In my 1991 4Runner 22RE engine: I have the stated problem and the search of the solution procedure to start where the rule indicates ...... rectify the seat of the cylinder head, install the new gasket, check clucht fan .. . perfect, new water pump, new thermostat, radiator checked, hose, in perfect condition, no leaks, new radiator cap and ignition timing according to the manual ....... but when you shut the car, listening instant boiling coolant and pass into the reservoir.
In my review of various forum, I was referred to make the so-called t-block test: start the engine and the 30 seconds press the upper hose (which runs from the thermostat to the radiator) and whether notes tense is an indication that there is a leak in the cylinder head to the cooling circuit.... in my case that hose under the pressure test do not observed this situation.
The temperature gauge indicates NORMAL OPERATING! and being seen on the engine, ALL related accessories and the cooling cycle are working according to the rule but something is wrong!.
I would like to thank any suggestions before proceeding to disarm again to start the revision of the cylinder block or head for example to find internal cracks ........................ THANKS IN ADVANCE.

 

got air in the system? Maybe try lifting the front of truck(park on a hill or jack it up) pull the rad cap, start engine, crank the heat (rear heat as well if equipped) and run her, fill rad till all air is out... might take 15-20 min... if ur rig is like mine, and has an attitude, likes to be stubborn, it may take longer...

 

start truck up with cap open. let it run till its full warmed up. while its warming up. add coolant 50 50 mix as fluid level drops