wcasey5

I had this issue with my Pontiac montana, it getting hotter after I shut it off. a nwe radiator fixed it but not before it blew a head gasket. My 4runner was doing what yours was doing before it blew the head gasket (sorry, hope your's isn't going). It sounds like you are low on coolant, I would check for abnormal level in the overflow when hot. Maybe change the thermostat back to original.

And with the temp going up when shut off is an indication of a clog somewhere in the system. Originally car engines didn't have water pumps, they used thermosyphon (even farm tractors into the 50's used this method). The natural circulation of coolant, I think this is what happens when you shut off the engine, but if your rad is clogged, or something is preventing flow (like the jiggle valve in the thermostat) it just won't work.

good luck

dimitri

I deleted my post because I completely missed the second page of posts, where you mentioned having changed the radiator. My theory is that this problem, excluding writing it off as "norma" is caused by a "passive component of sorts. The radiator or thermostat or a partial clog were my prime suspects.When the engine is running, the "moving parts" , water pump and the radiator fan are able to compensate and that's why the car doesn't overheat while the engine is running.

I never noticed it before the waterpump and the thermostat were replaced. I also don't often drive , stop and then hop back in 10 minutes later very often.

My latest thought is to get another thermostat from the dealer, compare it with my original one,and the one that is currently installed, in a boiling pot and see if they behave differently.

benja455

I saw a post in another thread about radiator caps and what happens when you use a higher PSI rated cap.

So, OEM is 13 PSI for the 22RE. I had to get a bigger cap when I put in the two core radiator...I didn't even think to check what PSI it was. Well...turns out, the new larger cap was 16 PSI, so I bought a new 13 PSI cap and while it's too early to say with total confidence (only experimented with it twice), I am not having the same temp gauge spikes as I was before.

So...as a recap - the engine does not start hot after bath room breaks anymore (probably because of the new radiator and fan clutch) and it SEEMS like the temp gauge spikes when using HVAC (specifically the heat) have been solved by the correct rad cap.

I'll drive it a little more in the new few weeks and see if it's really fixed. I'll be pretty please, if the problem is really gone - that was the last little gremlin to fix. It will be nice to get to more fun stuff (fixing rear end sag, trail lights, CB radio, improving the bed/canopy).