oil cap test

[MattM]

Someone mentioned an oil cap test? Removing the cap and setting it on the filler? Also, see if there is smoke, no smoke, or a bunch of smoke?

What exactly is the oil cap test?

Also, is it unusual to use 1/2 quart (synthetic Rotella) oil every 5500 miles?

[taylorking]

Originally Posted by MattM

Someone mentioned an oil cap test? Removing the cap and setting it on the filler? Also, see if there is smoke, no smoke, or a bunch of smoke?

What exactly is the oil cap test?

Also, is it unusual to use 1/2 quart (synthetic Rotella) oil every 5500 miles?

They were talking about blow-by. Did you notice any "smoke"?

[MattM]

After driving my truck for awhile, I pulled in for some fuel. Thought about the previous post and pulled the cap and set it on the filler tube. Nothing happened. Pulled the cap off and saw a little heat/smoke coming from the filler tube. Did not appear to be excessive.

Does that mean something?

[97Beast]

If its nothing excessive then its perfectly normal all diesels tend to have a little blow by.

[Jake]

If there was just a little heat and smoke you are fine. If there is a lot or if it blows the cap off the tube, then youve got a problem. Using a half quart isn't too bad, you might be leaking it. Id say your fine though. If it starts using more than a quart id wanna check into it, maybe do a compression test, but 1/2 aint nothin to worry about.

[dmd]

Half a quart is nothing. Many of the 7.3's will use oil if filled to the top of the hash
marks. I can use 5-quarts if I try to keep it full. If I let it stay in the middle of
the hash it may use a quart in 5k. Has done it since new. I would say if the oil stays
the same there is an issue. There is oil in the blowby that ends up in the intake
tube so oil is lost. If the oil stays the same then that blowby oil is being replaced
by something.