2nd gen overheating! (Need help)

[Connor]

I have a 1994 4runner sr5 3.0 4wd with a 2 inch lift and 33 by 12.5 tires. About 1000 miles ago I replaced the head gaskets with mls ones, replaced radiator, water pump, timing belt, thermostat, fan clutch, and even put in an electric flex a lite fan. My 4runner is still over heating when going up hills. I have tried two different new thermostats and even took the thermostat out all together and it still gets hot. The coolant is great and has water wetter in it. I just don't know what it could be! People have said it could be the heater core but my heater works like a champ so I don't think that's it. The coolant level stays the same so it doesn't have a leak. Oil and oil filter just changed, same with tranny fluid. Only thing I could think of is the larger tires without a regear. I just don't know!

 

[94_4runner757]

Any luck?

 

[cap10]

Wow ! With all that work done you should be making ice cubes ! I would check how much water your motor is pushing through its system when running at a idle. Remove your thermostat and take off one end of the return hose to your radiator and place it in a large bucket. Put a garden hose in the top of radiator and turn it on just enough to keep up with the discharge. Then you should be able to tell what is going on. If you dont have a blockage in your block or head someplace it should have a good flow.
If that does not tell you anything I would check the tranny for a overheating problem.
I am sure that when you had your heads off you made sure everything was good right? Its easy to miss a small crack for instance unless its done in a shop. You would be able to do a leak down test and find that of course.
I have never owned a automatic . I wonder if Toyota has a one way check valve in the tranny line like a jeep does? I have heard of those getting stuck before. Anyway, If there is anything else that comes to mind I will get back at ya. Good luck

 

[RonJR]

Could have an air bubble in the cooling system, in which case it needs to be "burped". 2nd gens are notorious for trapping air inside the cooling system and causing temperature fluctuations and/or overheating after you think you've completely refilled it after engine work.

Park on a steep hill with the front as high as you can get, take off the radiator cap, and let it idle for a while, adding water as you are able. Turn the heater on max. Usually takes 30 minutes or so to get all the air out.

 

[OzSurf]

Guys this is from 2014... :doh: