I have a 93 Toyota 4 runner that I had to replace the head gaskets on do to the recall work over torqeing the headbolts. After replacing the gaskets I can't run it with the thermastat in with out it over heating. I put a new water pump,radiator, and thermastat in to since I had it apart. I can run it without a thermastat at a normal temp. without over heating. What could be the problem?

if the job was done properly , re-torquing the head bolts is not necessary
what is very necessary however is to clean out the stud holes and threads before refitting the head and applying thread lubricant to the stud threads
the problem is when there is oil or water left in the holes before fitting that muck creates a false torque reading
the setting is reached but the head is still loose so re-torquing the studs will sill cause that hydraulic lock situation and the head will still be loose
also all head studs are not always the same length so a stud will bottom out at tension but again the head will be loose
and lastly, head gaskets have a sealant applied that glues the head to the block on operating temperature and that will now be destroyed by the oil and water
all of this is explained in detail in the workshop mmanual

if the headbolts were not torqed to the sync pattern or the intake manifold was torqed in sync it will leak water into ur crank case , whoever did the job have the run a compression check on ur engine and lets hope you dont have a cracked cylinder

Is there a question ?

Go to You Tube Video, to
see how the job is done

That is a very reliable motor
thru 1995 only,not so much after
with 4.0

The head gaskets blow out due to the head bolts pulling out of the block resulting in stripped threads on most of the holes in the block, there is no recall even though this is a known problem, Toyota did fix some of them under the normal power train warranty of 5 years/60,000 miles. There are several videos and instructions on how some people fixed this problem without replacing the engine block. In any case it's a very expensive repair,.

was the head machined? if not the head is bent and is causing the water to leak into the crank shaft

it could be going out the exhaust when youre driving and you wouldnt know it was happening

Did you replace your overdrive cable on the throttle body assembly?

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_62314e5b2470e8b5

further to this.... if the battery has side bolts but no actual bolt heads it is probably an allen key or torq socket you will need to disconnect it.


Robert

I've had mine blow twice on the EFI 3.0 engine. Toyota came with a beefed up gasket. Make sure that is the one they are using.