Hey guys, I was wondering what causes a head gasket to blow? I replaced my head gasket on my 95 4Runner a year and a month ago, and it gave out on me again. It blew out when it han about 143,000 miles on, now 16,000 miles later(159,000) it blows again!!! It has never over heated on me since I replaced it the first time. I drove to lunch fine, then when I got out of lunch I went to turn it on and all it did was click twice, then started fine. But after i backed out of the parking lot, and was about to get on the street, a bunch of white smoke came out of my exaust. I pulled in to the parking lot next to it, open the hood and checked the radiator, and sure enough, it was low. So im more than sure its my HG. This FREAKEN SUCKS!!!! So back to my question,what causes it to blow?

 

I'm assuming that you're talking about the 3.0. Did you replace the head bolts during your first repair?

 

I'm in the same boat. I've got the 3.0 and losing water fast. Looking forward to learning as to why, I just bought mine, so I can only assume that the previous owner got it hot before.

Chicken, I understand that it is a must to use new bolts when replaceing the heads. I'm curious as to why this is so important?

 

Yeah, I did replace the head bolts.

 

The head bolts from the factory are torque-to-yield. Once they stretch, they don't go back.

Mike in AR

 

Really? Is this the case with the 22re as well? Did I screw up bigtime by reusing my head bolts?

 

Nope, your OK reusing 22RE bolts

 

*phew*!

 

Good. Two more questions: What brand of gasket did you use ? Did you check for head and block warpage?

 

The headgasket issue on the 3.0 is caused by the stock exhaust manifold and crossover pipe superheating the rear driverside of the engine (can't remember which cyl # this is). Headers alleviate this problem.

 

Jasper uses these on their "remanufactured" engines. I heard that these are the new gaskets that Toyota uses. Is it? Whether or not, have 3.0 owners had good experience with them?


From the Jasper website:

GRAPHITE HEAD GASKETS:pliable material that does not tear when casting
expand and contract. Graphite gaskets transfer heat evenly and will
not deteriorate around water passages like Kevlar gaskets do.

 

I cant remember, I think they were the ones from O'reillys. I also had my heads machined.

 

Bump...

 

My 1993 just blew the head gasket. I am preparing to change, but while I am in there I was thinking of some performance improvements such as performance valve grind and rv cams along with new injectors. Any ideas on what to do to the heads and fuel injection upon head gasket replacement?

I was just driving home with ac on and suddenly the truck shuddered and white smoke came billowing out of her, then she started to over heat. When I got her home and she cooled off I noted very little water in the radiator or at least what I could see. I didn't see any leaks on the outside. Any idea where typical head gaskets blow?

 

Are 110% positive it's the head gasket? check the freeze plugs as well

 

White smoke was billowing out of the exhaust pipe and the engine ran horrible till I think I ran out of coolant. It was real cold outside a couple days ago so I don't think she overheated, but was definitely on the verge. I just got her running tight. Additionally about a year ago I noticed a slight stumble/misfire with slight throttle, which would disappear when more throttle was given which I am thinking could be an injector or valve problem/valve spring problem. I am thinking of doing a valve job and giving her new valve springs. Or can other better heads fit oh her?

 

get the heads pressure tested and the surfaces machined flat from a good machine shop. and while the heads are off, if you want, replace some springs and valve stem seals. but as far as the valves themselves, if they hold good pressure when its tested, run them. a good machine shop will tell you what to do. as far as the injection, now would be a good time to replace injectors or have them rebuilt. and i've heard on the #6 cyl is where the problem usually is. not sure about better heads. like they've said before, aftermarket headers seem to solve the problem. also if you ran out of coolant, have the block surfaces tested for straightness. get a true straight edge and do it yourself with a set of feeler gauges. do it twice diagonally on once straight across. slide the feeler gauges under the straight edge and see if the block is flat. if its warped you're gonna want to pull the motor. and if that's the case you might as well rebuild it imo.

 

Any tips or tricks when pulling the heads? What about entire motor? I was totally psyched when I bought the car since it didn't leak anything, pulled tight and had the head gaskets replaced by the dealer as a factory defect. Toyota must have used a real cheap head gasket as I have never blown a head gasket even with a high comp SBC that was abused. I hope I don't have to rebuild her. I will if I have to since she's worth it.

 

if you have the resources, id pull the motor first and put it on an engine stand. it makes everything easier. if not, there's threads on here. i have a 22re, and i blew a head gasket. i replaced it without taking the motor out. it was a real pain. wish i would have just taken the motor out. i got everything fixed and on start up spun some bearings, so im saying screw it and putting a fresh motor in it. and chances are toyota didnt use a cheap head gasket. the 3.0 wasnt considered their best design. by the way when you replace the head gaskets, go to the dealer and get some o.e.m gaskets. also be meticulous about prepping the surfaces, making sure they're flat is a must. new head bolts, drop the pan and inspect your crank/bearings. dont spin them on start up like me. bu sure everything is nice and oiled. im sure im forgetting some other stuff, but those are just basic tips.