2007 silverado 4.8 over heating on idle

[Peterramirez7475]

Hello All,

Im new to the site and was wondering if i can get some info on my problem. I recently had the heater hose leak and I replace it never did my temperature ever go over 210 but now it does just past the zero on the 210 but then the fans come on and goes back to normal, i bled the system over and over then flushed the radiotor replaced the thermostat twice and the coolant sensor once and still the same problem, but what I notice if I keep the AC on my truck never over heats stay right at 210. Now Im going to replace the both serpetine belt and tensioner see if that will fix the issue but does anyone know what it may be causing it????

[Raptordude]

It's probably a solenoid or something that actuates your fan is intermittently failing (these fans have clutches, they aren't electronic so there may not be any solenoids) if that's the case, your fan clutch may be going out. I'm not terribly familiar with the fans on silverados

 

In the Jetta I have, it has electric fans that always run when the AC is on, and are actuated by a sensor and solenoid to turn on when they need to. Just something to think about

 

 

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Edited April 21, 2017 by Raptordude

[Peterramirez7475]

I have Electric fans no clutch fan, on some forums they say there is a low speed and a high speed low speed only turns on at a certain temperature and the high speed comes on when the AC is on.

[Raptordude]

Correct. In my Jetta, the fans come on low speed with the AC on, and high speed when the motor needs cooled. You have a wiring issue. Find the thermoswitch and jump the connections with a paper clip to see if you can get high speed to run

 

 

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[Silverado4x4]

Sounds like you still have air in the system it can be tough to get out sometimes or flushing the radiator you could have plugged some of the radiator veins , you did put the right degree thermostat in?

Edited April 22, 2017 by Silverado4x4

[Dnt]

Unless you have recently flushed the system when you exposed the OLD Decool to the atmosphere you have MUDDED it and the only fix is to have the system thoroughly flushed and refilled with fresh coolant. At the same time I would debug the condenser and radiator fins.

[Peterramirez7475]

Hello All,

 

Thank you all for your input, yesterday i replace both belts and the tensioner and same thing happens over heats just pass the 210 mark and fans come on and it will go back to normal at 210, but it was hot here in socal yesterday so i had the AC on all the time driving and not once did it over heat stay at exactly 210 today I'm going to bleed the system and hopefully I will get all the air out. I did flush the radiator with a water hose last weekend but not the whole system if bleeding doesnt repair the problem Im going to take my truck to get a flush.

[Raptordude]

Maybe your thermoswitch is screwed up and triggering the fans at a hotter temp than they should

 

 

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[Peterramirez7475]

Where is the thermoswitch located?

[Raptordude]

I'm not sure on these trucks, I'm going off the knowledge of my Jetta. The concepts are basically the same though

 

 

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