Occasional fluctuation in oil pressure. Went back in to replace the NAPA oil pressure sending unit with an ACDelco. Figured I'd go ahead and replace the Napa knock sensors while I was in there. Of course one of them snapped off. Snap on to the rescue, pun intended LOL, my 25-year-old screw extractor easily took it out.

I taped everything around it with plastic like a surgeon around a surgical site, followed by the Shop-Vac and a strong magnet. Then rinse and repeat with brake cleaner. Since I was being so thorough I figured I might as well change the oil and filter, at which point I discovered a little coolant in the bottom of the oil pan. About 110,000 mi so I splurged on a set of new heads and replace the head gaskets. Dropped in LS7 lifters. Figured this would be a good time to install a standalone oil cooler for the engine and a tranny cooler also bypassing the radiator. Being thorough and being on a roll, went ahead and dropped the front differential and the oil pan, pulled off the harmonic balancer, water pump and front cover to do a new timing chain set. And inspection of the oil pump I discovered the pressure relief valve sticking. Actually had three little tiny pieces of some sort of grit like carbon near the bottom. New oil pump arriving tomorrow, Melling 295. The 7.35 pushrods are also arriving tomorrow. Pulled the camshaft while I was in there and the front bearing actually looks really good. Almost pulled the motor to replace the bearings and rings till I saw that. Original hone marks still on the cylinders.

I know, just another day of owning a Hummer 😁

 

Yep, my H2 had all that done and more.
You will enjoy it for years to come.

 

Hummer H2 like nothing else cause everything breaks!

 

My knock sensor had broken inside sounded like jingle bell rock. Causing codes to be sent on both.

 

Damn talk about while you're in there lmao

 

I think it's a Hummer thing. You always, always fine one more thing take care of while you're in there

Interesting. The new AC Delco knock sensors arrive and they have loctite already applied to the threads. Debating with myself about removing it and putting some anti-seize instead. I don't think I've ever seen a knock sensor come loose.
And the list for "while I'm in there" as usual has grown a bit. With the access from having the differential out in the oil pan down and the exhaust manifolds off, and the starter out, it's a great time to replace the battery cables and clean the ground on the block. Already did the power steering pump and the hoses the last time I was in there.. LOL.. just to replace the o-ring on the pickup tube
You should have seen my list while I was in there doing the rear main. New torque converter just because. New reasonable heavy duty u-joints. New input and output seals on the transfer case, and hey, it was a great time to put that new transfer case shift motor in. And O2 sensors. Stainless catback dual exhaust.

On the plus side, my 21-year-old never Disturbed exhaust manifolds came out without one broken bolt. But that's only because I dove into it with everything I needed to drill out the broken studs. If I wasn't ready for that, Hummer logic says every single bolt would have broken on me

 

Make sure you remove your O2 sensors before using your impact gun when removing the downpipe from the manifold. The vibration will destroy it all four OT sensors$$$_$$$

 

When your impact gun rated at $1,400 ft lb will not remove one of the nuts off the flange studs on the manifold, I guarantee you that half inch breaker bar with a 2-foot pipe extension on it for torque will snap that stud right off

 

Ditto That.... My Kind of Meck-an- ic. lMAO... Lucky for me I have an O9. The Knock sensors are on the outside of the block also on the 08. Already had one go. Took 5 min to replace both.

You went far far away doing all that work. You must have a Lift and a Big Garage. But now you have a Great running rig that will last. Good Job.!!

 

Fortunate to have space to work on it. 40 ft by 36 ft 2 Bay shop, wood stove for the winter time. No hoist or anything, but four 6 ton jack stands and a lifetime collection of tools. I can't imagine how people afford to pay a shop to get work done.