'09 5.3 No oil pressure. No oil. No sign of leak.

[PatDTN]

Could you be so low on oil that there's just enough in the pan at startup for the pickup to suck it up and pump it into the motor, but the level drops when it sucks it up so then the pickup is no longer submerged and can't suck up any more, so the pressure drops?

Yeah, that's what I'm assuming. Haven't gotten down to the garage today. Honeydos kept me busy.

 

[PatDTN]

I finally got to look at my Tahoe. Looking under the hood I can see a couple of hoses going around the right side of the radiator. They're wet with oil but aren't those transmission cooler lines? There's enough dirt mixed in that I couldn't tell if it was oil or tranny fluid.

Sliding under the truck I thought I'd found my oil. But no, that turned out to be from my front differential. The bottom of the engine is dry. No leaks from the valve covers either. The front of the engine is dry...

I finally drained the oil, swapped on a new filter, and refilled. I was surprised at how much oil came out. Also at how bad the oil looks. I'm thinking I missed a change which I only do every 5000 miles.

I'll examine the oily hoses later. For now my cold has turned into pneumonia and I'm beat.

Thanks for all the great help as usual !

 

[OR VietVet]

If you have hoses entering the radiator on each side of the radiator then you have an oil cooler. If just one set of hoses, then no oil cooler and those are trans lines. Sounds like you may have leaks at hoses that seep over time and you may have also missed an oil change. Shame shame.

 

[PatDTN]

If you have hoses entering the radiator on each side of the radiator then you have an oil cooler. If just one set of hoses, then no oil cooler and those are trans lines. Sounds like you may have leaks at hoses that seep over time and you may have also missed an oil change. Shame shame.

Yeah, 10,000 miles on an oil change might be pushing it a bit far on an engine with 220k miles and still running AFM. I'll do better I promise.

I'll take another look to see if I have an oil cooler but I'm pretty sure I'd have seen that this time.

 

[ppvtahoeguy]

Let's use the my KISS principle "Keep It Simple.... Stupid."

#1 Is the oil full? Top it off...if it is dirty, change it.

#2 Does the motor have internal oil pressure? If the valve/cam lifters and rocker arms are tapping after more than 20 seconds after start-up then you have little to no oil pressure. Cause: Bad oil pump or oil pres. relief valve in oil pump....replace whole pump.

#3 Does the motor get hot fast due to low or no pressure or tap only when hot. Replace oil pump.

#4 If it doesn't tap or run hot when warmed up.... then you need to replace the oil pressure sending unit and the screen underneath it located at the top/rear of the block. Do both and you may also need the wiring harness pig-tail if that appears damaged. This is a common issue.

I sell Police Tahoe PPVs & Suburbans and have don this a few times in my 38 years in police cars. https://www.youtube.com/channel/UCsT8PtAE_v5rIp02grMhrhA

 

[BG1988]

I'll examine the oily hoses later. For now my cold has turned into pneumonia and I'm beat.

Thanks for all the great help as usual !

might be covid19 get tested if you have not yet.

 

[PatDTN]

Let's use the my KISS principle "Keep It Simple.... Stupid."

#1 Is the oil full? Top it off...if it is dirty, change it.

#2 Does the motor have internal oil pressure? If the valve/cam lifters and rocker arms are tapping after more than 20 seconds after start-up then you have little to no oil pressure. Cause: Bad oil pump or oil pres. relief valve in oil pump....replace whole pump.

#3 Does the motor get hot fast due to low or no pressure or tap only when hot. Replace oil pump.

#4 If it doesn't tap or run hot when warmed up.... then you need to replace the oil pressure sending unit and the screen underneath it located at the top/rear of the block. Do both and you may also need the wiring harness pig-tail if that appears damaged. This is a common issue.

I sell Police Tahoe PPVs & Suburbans and have don this a few times in my 38 years in police cars. https://www.youtube.com/channel/UCsT8PtAE_v5rIp02grMhrhA

Thanks. I already found I was just way low on oil. Way low was just the point where when I started it up I had enough oil to build oil pressure. Shortly after that there was enough suspended in the cylinder heads that the oil pump wasn't picking up.

I drained the oil after inspecting the outside of the engine for signs of leaks and refilled it with fresh oil and a new filter. It looked like I got nearly 4 quarts out I was surprised to see. Since that I've put about 100 miles on it with no more issues. Driving shows about 40 psi of oil pressure on my gauge.

My motor does have a constant tick. If I ever find some money I'll probably replace the truck. I've got a vibration I can sense from the front end. I also noticed an obvious oil leak from my front differential. I'll top that up but if I'm feeling the vibration it's probably already damaged.

 

[PatDTN]

oops. Double posted a reply

 

[iamdub]

Thanks. I already found I was just way low on oil. Way low was just the point where when I started it up I had enough oil to build oil pressure. Shortly after that there was enough suspended in the cylinder heads that the oil pump wasn't picking up.

Could you be so low on oil that there's just enough in the pan at startup for the pickup to suck it up and pump it into the motor, but the level drops when it sucks it up so then the pickup is no longer submerged and can't suck up any more, so the pressure drops?