Overheating

Tiny
JUSTIN L HALL
  • MEMBER
  • 1989 CHEVROLET 1500
  • 5.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
Okay, so here is my problem. The truck was doing fine in terms of circulating the heated coolant but then all of the sudden after I replaced the lower hose on the radiator it started overheating. The top hose was cold as ice and the bottom was warm. I am not sure what I did wrong. Help?
Thursday, April 19th, 2018 AT 5:33 AM

4 Replies

Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
You may have an air lock in the cooling system or the thermostat has failed. Try re-bleeding the cooling system, and it that is okay look at the thermostat.
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Thursday, April 19th, 2018 AT 5:49 AM
Tiny
JUSTIN L HALL
  • MEMBER
  • 2 POSTS
How do I bleed the cooling system?
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Thursday, April 19th, 2018 AT 5:49 AM
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Run the engine with the coolant filler cap off, as the thermostat opens up any air trapped should come to the surface it will bubble away and you may see the coolant level drop. If you can get the front of the car a bit higher jack it up or drive it up onto a gutter this can help as the air will want to make its way to the highest point, watch the coolant and if it drops just top it up so it is safe and you can see any bubbles. When the engine fans come on it will be at temperature and the thermostat should be fully opened. Feel for cool spots on the radiator check for good heat at the heater and make sure the temperature gauge is sitting where it normally would be. If this is all okay you should have all the air out of the system. It is always good to recheck the next day as small air pockets can still bleed out and the coolant level may drop a little over night, see how you go doing this.
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Thursday, April 19th, 2018 AT 6:12 AM
Tiny
MIKE H R
  • MECHANIC
  • 3,094 POSTS
After you have tried what MHP said and it still has a problem then I would change the thermostat.
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Thursday, April 19th, 2018 AT 10:46 AM

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