Overheating

Tiny
SUMMER529
  • MEMBER
  • 1994 CHEVROLET S-10
  • 4.3L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 150 MILES
I replaced my radiator and my water pump and after I did that the truck is overheating and blowing out cold air
Sunday, January 27th, 2019 AT 4:57 PM

15 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good evening

It sounds like you have air in the system.

https://www.2carpros.com/articles/car-heater-not-working

What have you tried to bleed the system?

https://www.2carpros.com/articles/engine-cooling-system

Why did you replace the radiator and water pump?

Roy
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Sunday, January 27th, 2019 AT 5:58 PM
Tiny
SUMMER529
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My fiance replace the radiator and water pump because the coolant was leaking from the bottom of the truck somewhere and we couldn't figure out where it was coming from and it was not overheating and so we deciphered where the leak was coming from which was the water pump and now that those have been changed and he put water into where the coolant goes and turn it on and drove it for a minute and it started overheating
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Sunday, January 27th, 2019 AT 6:04 PM
Tiny
ASEMASTER6371
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OK, it sounds like the system needs to be bled.

Have him let it idle until the thermostat opens. Have him add coolant as needed. Once the thermostat opens, run the engine at 1200 rpm and turn on the heater. Have someone watching the coolant level and add as needed. Once you get heat, the air is out of the system and you can install the cap.

Roy
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Sunday, January 27th, 2019 AT 6:09 PM
Tiny
SUMMER529
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Thank you!
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Sunday, January 27th, 2019 AT 6:13 PM
Tiny
SUMMER529
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  • 24 POSTS
He says it overheats before he even gets the heater turned on and it only takes a couple minutes before the heater to turn on and he wants to know does he let the truck stay running
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Sunday, January 27th, 2019 AT 6:16 PM
Tiny
ASEMASTER6371
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When it starts to overheat, the coolant level should drop and he can add coolant. If not, then the thermostat may not be opening.

Did he replace the thermostat?

https://www.2carpros.com/articles/replace-thermostat

Roy
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Sunday, January 27th, 2019 AT 6:19 PM
Tiny
SUMMER529
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No he has not
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Sunday, January 27th, 2019 AT 6:28 PM
Tiny
ASEMASTER6371
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Then he needs to start there.

https://www.2carpros.com/articles/replace-thermostat

Roy
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Sunday, January 27th, 2019 AT 6:43 PM
Tiny
SUMMER529
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Thank you
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Sunday, January 27th, 2019 AT 6:47 PM
Tiny
ASEMASTER6371
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Your welcome

Always glad to help

Roy
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Sunday, January 27th, 2019 AT 6:50 PM
Tiny
SUMMER529
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May I ask you some questions about my about my Lexus LS400
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Sunday, January 27th, 2019 AT 7:29 PM
Tiny
HARRY P
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  • 2,293 POSTS
I tend to agree with Roy. You need a new thermostat. Costs about $10 at the local parts shop, takes all of 2 minutes to replace. A bad thermostat would cause the pressure to build in the cooling system. A weakened part, such as an old water pump or radiator, may crack and start to leak before the pressure builds enough to go out of the radiator cap and into the overflow reservoir.

Go ahead and replace that thermostat. While you're at the parts store, borrow the cooling system pressure test gauge and use it to check for other leaks. I suggest this because at 150k miles on this truck, it's pretty common for the lower intake manifold gasket to have hardened and start leaking coolant into the intake, which lets it get into the combustion chambers and potentially cause other issues.

How to pressure test a cooling system: https://www.2carpros.com/articles/radiator-pressure-test

Good luck on that. As for the Lexus, please start a new thread for it here: https://www.2carpros.com/questions/new

Thanks for using 2carpros
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Sunday, January 27th, 2019 AT 8:52 PM
Tiny
SUMMER529
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Ok so backing up a few responses, when I told him what you said before you decided on the thermostat needed changed, he said he added coolant and before he even turned the truck on it was leaking. Does he still start the truck and let the truck run for a min? And should it still be leaking?
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Sunday, January 27th, 2019 AT 9:26 PM
Tiny
ASEMASTER6371
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No, you need to find the leak with a pressure tester. That needs to be addressed along with replacing the thermostat.

As for the Lexus, you need to start a new question. Site rules only allow one vehicle per question.

Www.2carpros. Com/question

Roy
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Monday, January 28th, 2019 AT 2:26 AM
Tiny
HARRY P
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Tell him to make sure that the drain plug on the bottom of the radiator tank nearest the passenger side is closed completely. Turn it clockwise, like you're tightening a screw.
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Monday, January 28th, 2019 AT 3:52 AM

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