lilninja

so after changing out the camshaft sensor(because had oil setling in it) and the throttle position sensor(because cel said it was bad) i unhooked batt. and reset the cel. all was good on the way home, no cel or anything untill about 30 miles in to my trip when the temp gauge started to skyrocket!./ i immediatly pulled over n shut pearly down to allow to cool and popped the hood to investigate. immediatly i seen the coolant resivor bubbling and pulled the cover to see that it was pushing steam into the tank :/ i believed it was a thermostat issue, so i changed it and directly after pulled the water outlet housing cap (upper radiator hose cap) off so i could "burp" any air behind the thermostat out. it bubbled for a while then quit then bubbled a while again and quit. spitting here and there on and off. when i put the radiator cap back on and drive it overheats. with it off its fine... any ideas on whats wrong?? no white smoke out the tail pipe at all... 1994 es300 with 1mz-fe

JSM

Did u check the oil to ensure there is no water going into the pan? Wondering if instead of getting burnt its going straight into the pan.

lilninja

have not checked yet and if there is water in with oil then head gasket.. not ready for the cost of geting heads pressure tested though. i think average here in wisconsin is about 150 each and then starting repairs. maybe it is time to sell parts and move on but i have no savings toward another car at the moment. my 4 month old daughter has to come first. which leavs me immobilized at the moment

randal

For starters, you could begin pulling spark plugs to see if any look unusually wet with coolant. My #6 cylinder plug was most definitely different (and wet with coolant) indicating a gasket leak. The rear plugs are not as easy to get to so I would do what you can without tearing the plenum off.
Are you completely sure that w/o a radiator cap, the engine runs cool? If so, that would mean depressurizing the cooling system helps. I am wondering if the water pump is not getting 'weak' , unable to circulate coolant when back-pressure is added.

lilninja

yes sir. i ran for over an hour in park with cap off and didnt budge over half heat on the guage. next time i make it back out to mom n dads where it started giving me issues ill check the plugs.

1987

is the coolant mixed to the right ratio? too much water to antifreeze will lower the boiling point...

lilninja

would that cause the above listed problems?