Strange oil problem

[LSXsierra02]

I have a problem that has been leaving me scratching my head. I have an 02 gmc sierra with 190,000 miles. The problem I am having is when I drive the truck for lets say 30 minutes, check the oil, and its has gone down 1/2 to 1 quart of oil. However when i let the truck sit for a day it fills itself back up to its original oil level. I have great oil pressure, there is no oil leaks, theres no smoke coming from the tale pipe, and I have taken the drivers side valve cover off to replace the PCV and everything looks clean with no oil buildups. Im not sure where my oil is hiding at. Any help would be much appreciated.

[KARNUT]

I have a problem that has been leaving me scratching my head. I have an 02 gmc sierra with 190,000 miles. The problem I am having is when I drive the truck for lets say 30 minutes, check the oil, and its has gone down 1/2 to 1 quart of oil. However when i let the truck sit for a day it fills itself back up to its original oil level. I have great oil pressure, there is no oil leaks, theres no smoke coming from the tale pipe, and I have taken the drivers side valve cover off to replace the PCV and everything looks clean with no oil buildups. Im not sure where my oil is hiding at. Any help would be much appreciated.
[. Not unusual to have a change in oil level between hot and cold, they always say check cold. A half a qt difference in oil level to a qt is normal. There my be build up somewhere holding oil back. Your could be a little over concerned because of the mileage.


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[Jsdirt]

Yeah, that's normal - when the vehicle sits all day, all the oil that's in the top end (under the valve covers, in the rockers, lifters, and in all the passageways in the engine) drains back down into the pan. If you check your oil then, it's going to be much higher than if you check it immediately after shutting it off at the local gas station. That's true of any engine with a pressurized oil system (anything with a oil filter), and a wet sump (oil pan) oiling system. 

 

Sounds like you're probably a little low on oil to begin with. I always check oil first thing in the morning, before starting it for the first time. Get the oil level right to the full mark ( PARKED ON A LEVEL SURFACE !! ) then, and you'll be fine. After running it, and checking right away, it will probably appear to be halfway into the crosshatched area of the dipstick, since a couple quarts are up in various parts of the engine.

[Doug_Scott]

Try waiting 5 or 10 minutes before checking oil.  

Manual says check oil at operating temperature.  If you check it cold it will be half a litre low, but when at operating temperature it will be full.  Most dipsticks will either have a hot and cold full lines, or a checkered region that indicates an acceptable range. 

It is normal for it to take a few minutes for all the oil to return to the pan.  Any longer than 15 minutes is too long.  Engines are not designed internally to capture and hold oil, it serves no purpose to store a litre of oil that is not under pressure. If the rocker covers/top of cylinder head is holding oil, it will leak past valve seals and into intake or exhaust ports and be burnt. 

A litre is a lot of oil.  Hold up a litre bottle up next to the engine and try to imagine what could be retaining this as being normal. 

I think if you simply wait 15 minutes after shutting engine off you will find it far closer to full. You could even just wait 5 or 10 minutes and see it as being near or full.