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Hummer H2For those who like a little more gleam to their Hummer, the H2 offers a similar rugged look as the H1, but as a lower cost, and with more added features, making it almost a massive luxury SUV.
Had oil/filter changed in Sept. 2025, Val, 5w30, full synthetic. Going with oil/filter change with mobil 1, high mileage synthetic. And then see if other steps might be necessary.
Very doubtful its the oil filter. Its the "Oring" for the oil pickup in the oil pan. You need to remove the oilpan & that pickup tube - on the end will be the bad oring which is causing this low oil pressure at start up. This is an extremely common issue on our approx 20 year old engines.
Here is a pic from another GM forum - this is exactly what mine looked like coming out at 180k miles.
You may not like spending the approx $1-2k (or more depending how many oil leaks you fix at same time). BUT - if your rig is a keeper, I would bet this is your issue.
While I would start with a genuine GM oil pressure sending unit change, the o-ring referenced above is such a common issue, it should really be considered as a maintenance item and done regardless.
Well you have the pan off it only takes a minute to pull the oil pressure relief valve out of the oil pump; don't be surprised if you find little pieces of carbon in there keeping it from sliding in and out. It wouldn't hurt to order a +10 psi spring to replace the OEM one that's in there.
Depending on how much credit you find in the bottom of the oil pan will give you an idea if the engine has had regular oil changes throughout its life. You may find the screen at the end of the pickup tube partially plugged, also affecting oil pressure. A new pickup tube is not expensive, often easier than trying to clean the old one.
