I have an overheating problem again with my truck. Last summer i replaced the hoses, water pump, thermostat, rad, got it flushed. I have been mudding since then but not for about 6 months. The thermostat leaks a little and I have changed it twice and still leaks. Could it just be that, because today I am going to get a new housing for it and thermostat again. Since it has a paper gasket should I put gasket sealer on both sides or one. Because I just put it on the bottom side of gasket. Could it be the heater valve? I know it is not the heater core because i do not smell radiator fluid inside the cab.

 

Are you sure you're putting the stat in right side up ?
Don't laugh , I've seen it done by 'pros'.
The stat should fit in a recess on the block side with the gasket on top.
Make sure the surfaces are completely clean of old gasket , even a tiny piece will cause it to leak.
You shouldn't need sealer.
Also after refilling the radiator , park facing up on an uphill grade.After it cools a bit remove the rad cap and top off again.When filling on level ground an air bubble forms in the top end of the engine so it is not completely filled.
When cold does the fan turn by hand with a slight resistance or does it freespin easily ?
If you can spin it with one finger and it continues to turn for a moment , time for a fan clutch.

 

if its leaking, yes that can be your issue. the system has to be sealed to be able to build up pressure in order to raise the boiling point of the coolant.

 

Thats my problem i put the gasket on the bottom of thermostat because i saw the groove in the housing so i thought the thermostat went on top.

 

Already replaced the clutch when i did the water pump cause had to take it off so i replaced it.

 

Usually the stat housing has High Temp RTV Silicon Gasket sealer. That could be the problem you are having.