correct way to check for blow-by

[bob00stroke]

Is this the correct way to due a blow-by check? I have a '00 7.3 with 152,000 miles.

1. warm engine fully then let idle

2. remove oil filler cap - most (all?) diesels will have some blow-by vapor coming out of the filler tube but it should not be a huge amount.

3. have someone rev engine slightly - the blow-by vapor should reverse direction and be sucked back into the filler cap, if so, the engines passes the "blow-by check".

If the blow-by vapor does not reverse direction (and can also increase), then engine fails the "blow-by check" and may have problems.

Thanks (my truck passes this test).