QuestionWhat is the proceedure for replacing the thermostat in a 1993 Chev S-10 pickup (2.8L V-6). Is there any advantage to using an aftermarket thermostat that operates at a different temp?
AnswerHi Jimmy,
First, make sure the engine is not HOT.
Next, you can drain some coolant, and prefferably catch it for recycling purposes, and make sure no animals or kids drink it.
Next, remove the bolts in the upper radiator hose neck on the engine. The thermostat is under it. Observe the direction the thermostat is installed, because on some engines the thermostat can be accidentally installed backwards, and it will NOT work properly.
Better yet, know the correct direction for the new one, and make sure it is installed that way.
If your old one had a gasket, be sure ALL of the gasket material is removed from both the neck, and from the housing. Some use an "O"ring, which is much easier.
Don't "goop" the new gasket with permatex, silicone, or any other sealer. If the instructions that come with your replacement thermostat say use some sealer, then use just a very thin thin thin layer.
After installing it, slowly refill the system with coolant mix.
Here is the only tricky part. You want to make sure you don't trap a large air pocket in the cooling system.
In reality, I usually add coolant to the radiator while the thermostat is out, untill it comes up from below inside the thermostat housing. Then I install it, then add some more coolant.
The air will migrate to the highest point in the cooling system, and if that happens to be the heater core, You might want to remove athe highest heater hose, and add coolant till no more air comes out.
Chevies with the return heater hose going directly to the radiator tank usually purge the air out there, so after filling the radiator, keep the cap off, and look down inside the tank. Start the truck, and you should be able to see the coolant returning through the heater hose.
I keep the cap off and run the vehicle till the upper radiator hose noticably gets warmer, meaning the thermostat has opened, and coolant is flowing through the system.
Now...I see no reason normally to install any thermostat other than what the manufacturer recommends.
If you are having an overheating problem with a normal thermostat installed, then there is a different problem.
The tubes inside the radiator are plugged with mineral deposits. Look down in there while the coolant is drained.
The airflow through the radiator is restricted by dirt, grass, bent fins, etc.
The fan clutch is not operating properly.
The water pump is not moving coolant properly.
Or there is some other cause of excess heat.
1. Plugged exhaust system.
2. Blown head gasket or cracked head.
3. Slipping transmission.
4. Extremely rich or lean fuel mixture.
5. Severe overloading.
Or the gauge might be wrong.
Van
