Yellow 13 said:
This thread should be 7MGTE BHG problems. The GE's headgaskets almost never blow.
The only ones I have dealt with were GE's actually.
can shed some light on exactly why this happens to this particular I6 engine?
It isnt anything with this particular engine. Ever hear of the the Ford Taurus, Dodge Neon, Toyota 4 Runner, etc? All have the same design. As mentioned by somebody esle in this thread, and thousands of other times it gets asked, the engine is an iron block and aluminum head. Two dissimilar metals joined together. Much like a circuit breaker or turn signal flasher. Those two items are designed to open up when heated. The two different types of metal heat and cool at different rates, just like the engine. The sheering forces are too much for the factory asembly when subjected to overheating. A composite gasket will have some give, so it is utilized. Now overboost was never intended for the car either. So 58 lb/ft will hold it in place. Detonation was not intended when the car was forced to inhale significant increases in pressure.
I don’t think I have seen one post regarding the actual cause of this problem.
Surely you jest.
Especially at the rear of the motor where the down pipe routes with the 1st CAT on a stock pipe...this is where the heat is the greatest.
Except the blow on GE engines without the precat, in the rear, when low on coolant. It becomes the hot spot on the block.
Chicken and Egg scenario... which came first
Together actually. The chicken like all animals was created with all of its eggs it would ever have already inside. Pretty much answers that one, doesnt it.:biglaugh:
I blew a GE's hg! I modified the air intake, the car ran lean, + bad 87 gas, + 100 degree day
I have done something very similar, but also leanded out the air flow meter.
And as already mentioned many many times, after the first BHG, improper repair simply lead to another, and another, and another. And as already mentioned many many times, torque, tuning, and cooling, and you will be fine. Or leave it totally stock and just maintain. I know Dr Jonez and IJ must get tired of repeating themselves.
most stock HG failures I've seen at at the #6 or #5 cylinders. On the other hand, I'm not an auto engineer...feel free to raise the BS flag
No need. All I have seen that were not modified first are the same way from the bimetallic design, and the hot spot at the rear when low on coolant.
Toyota revised the headgasket after several failures, but never issued a TSB or Recall.
Toyota revised many parts that never failed. Trying to make something better doesnt mean the first one was all wrong and should be free. I have done plenty of free Toyota headgaskets on the 4Runner campaign. The headgasket itself was no good. So they were done for free.
