Head Gasket failure with slapping valves 26k after engine rebuild (IS THIS POSSIBLE?)

Tacoverlander

Tacoverlander

Observer
I have a 96 tacoma 2.7 which I had the engine rebuilt about 26k miles ago. It has ran like a top ever since then with absolutely NO issues at all...until over Thanksgiving Holiday while driving down the interstate probably around 2200 RPM, I down shifted to go up a hill. (around 3000 rpm) and as soon as I started to press the gas I heard a slapping sound from the motor. I immediately pulled off the next exit which was luckily right near me. I could tell that it was coming from just under the valve cover. After removing the head I expected to find a bad valve/ spring/seat or all the above. The only thing I could find was a blown head gasket between the 1st and 2nd cylinders. I took the head to get reworked and have all the valves checked for issues and I also took the gasket to the guy doing the work for me (very respected mechanic /machinist). When the work was completed he told me that everything looked ok inside and the only issue found was where the head gasket blew there was a low spot in the head. He also told me that the sound that I heard was probably the sound of the valves slapping shut because of the 2 cylinders fighting each other (due to the blown gasket). While I am relieved that there wasn't any major damage done to the head I am still concerned at why the head gasket would've blown this soon after a rebuild. I baby this truck as much as possible considering it is my overlanding rig and is not a DD. IS IT POSSIBLE THAT I COULD'VE HAD A FAULTY HEAD GASKET SINCE THE REBUILD? What are your thoughts?

Here is a picture of the gasket and block:
Head Gasket.jpg Block.jpg
 
D

Drewskers

New member
Sure it can happen, if the machining was poor, if the gasket was faulty, or things were not put together right.
 
zolo

zolo

Explorer
Just thinking here, but it has been know to happen. The head bolts can stretch. If they were not replaced when the head gasket was replaced the first time its possible the head torque was never correct in the first place which could cause the gasket to blow in short order.

Id replace the head bolts this time around for sure.

Id also use a serious (calibrated/tested) torque wrench and if it calls for torque plus degree use a degree tool to make sure you get it right.
 
Tacoverlander

Tacoverlander

Observer
zolo said:
Just thinking here, but it has been know to happen. The head bolts can stretch. If they were not replaced when the head gasket was replaced the first time its possible the head torque was never correct in the first place which could cause the gasket to blow in short order.

Id replace the head bolts this time around for sure.

Id also use a serious (calibrated/tested) torque wrench and if it calls for torque plus degree use a degree tool to make sure you get it right.
Click to expand...

I was told that the bolts were replaced at the time of the rebuild as well. Either way I just received my gasket kit and new head bolts today. And I stopped by dads this afternoon to pick up his torque wrench which was just calibrated not long ago;) I'm gonna start putting it all back together this weekend. I've heard that 4 cylinder toyotas are bad about blowing head gaskets anyways. Just hope it's not this often.
 
M

mathers420

Observer
Tacoverlander said:
I was told that the bolts were replaced at the time of the rebuild as well. Either way I just received my gasket kit and new head bolts today. And I stopped by dads this afternoon to pick up his torque wrench which was just calibrated not long ago;) I'm gonna start putting it all back together this weekend. I've heard that 4 cylinder toyotas are bad about blowing head gaskets anyways. Just hope it's not this often.
Click to expand...

The 2.7 is not known for blowing head gaskets. It is in fact known as a bullet proof engine.

I overheated mine multiple times in one trip when the rear heater lines on my 4Runner broke on top of a mountain.
After flushing the radiator and bypassing the rear heat, the engine functioned without an issue for another 25,000 kms before I sold it.
 
pnw_chris

pnw_chris

Observer
mathers420 said:
The 2.7 is not known for blowing head gaskets. It is in fact known as a bullet proof engine.

I overheated mine multiple times in one trip when the rear heater lines on my 4Runner broke on top of a mountain.
After flushing the radiator and bypassing the rear heat, the engine functioned without an issue for another 25,000 kms before I sold it.
Click to expand...

I know of two guys running 15 pounds of boost into their rz engines with full stock internals with zero problems. And they don't exactly baby them either. The rebuild must have been faulty. I wouldn't use anything other than a Toyota factory head gasket myself..
TURBO.jpg
 
red EOD veteran

red EOD veteran

Adventurer
Bad gasket, bad bolt, bolt not torqued, incorrect machine job are all possible. Going off the pictures it looks like the bolt to the left of the gasket break was not fully torqued or it came loose. Can tell from the discoloration around that bolt and how the other side is clean.
 
IdaSHO

IdaSHO

IDACAMPER
Having myself dealt with a low mileage headgasket issue on a 2AZ-FE (2005 RAV) I will say that now is the time to do it right.

I dont know about the motor in this thread, but I do know the 2AZ-FE has proven to become victim to stripped head bolts, due to inadequate thread depth in the block.

The solution is to threadsert the block. Again, I dont know the specifics about your particular motor, but it may have a similar problem.


Take the time, do it right, carry on :ylsmoke:
 
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