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thermostat slow


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Eric of Pa.
Novice

Oct 31, 2006, 10:15 AM

Post #1 of 6 (2105 views)
thermostat slow Sign In

This 95 Surburban is still confusing me. Now it is pegging the temp. gauge before the thermostat opens. You guys helped me diagnose a plugged heater core, now after two new thermostats (one 195 deg, one 180 deg.) it gets very hot before it will curculate water, after witch it will work perfectt. The really strange thing is while installing the second lower temp. thermostat, the directions said to run engine from cold till warm with the radiator cap off and top off fluid and install cap.Worked perfect without the cap. Next day going to work it did the same thing, pegged the gauge before going to normal water temp. So it seem to work fine without a cap, but won't with cap on. Help. Thanks Eric
P.S. Cooling system is dirty enough to plug heater cores and I am still trying to get a clean flush.


(This post was edited by Eric of Pa. on Oct 31, 2006, 10:25 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Oct 31, 2006, 1:54 PM

Post #2 of 6 (2100 views)
Re: thermostat slow Sign In

If there's still air in the system that will screw it up. Lowering the T-stat's temp is NOT the answer.

I would check that the radiator is full. Also is there a chance these failed t-stats are upside down? Just a thought.

If you are compelled to do another use OE stuff as I can't speak for the rest, T



steve01832
Veteran
steve01832 profile image

Nov 1, 2006, 4:02 AM

Post #3 of 6 (2097 views)
Re: thermostat slow Sign In

I have had problems with a few aftermarket thermostats in the past. Try installing a new T-stat and gasket obtained at the GM Dealership. After installation, run the vehicle with the cap off. When the stat opens, you will need to top off the radiator. Cap it and carefully grab the upper and lower radiator hoses. BE CAREFUL OF THE BELT AND ALL MOVING PARTS WHEN YOU DO THIS!!! The hoses should be the same temperature. If the lower hose is cold and the upper is hot, check for a circulation problem. It could be a clogged radiator or a restriction in the engine. If the coolant is dirty enough to clog a heater core, it can easily plug a radiator as well. But, start with a AC DELCO themostat and go from there.

Steve


Eric of Pa.
Novice

Nov 3, 2006, 6:11 AM

Post #4 of 6 (2072 views)
Re: thermostat slow Sign In

Thanks Steve,
Could explain '' engine restriction" and possable remidies for it. There is a very big diffrence in temp. of upper and lower rad. hoses.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Nov 3, 2006, 10:00 AM

Post #5 of 6 (2071 views)
Re: thermostat slow Sign In

There should be a big difference in upper and lower hose temp which means the radiator got rid of the heat.

Note: When a part proves bad twice go to dealer as Steve said. Reason I said check the level again is some cars need to be driven, stops, starts, turns to get all the air out.

I test thermostats in a pan of water on a stove and watch them work -- especially if they are hard ones to get at, T



junior8
User

Nov 10, 2006, 5:34 PM

Post #6 of 6 (2046 views)
Re: thermostat slow Sign In

also check to see if hose is collapsing to thermostat housing,as i had same prob on 96 z71,soon as thermostat opened,it let enough water flow to drop temp.






 
 
 






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