Re-torque head gasket from 56 ft./lb. to 75 ft./lb. (Good idea or bad idea)

[Randy0223]

I have a low mileage 1989 Supra Turbo (original owner) with a 7M-GTE engine. Everything about this engine is stock. Five-years ago, it was diagnosed with a blown head gasket and I had my local mechanic do the repair.

The brand of gasket used was Felpro head gasket repair “set” model #HS9473PT. Evidently my mechanic didn’t go the stud route but he did install new bolts (don’t know if they’re Toyota OEM or something else).

I came across an Internet discussion concerning this subject and just learned that head gasket failure is very common this engine. Evidently, the Toyota factory torque spec of 56 ft./lb. is inadequate to the job and eventually leads to failure.

As this was an expensive repair, I don’t want to go through this again. I discussed this with my mechanic and, after checking his reference materials, determined the spec he used was the Toyota specified 56 ft./lb.

I checked the current state of this repair using a Uview Combustion Leak Tester http://www.uview.com/ProductDetail.p...tNumber=560000 and, based on this test, there aren’t any leaks. So everything appears to be good for now. But I’m wondering if it makes sense to have him re-torque these bolts? From what I’ve been able to figure out, those in the know torque the bolts to around 75 ft./lb. when installing a new head gasket.

Again, it’s been about 5-years since this work was done and I’ve put about 10,000 “easy” miles on the car since then (current mileage is 53,000). The charge for doing this is minimal (about $200) which is substantially less than what I paid to replace the head gasket, machine the head, etc. (that job was over $2,000).

He’s a good mechanic whom I trust with all my vehicles, but he’s not a Supra fanatic. If he were to do this work, I’m confident he would follow a stepwise process (i.e., progressively tighten these bolts and not all at once).

I thought someone here might be able to clue me is as to potential pitfalls. Bottom line, is this a bad idea? Will I end up doing more harm than good?

Thanks in advance for informed advice!