So my 1990 4Runner with the 3VZE and an automatic transmission blew a headgasket on a rebuilt engine.
So it took me a few years to get the engine back in and get it running because of health problems. I have been in contact with the rebuilder, but I'm not asking for recompense because the rebuild was over 5 years ago. Anyway, the rebuilder did want me to keep track of the torque required to break the bolts loose and they were all only 20 about foot pounds according to my old bending style torque wrench, so I'm not sure how accurate that thing really is, but those bolts all came out very easily. I expected to work at it, but the bolts holding on accessories were on tighter. As I understand, they would initially go to 33 foot pounds, then two rounds of an additional quarter turn, so clearly they were never set properly from the beginning.
The blown gasket was on the left bank, so my thought was to leave the other side alone. Now I'm not so sure. Certainly now is the time to deal with it, but at the same time "if it ain't broke don't fix it." My thought is I should at least check the torque on the other side, but I'm not clear what the actual torque would read after the proper procedure. I expect them all to be just as loose, so should I just torque them all, or start over?
The next question is whether or not I should replace the head bolts, since they weren't torqued all the way, will it matter?

Thank you in advance.

 

Last year when I did the head gaskets on my 3vze I used my torque wrench to tighten the bolts the additional half turn past the initial 33 fr lbs. They went to about 65 ft lbs and yielded a fair amount in the process. A lot of people re-use them successfully though. I think I would take them all out and run a thread chasing tap through all of the holes a few times and them proceed from there.

 

Don't use a tap!

 

That's cool. I have a set of thread files, but I didn't know you could buy those thread cleaning gizmos, but I have made stuff like that for cleaning threads out before.

On the torque to yield bolts, am I understanding correctly that it deforms the bolt slightly when it reaches the proper torque? If that's the case, then can they be cleaned up and re-used and would that not skew the torque values anyway?

 

You do not have "torque to yield" bolts. (Don't confuse torque to angle with torque to yield.) There is a Toyota TSB that says you can reuse head bolts. Of course, at the time of the TSB they weren't thinking of 31-year old head bolts, so if it will help you sleep at night, replace them. In the big picture they aren't that expensive.

 

Cool beans, thanX. As they were so loose, I don't think the bolts were even strained at all, so I'll re-use them. I did pull the head after I started this thread and found the damaged part of the head gasket. I don't know for sure if it was caused by loose head bolts or not. I'm glad I caught it when I did. It started out very slight, so I started for home and four miles later I was in the driveway and knew for certain what it was. Here's the damage So far as I can tell, there are no cracks or other problems, but I'll clean it up this weekend and see what else there is to see.

Thanks again, I've come to rely on this forum for a lot of detail. When I was into automotive repair, I was a Chevy guy, but I've forgotten a huge amount since those days.

 

Thread chasing tap. Do use it. It’s a specific tool made just to clean and straighten threads, not to cut new ones. Run it up and down the holes until you can spin it in with your fingertips. It cleans crap out of the holes and is your friend for getting good torque results. Use lots of oil and blow the holes out with compressed air as you go, of course. You can get one just for the 3vze engine headbolts. I think I got mine from Jegs if I remember right.