i have a 1995 4runner that i just rebuild the engine in and when we put it in the truck it would over heat or get hot so we thought that it was because of the thermostat so we replaced it and then again it gets hot not a clue why so i tried to look up why and i kept seeing fan clutch, "you need to replace your fan clutch" so i did and it is still getting hot does anyone know why or have any ideas cause I am about to run this truck off of a cliff!!! CAN SOMEONE PLEASE HELP ME!!!!!!!!!!!!!

 

Check your radiator cap.
Check your top and bottom hose for binding or weakness.
Also try a flow test on your radiator.
Check your oil and radiator fluid for contamination.
These trucks are known for having incorrect gauges, does the needle act weird on start up? like does it do anything but stay at cold when you start it,, jumping around going too the middle then back anything like that?
Is your fan put on your fan clutch backwards(really hard to do but possible.)
temp sending unit could be telling you it is hot when it is not, is it showing any other signs of being too hot other then the gauge?
Lastly it could be your water pump.

 

are you sure theres no air in the system? You have the heat on right?

all the hoses in the right spot?

if the coolant flows well through the rad, what about the air that cools it? is your rad plugged with dirt and bugs?

Did you forget a rag in a coolant hole in the engine while it was put together?

 

schnayke-
i just put on a new radiator cap and new hoses, the radiator was just rebuilt by a local radiator shop and they said that it flows really well and they went through and fixed and messed up fins,I will check the fluids but there shouldn't be anything in the fluids because its all new but you never know so ill check that, the guage stays at cold for a while when you start it and then gradually rises to hot and after it sits for a little the radiator overflow starts to bubble like its almost boiling.

nothingbetter-
i tried to burp the system best i could and the heat was on when i did his too, all the hoses are were they need to go, the radiator was just gone through, and no i made sure that when i put every thing on that it was all clear.

 

I vote Fan clutch. when you spin your fan ( with the truck off ) does it just free spin or does it have some resistance?

 

it has resistance

 

Well bubbling can be bad. It may indicate you have a gasket that didn't seal well or was blown already. I think it is the head gasket that does that. I never had the problem but recently with my cooling issues I came across some info about bubbling in the coolant. I guess it can happen without mixed fluids. Try looking it up.

 

okay ill see what i can find

 

How's your tranny running? When's the last time you serviced/flushed it? That could also be your source of heat....although it is uncommon.

 

it runs perfect and we just flushed the fluid in there too.

 

Could it have to do with my heater system?? cause my dad thinks that there my be corrosion in my heater system that could be blocking water form circulating. Does this sound like a possibility??

 

Also it's possible to put the headgaskets on the wrong sides and blocks coolant ports. Seen it personally on a junkyard 3vze.

 

yeah well i sure in the hell hope that, that isn't the case! lol

 

Check the water pressure... Is the system holding pressure? Tbh I would not get my radiator refurbed, just buy new, that is a relatively important part of your cooling system...unless it was working before the rebuild...

 

well i didn't have $300 to spend on new radiator and yeah i believe so

 

Well my point is that if it wasn't overheating before hand look at the only things that have changed... 1. Radiator 2. Engine .....x2 on HG backwards blocking the water jets..... You didn't give info on before the engine rebuild...

 

well i don't know how it ran before because when i bought it had a blown head gasket

 

Also did you check the block and heads for straightness? Did you get new headbolts, they're TTY (torque to yield) and must be replaced or they won't torque properly? Did you torque them properly, using the proper method?

 

yeah everything is strait that i know of and yeah they were replaced and we used the correct torque pattern

 

Do you get heat when you run the heater? If so then I would suspect it isn't a blocked heater core. although that is just me thinking through the problem. I don't know that info for fact. I bet a search on here will bring up a test to show if your core is clogged or not.