBLAZIER
  • MEMBER
  • 6 POSTS
Update, apparently the fan clutch I installed was bad, I tried an AC Delco unit worked perfect FYI.
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Monday, August 18th, 2014 AT 5:49 PM
Tiny
CARMEN N OSCAR
  • MEMBER
  • 2 POSTS
  • 2000 CHEVROLET TAHOE
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
Desperately need help! I changed the thermostat and water pump and still overheating. I did notice the hose on top going to the radiator has no pressure so I opened it with the vehicle running and nothing but air. I have seen in previous post to bleed the cooling line, but unsure of that. Please help with any information. Thank you!
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Tuesday, April 30th, 2019 AT 1:36 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
When the air released did the coolant level drop?
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Tuesday, April 30th, 2019 AT 1:36 PM (Merged)
Tiny
CARMEN N OSCAR
  • MEMBER
  • 2 POSTS
Yes, it dropped. I also felt the top hose and was hot to the touch and the bottom hose was cold.
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Tuesday, April 30th, 2019 AT 1:36 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
The thermostat was put in correctly not backwards?
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Tuesday, April 30th, 2019 AT 1:36 PM (Merged)
Tiny
MYBARBIEWORLD
  • MEMBER
  • 5 POSTS
  • 2000 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
2000 chevy tahoe overheated always putting water and anti-freeze in it daily. Any help
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Tuesday, April 30th, 2019 AT 1:36 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
If you haven't replaced the thermostat-do so and see what happens and let me know-could be other things such as the radiator, water pump and headgasket/cracked head or block and airlock
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Tuesday, April 30th, 2019 AT 1:36 PM (Merged)
Tiny
MYBARBIEWORLD
  • MEMBER
  • 5 POSTS
I think it may be the waterpump. Because its also making noise when I press on the gas, its lecking out fast as I put the fluid in. So my husband gonna try the waterpump first. Then I will be back with results. Thank you
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Tuesday, April 30th, 2019 AT 1:36 PM (Merged)
Tiny
MYBARBIEWORLD
  • MEMBER
  • 5 POSTS
Okay we change the water pump and the temp is 210 and higher but the good thang is that no more lecks. So our next step is the thermostat be back with more results.
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Tuesday, April 30th, 2019 AT 1:36 PM (Merged)
Tiny
ESTRONG83
  • MEMBER
  • 2 POSTS
  • 2000 CHEVROLET TAHOE
  • 160,000 MILES
My truck is over heating I changed water pump, thermostat, intAke manifold gasket, vvalve cover gaskets And still it over heats idle for ten mins then in 5 minutes it's red lining it also keeps pushing coolant back into overflow container. And now the heater blowe cold
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Tuesday, April 30th, 2019 AT 1:36 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Check for a blocked radiator, also best check for a blown head gasket as well, start here.
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Tuesday, April 30th, 2019 AT 1:36 PM (Merged)

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