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1994 S 10 Pickup 4.3 Runs Cold Thermostat Replaced


writerskramp
12-05-2008, 09:16 AM
Replaced 195 Thermostat that was stuck closed with new 195. 4.3 ran cold then, still runs cold now. Covered radiator, still runs cold. Barely above 100 degrees. You can stick you finger in the coolant, it is not too hot to do so. Leak at rear of 4.3 is serious but not terminal. Have not located source. Coolant drips off transmission housing at rear of motor. Intake Manifold Gasket? No oil in water. No water in oil. Engine did overheat while transporting from previous owner do to lack of coolant but not to red line. Radiator appears new or newer and is quite large. Perhaps it is standard equipment. Previous owner stated needing heater core. Core is not the problem of lack of heat. Engine itself will not come to operating temperature. Any ideas? Thank you.

MT-2500
12-05-2008, 11:07 AM
Make sure it is not air locked or low on coolant.

Go another stat and see what it does.
How are you checking engine tempture?

writerskramp
12-05-2008, 12:19 PM
If it is air locked how do you remedy this? Could the leak have anything to do with this? The coolant does seem to circulate and the thermostat open and close as there is a surge of circulation then stops, then starts. Observed with radiator cap off. Whether the coolant is topped off or not there is no change in temp. I check the temp using the temp Gage in the vehicle. You can stick you finger in the coolant while it is circulating with no discomfort. Thank you for your response.

MT-2500
12-05-2008, 01:14 PM
To bleed air remove a heater hose or hose on upper intake.
Does the heater hoses get warm to the touch.
Are you sure the tempt gauge is right.
If air locked or air pocket on the tempt gauge sending unit it will not work right.

If the intake gasket is leaking itbshould be fixed.
It could be making air pockets.
Also you could have a bad new stat.
If all else fails try another one.
Good Luck

writerskramp
12-05-2008, 07:10 PM
Thank you. I'll give bleeding air a try. Will fix ASAP the intake leak if that is where the problem is. I will let you know how it comes out. Thank you again.

MT-2500
12-06-2008, 10:06 AM
Thank you. I'll give bleeding air a try. Will fix ASAP the intake leak if that is where the problem is. I will let you know how it comes out. Thank you again.

You are welcome.
And remember you can get a bad new stat.
Let us know how it goes.
Good Luck

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