No oil pressure at start up, 2001 Tahoe

[Rocket Man]

There is no need to replace the oil pickup tube. Just the O-ring is needed that's only like $7, including other costs like oil pan gasket and RTV sealer. So shops want to replace the pickup tube too or is that just what GM likes to do?

Not afaik. I didn’t see a listing for replacing the o-ring so I used the labor time for replacing the oil strainer which should be the same amount of time as replacing the o-ring since they’re basically the same operation. The parts aren’t a major expense here, it’s the labor especially with the hourly shop rate these days.

 

[2006Tahoe2WD]

Excellent writeup/picts/etc. Thanks.
I'm wondering what oil pressure numbers (hot/cold - idle/1000 rpm) indicate that changing the O ring should be considered?

 

[JonnyTahoe]

I replaced my O-Ring last fall. Pressure went from just under 40 to almost 60 cold. Normal Operating Temp at 70 mph (2000 rpm) is exactly 40 psi. My rust free Texas Yukon is a 2WD. I wanted to remove the oil pan to inspect the condition of the lower end of the motor and the inside of the oil pan for sludge build-up. I got lucky everything was surprisingly clean. While the Pan was off I replaced the O-Ring, the Starter and prepped the bottom of the engine block for the new Oil Pan Gasket.

 

[GBF1]

For the past 45k miles my truck has had its oil pressure drop to zero, within 20-30 seconds after start up. It was not the result of a bad sensor as I tried replacing that first, besides, the loud ticking that would almost always follow was a pretty good sign of the problem. If I immediately took off driving, the pressure would stay up, but I had to keep the rpm's up. Once the vehicle warmed up everything functioned normally until the engine got cool again.

I bought an oil pump with the intention of changing it out but a friend told me to just change out the oil sump O-ring instead as usually that is the issue with no oil pressure in a 5.3.

On a 2x4 Tahoe it is very straight forward to drop the oil pan to access the sump and access the O ring. You have to remove the cross brace under the oil pan which is 4 bolts. You also need to remove the two oil pan/bell housing cover bolts (they hold a small plastic shield in place that keeps road grime out the bell housing. You also need to remove two bolts that hold the wiring harness in place. A simple electrical connector on the low oil sensor then you can drop the pan by removing all of the pan bolts.

Once the pan is down there are two nuts that hold the oil sump to the main bearing caps, as well as the small bolt that actually bolts the sump tube to the bottom of the oil pump. I removed the O ring and it was flattened out like a wedding ring, but not cracked or deteriorated. It was very loose when pulling out the tube as well. I put the new O ring on, which was $2 and shaped more like a fat doughnut. It was harder to press the oil sump tube back into place but it was fairly easy.

Scotch bright pad was used to clean the grime from the block where the oil pan gasket seats. I had a bad oil leak forever and the pan gasket was the culprit as it had long since flattened out as well. Once the oil pan was cleaned up and both surfaces cleaned for a new gasket I had the truck back together and running in less than 3 hours.

High oil pressure once again. With 526k miles this is the most extensive "tearing" into the drive train I have had to do, other than a 2-3 shift solenoid going back in the transmission a while back.

Hopefully this thread will help anyone with similar oil pressure issues who thinks they need a new engine, when in reality you can fix it for $60 in parts and an oil change.

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Thanks for this. I have an 06 Yukon Denali and the pressure rarely gets to 40. I understand this fix is more complicated with the 6.2 engine and AWD. Mine has 183,000 miles and still runs well, but I know I need to do this.

 

[Summajet]

For the past 45k miles my truck has had its oil pressure drop to zero, within 20-30 seconds after start up. It was not the result of a bad sensor as I tried replacing that first, besides, the loud ticking that would almost always follow was a pretty good sign of the problem. If I immediately took off driving, the pressure would stay up, but I had to keep the rpm's up. Once the vehicle warmed up everything functioned normally until the engine got cool again.

I bought an oil pump with the intention of changing it out but a friend told me to just change out the oil sump O-ring instead as usually that is the issue with no oil pressure in a 5.3.

On a 2x4 Tahoe it is very straight forward to drop the oil pan to access the sump and access the O ring. You have to remove the cross brace under the oil pan which is 4 bolts. You also need to remove the two oil pan/bell housing cover bolts (they hold a small plastic shield in place that keeps road grime out the bell housing. You also need to remove two bolts that hold the wiring harness in place. A simple electrical connector on the low oil sensor then you can drop the pan by removing all of the pan bolts.

Once the pan is down there are two nuts that hold the oil sump to the main bearing caps, as well as the small bolt that actually bolts the sump tube to the bottom of the oil pump. I removed the O ring and it was flattened out like a wedding ring, but not cracked or deteriorated. It was very loose when pulling out the tube as well. I put the new O ring on, which was $2 and shaped more like a fat doughnut. It was harder to press the oil sump tube back into place but it was fairly easy.

Scotch bright pad was used to clean the grime from the block where the oil pan gasket seats. I had a bad oil leak forever and the pan gasket was the culprit as it had long since flattened out as well. Once the oil pan was cleaned up and both surfaces cleaned for a new gasket I had the truck back together and running in less than 3 hours.

High oil pressure once again. With 526k miles this is the most extensive "tearing" into the drive train I have had to do, other than a 2-3 shift solenoid going back in the transmission a while back.

Hopefully this thread will help anyone with similar oil pressure issues who thinks they need a new engine, when in reality you can fix it for $60 in parts and an oil change.

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That is awesome on the mileage. How often, mileage do you change oil and filter? What brand oil?

 

[2006Tahoe2WD]

Very good write up on the pan drop. Thanks.

 

[Fless]

That is awesome on the mileage. How often, mileage do you change oil and filter? What brand oil?

Who knows? The OP hasn't been on here in 4 years.

 

[InterceptorF]

OK so I did the o-ring on mine at about 200 K miles and now just today, about a year now, it started having the low oil pressure again (296756 miles). This weekend I pulled the odd bank head and replaced the lifters/ push rods/ head gasket/ head bolts due to a bad tick which fixed the tick but now the oil pressure is at ~18 psi. I guess its time for a new oil pump for me. but 500K wow!

 

[Bofiggy]

Based on what I'm seeing online, I would estimate $500.

215K, low pressure issue zero at startup..After 3 seconds starts to climb to 25..idle .....after sending unit and gauge testing.. Im debating to DYI or shop.. was quoted 1100~1500. If they even wanted to do it. yup its time for the oring. no leaks but shop doesnt want to touch it unless the oil pump is changed out. (warrantee).

 

[Sam Harris]

215K, low pressure issue zero at startup..After 3 seconds starts to climb to 25..idle .....after sending unit and gauge testing.. Im debating to DYI or shop.. was quoted 1100~1500. If they even wanted to do it. yup its time for the oring. no leaks but shop doesnt want to touch it unless the oil pump is changed out. (warrantee).

$1100-1500 to do the o-ring…!?? What are we talking about having done?