Thanks for the info. Are the FEL-PRO 8726PT gaskets the good ones everyone is using? I thought there was a blue Felpro gasket that was being used, these seem to be grey. I am probably thinking of something else.
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Blown head gasket or something else?
- Thread starter Don-T
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Now I have another question. I was moving the heads around on my workbench taking sensors, block-off plates, injectors off and one of the pre-chambers fell out. I thought they were pressed in? It literally fell out on the bench. It came from the driver's side head, second from the back. I wonder if it was loose enough to allow for a leak to get around the sealing ring in the head gasket? That is the side the steady stream of small bubbles was coming from.
CARC686
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Penetrant florescent dye and a pair of yellow shades is how we did this kind of inspection in aviation (looking for cracks).
CARC686
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I don't know anything about blue head gaskets. There is another part number for this truck from FEL-PRO that's a hundredth over-thickness for if you've had your heads milled. That P/N is FEL-PRO 9128PT
The pre-cups are supposed to be a light press fit. I have seen a center punch used to improve the fit of the cup. Pick two spots outside of the fire ring of the head gasket just outside of the precup bore and mark two indentations with the center punch. This will retain the precup.
I dropped the heads off at a machine shop yesterday. They called a while ago. There are no cracks anywhere in either head, good news. They are however, warped 0.004". Not too bad. They are going to take off just enough to get the heads flat again. They also said all the pre-chambers need to be staked so that will also be done. The shop has a guy that can check the injectors as well so they can get that done. Since the shop has to disassemble the heads to clean and surface them, they are going to put to valve seals in. I just ordered the gaskets from RockAuto so as soon as I get them I will drop the seals off at the shop so they can assemble the heads. Hopefully this will take care of the problem.
cucvrus
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You are doing the right thing. But still buy new torque to yield head bolts. No studs are needed. I have driven these trucks hundreds of thousands of miles in stock form with no issues using the stock parts. Good Luck. Have you looked at the rear main seal? Just asking while you have it this far apart.
I have ordered new head bolts. I see no reason for studs on a stock engine. along with the gaskets. I wanted ARP bolts as I have always used them on gas engines but I can't find any so I ordered Felpro. All the gaskets are Felpro as well, as that is all I have ever used.
It does not appear that the rear main seal is leaking fortunately. I hope it stays that way. Is it possible to change it without pulling either the engine or transmission?
I am using my engine hoist for pulling and installing the heads. I am thinking about cutting the heads off of a couple of the old head bolts to help with setting the heads without damaging the gaskets. I figured I could cut a screw driver slot in the top of the bolts to remove them. Any thoughts on this?
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You could, but honestly the bolts will stick up and get in the way of setting the heads down onto the pins. Just need to be gentle when you set the heads down on top of your gaskets...
I have honestly seen zero proof that ARP studs perform better than TTY bolts. If the bolts are not TTY then studs may perform better. Has anyone confirmed that 6.2 head bolts are actually TTY? Torque angle and TTY are not synonymous. I believe the head bolts on the 6.2 are torque angle and not TTY.
As for guide pins, you don't have room for them. You're going to struggle to fit the driver's side head between the break booster bracket and block. Just slide the head across the dowels until it drops into place.
As for guide pins, you don't have room for them. You're going to struggle to fit the driver's side head between the break booster bracket and block. Just slide the head across the dowels until it drops into place.
cucvrus
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Just Google 6.2 diesel head bolts and there are pages explaining one time use stretch head bolts torque to yield . I used the Felpro bolts on everyone I ever replaced the head gaskets on. You should be golden. And the pegs on the block will assist in setting the heads down. And to answer the question on the rear main seal it can be changed with the engine and transmission still attached in the truck. Good Luck.
The GM service manual mentions cleaning and applying sealant to the bolt threads which implies reusable.
I think the confusion comes from this other paragraph. GM wanted the bolts replaced with a new longer bolt, not because the bolts are TTY.
I think the confusion comes from this other paragraph. GM wanted the bolts replaced with a new longer bolt, not because the bolts are TTY.
It sounds as though the original may be reuseable, but the new bolts are cheap. I am putting in new ones. Good info though.
cucvrus
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I have the same book that I received after my second class on the 6.2 diesel. I have an older one also. I used to go to Moorestown NJ for training at the GM school. I guess the part I remember was that on warranty repairs we threw the head bolts away and used the new ones. I just kept that train of thought for the past 40+ years and do it every time. Really inexpensive in the grand scheme of things. The first 6.2 diesel engines were boat anchors better than the 5.7 but about as poor and the shop was full of trucks needing work for engines head gaskets and injection pumps. Back when you could make good flat rate pay the more jobs you done. 
So yes you can use the old bolts. GM recommends they be replaced. Good Luck I think you got this. Read the part about putting one bolt in the head before setting the head on the pegs.
So yes you can use the old bolts. GM recommends they be replaced. Good Luck I think you got this. Read the part about putting one bolt in the head before setting the head on the pegs.While we are on the subject of head bolts, what do you use to be sure you get an accurate 90 degrees rotation on the last turn of the head bolts when you are torquing them down? My torque wrenches are for ft. lbs., they don't do angle of degrees. Another question, do you do the 20 and 50 once or twice? I did the 20 one time. I did the 50 then stopped. I decided I don't want to guess at the 90 degree rotation. I am going to recheck the 50 ft lbs before I do the 90 degree rotation when I get something to do that with. I am shut down until then.
cucvrus
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90-degree torque angle adapter or just set the torque wrench to 15 minutes on a clock face and turn it to 30 minutes. Understand. An extra 1/4 turn basically.
Thanks, I guess my OCD is giving me some trouble with this. I like torque wrenches, no guessing. I ordered a torque angle adaptor in 1/2" drive but the head bolts closest to the fire wall may not allow the use of it. I guess I could mark the head of the bolts and make a best guess but I hate to do that. What about going over the head bolts again at 50 ft lbs before the final 90 degree turn? I think it might be a good idea.
That sounds like a plan for the hard to get to bolts. Thanks.