My truck started doing this a while ago. It showed near empty every time I checked it while getting fuel, but after sitting for longer than a few hours; it would read full. Recently it reads totally empty while fueling, but reads full after sitting. It is the 07 in my sig. I change the oil and filter every 5k and use rotella. I have had the truck since it was new and it now has 164k on it. Any help or thoughts would be appreciated. Also, has anyone used that motor flush stuff that you run for 5min and drain to clean things out? thoughts on trying that?

 

So were is the oil getting stored? In the valve cover? Take the cap off and look in there!
NOT normal and wierd! It's all gravity drain back to the pan! So unless someone stuffed rags in your oil fill this is a good one!

 

I have no idea, but I have looked in the valve cover with no luck. It has been doing it for a while just reading low. This is the first time it read that there was no oil. I was thinking sludge and do a motor flush, but some people say to stay away from the motor flushes. Maybe some additive in my oil? It runs great and the pressure is normal so I'm going to keep on trucking...

 

Are you sure you are not just mis-reading the dipstick? I hate the crappy dispstick in my '07 and took me awhile to figure out how to read it. It is quite difficult for me to see where the oil level is hot. I just only check it cold now.

 

My oil is dirty so it is easy to see. Right after I change it is the only time it is difficult. I wish that was the case. I'm starting to worry now. I hope someone chimes in with an opinion on doing a motor flush...

 

Yeah throw some marvel mystery oil in it or some ATF 2 qrts run it 10 minutes and change the oil!

 

I'll try that this weekend and let you know if it helps.

 

Update: Marvel Mystery Oil is AWESOME!!! I put that stuff in after changing the oil (10 quarts of motor oil and two quarts of Marvel) as per the instructions and after less than 100 miles of driving and it shows correct on the dipstick. My fuel economy increased almost 1mpg too.

Nadir, maybe try it and see if it gets easier to check. The dipstick is white on my truck and it is really easy to see. Maybe you have the same thing going on. If I only checked it cold; I would have never even noticed.

 

This happens on Cat motors too. After you shut it off, some of the crankcase pressure stays in the dipstick tube, pushing the oil down. When you take the dipstick out it releases the pressure.

 

I check my oil by removing the dipstick, wiping it off, reinserting it and then pulling it back out to check. I have let it sit at a truck stop for over 15min after removing it and still nothing on the dipstick. After I put the Marvel oil in it reads true every time so I am guessing sludge was built up somewhere.