ok really need a direction to go, got a 91 4runner with 3.0L. keep getting coolant to spurt out of the radiator cap, doesnt happen all the time, truck doesnt overheat just does it at random times. I have replaced the head gaskets, radiator, thermastat and 3 caps. Did a block test and it passed, compression test was pretty even on all cylinders (150 psi). Only part that has not been changed is the water pump is it possible that this could cause this issue?

 

Do you have an over flow tank hooked up to the radiator ?, if so is it hooked up properly ?.

I had an 85 toyota truck that would over flow every time I turned it off. It turned out that the previous owner hooked up the over flow tank backwards, so once I figured that out and hooked it up right it stopped

 

Good Idea checked that and its good

 

So you do have an over flow tank hooked up to the radiator ?. If so, how full are you keeping the over flow tank ?.

 

I do have it connected it takes fluid out and sometimes into it but I lose about a quart or so a week. So I try to keep it around the full mark on it.