tlorenzo

hello all. my daughter has a 2004 4runner 4.0L. Long story short while she was driving it, it was pressurizing the coolant system and blowing out the coolant from overflow jug. Then pressure in the system cracked radiator and daughter over heated vehicle and she bent valves on cylinder 1 & 5. So got both heads reworked and new valves installed. DNJ head gasket kit. Finished job like month ago and shes been driving it ever since no issues. 2 days ago she calls me and said over flow jug was empty when she checked it that morning. i let it cool off and topped off coolant to normal levels and started vehicle. instantly coolant was rising and overflowing out the open radiator. couldn't believe it. I did compression test and 4 were @ 200psi and 2 were @ 190psi. when i checked compression on cylinders 4 & 6 coolant was overflowing out top of uncapped radiator.I pressured tested coolant system and pumped it up to like 17psi and it held steady at 17psi for couple hours. Does this sound like head gasket needs replacing again? Normally i'd say instantly head gasket bad. But since i just done it, it's got me stumped. Wondering what else could it be is driving me crazy. really dont want to pull head off if i dont have to. replaced water pump when i did head gasket. Didn't replace thermostat tho. Thanks in advance. ted

ksti

I'm not familiar with your motor, so I will use the basics.
You spent some time replacing the head gaskets and water pump, the thermostat is a given, especially for the cost of one unless you boil tested it.
Also did you re-tourque the heads if the manual calls for it?

tlorenzo

hello, thanks for the reply. yea i was gonna replace thermostat other day after i got done doing compression test. i started testing on right side. when i did the final 2 is when it kinda let the air out of me. checking other 4 no reaction with coolant sitting at bottom of neck of radiator. Cylinder 4 & 6 when doing compression test coolant fluid would rise and overflow out of radiator. Big differance those 2 compared to the other 4 as far as coolant fluid reaction. manual doesn't say to retorque head bolts. done deal after you do the few steps. but i was thinking about torquing them another 45 degrees to see if helps. thanks again ted

ksti

First of all, are you using a FSM ? (Factory Service Manual)
What are the readings on the compression test? (the numbers)
Silly question, but was the radiator cap off while you were doing the test?
Just sounds like your not testing properly or I'm missing something.

tlorenzo

Cylinders 1&5 is 190psi . The other 4 were at 200psi. Yea i have a FSM. i thought it was cyl 4&6 but its only cyl 6. Compression from cyl 6 is leaking threw to coolant system. I gotta pull head back off, no way around it. Dont know if something i did (pretty sure not) or if the DNJ gasket had a failure? Wanted to ask members here about which head gasket is best to use on 4.0L V6? I read alot of people saying to use original toyota brand. But lately been reading alot of people recommending to use FEL-PRO head gasket on toyota 4.0L motor. Also any tricks y'all like to share when you do head gasket job I'd appreciate it. Thanks again