Oil Pressure on High Mileage 5.3

[sdsuburb06]

Recently purchased an 06 Suburban with 285K miles. I tried finding more details on this within this forum so apologize if this specific topic has been covered, but what kind of oil pressure are you guys seeing on the higher mileage 5.3 engines? The motor and tranny in this vehicle have never been apart so internals are original. Cruising speeds 55 to 70 mph, under 2,000 rpms and my dash oil pressure gauge is reading about 25-30. Stomping on it and getting rpms upwards of 4,000 and my oil pressure gauge will hit over 40. Thanks for sharing any input on this one, Matt.

 

[swathdiver]

It's obviously lower than when new but still way above minimum specs.

 

[OR VietVet]

Welcome to the forum.

My 05 5.3, after warmed up, will have approx 35 psi at idle and if rev to go thru gears will be at 45-50 psi and I have seen higher when really flooring it but was busy enough doing that, that I cannot give an exact psi but I believe is close to 55 psi. mine is at 151k + miles.

Like @swathdiver said, the psi you state is fine.

 

[Donal]

Recently purchased an 06 Suburban with 285K miles. I tried finding more details on this within this forum so apologize if this specific topic has been covered, but what kind of oil pressure are you guys seeing on the higher mileage 5.3 engines? The motor and tranny in this vehicle have never been apart so internals are original. Cruising speeds 55 to 70 mph, under 2,000 rpms and my dash oil pressure gauge is reading about 25-30. Stomping on it and getting rpms upwards of 4,000 and my oil pressure gauge will hit over 40. Thanks for sharing any input on this one, Matt.

If you are in the warm climate south, you may consider a 10W30 oil. Oil contamination is my concern for high milage Chevrolet engines. So the oil you choose should have a high TBN number so the blowby contaminates can be neutralized and then filtered out by the oil filter. Replacing the oil filter and oil often will help keep the lubrication system clean and the valve train loves clean oil. If you change the oil when the display percent indicates oil change time, consider changing the oil fliter at 50 percent and again at oil change. Wix protec oil filters can be purchased in the maintenace pack carton for about 28.00 for 12 filters. Wix PTL51042MP available at most parts store, some stores may not have on hand, but can have in hand next day or so. Not sure if all brand stores will offer the price. Check at OReilly if you need.

 

[Sam Harris]

My ‘03 with 217k was always right at 38 psi idle. Previous owner always used full synthetic, and changed at the prescribed intervals, as have I. After replacing the oil pump, along with a few other things, she’s running 42psi, and climbs to 80 often. Of course the melling hv pump, and my heavy foot have something to do with those higher numbers these days..
I’d say the best thing you can do, other than watching it carefully, is to use high quality oil, and filters, and change often. Being a bit lower on pressure, I’d bet you have some buildup from a previous owner not changing as often as they should.

 

[OR VietVet]

I actually paid attention yesterday and was registering just above 60 psi at 75 mph and cruising.

 

[rockola1971]

You should be seeing atleast 10psi for every 1,000 rpm. Thats what the race cars target use to be. Anything less than that and I would looking for the problem which likely will be a worn oil pump, leaking oil pickup oring or fairly moderate bearing wear and cutting open your oil filter will tell that tale.

 

[olliec420]

You should be seeing atleast 10psi for every 1,000 rpm. Thats what the race cars target use to be. Anything less than that and I would looking for the problem which likely will be a worn oil pump, leaking oil pickup oring or fairly moderate bearing wear and cutting open your oil filter will tell that tale.

10 + 10 per 1,000

 

[Blk00ss]

I would also recommend replacing the oil pickup tube o ring, assuming yours hasn't had it done.

ALL 5.3 and 4.8 as well as others will have this issue. The o ring becomes stiff and somewhat flat sided creating a poor seal for the pickup tube to oil pump. This is a very very common issue. Our '05 with 170K at the time started showing under 40 psi at startup which was not normal. Dropped the pan, pulled the pickup tube and replaced the o ring (which was hard and flat). Started it up, boom 60psi at startup, and usually sits around 40psi at idle

 

[Toenail]

You should be seeing atleast 10psi for every 1,000 rpm. Thats what the race cars target use to be. Anything less than that and I would looking for the problem which likely will be a worn oil pump, leaking oil pickup oring or fairly moderate bearing wear and cutting open your oil filter will tell that tale.

I seen this thread on oil pressure and thought my story might be interesting although it happened many years ago. I purchased a 1984 Blazer with a 305 engine it. It had 68,000 miles when purchased and held about 25 psi when idling and 35 when running around 2000 rpm. The gauge was a little twitchy as was common with those miles. I changed out the sender and the idle pressure dropped to zero. I checked this with a replacement gauge and the idle pressure showed about 3 psi. Highway speed it was about 10 psi. I immediately dropped the pan and checked the bearings. They were perfect and the clearances were tight factory specs. I installed a high volume Melling pump and the idle pressure dropped to 1 psi with road speed pressure about 20. I then read where the high volume pumps hold less idle pressure but move more oil at higher speeds. More tear down revealed that when Chevrolet built the engine they drilled from one main feed hole and it went through the main lifter feed gallery and came out inside the lifter valley.` This gallery is in the center of the engine on the 265/350 series of engines. This gallery feeds both left and right lifter galleries. I placed an aluminum rivet into the 3/16" hole and everything was back to normal with 30 psi idle (standard pump) and 45 psi at highway speeds. I put over 100,000 addition miles on the truck after this repair. This was the days of bad camshafts and this camshaft was perfect with the extra oil feed into the lifter valley. The valve guides were very worn due to the lower pressure feed though the lifters and required Perfect Circle guide seals but no other damage was found from the first 68,000 running at 10psi.