Did all the searches on this site along with google searches.

I have a 93 Navajo 4x4 4.0 V6
I have been driving it with two blown head gaskets for almost a year Having to replace the spark plugs every month or two from getting rusted out. It woudl still run great just start to miss from rusting out the plugs. Always kept it topped off with coolant/water and oil which is started to eat at the rate of one quart a week...leaking into the cooling system thru the heads.
All this time the coolant temp would go from halfway to cold and back up constantly. Figured it was the blown heads since this is common with blown heads.

I just had it all fixed. BOTH heads were cracked. It ran to the H on temp gauge more than once so I figured they would be bad. The gaskets were so eaten away the the water pasages in the Intake manifold were corroded and enlarged past the gasket so I also replaced the Manifold. New water pump, new thermostat new radiator cap. ALL new gaskets top to bottom.

Well, oil stays toped off never uses any now. Coolant is still fully topped off and green. BUT the coolant temp still goes from halfway to COLD. Up, down, up, down. Constantly. And this is NOT the temp gauge. You can feel the heater output going from hot to cold.

System has been burped. Went thru that 10 times just to make sure. She is topped off. Up to operating temp let cool then check Radiator level.

HELP!

 

looks like you got good ones from exlorer forum . com

 

Replace the therostat.

Chris

 

Thanks but, been replaced twice as has the Heads, Intake, and rad cap.

 

Replace the t-stat AND try a difft manufacturer.

 

Could try replacing the temperature sending unit.
Greg Sanders

 

Trouble is that it is not just the gauge that is reading crazy, the temp of the heater output shows that it is getting hot then cold.