Oil Change Question

[coldstart]

Here's one for you....I used to have an FL-70 with a Cat 3126. The owner's manual stated to check the oil with the engine running(?). This made a difference of about 3 gallons. Now I have a Cummins ISM which the oil change places say takes 10 gallons. I changed it the third time myself and it only takes 7 gallons unless you start the engine and then it takes another 3 gallons. Have I gone mad?

 

[guest]

In a former life, I put in 30 years as a mechanic and NEVER once saw an engine where it was advised to check the oil running. I was taught to let an engine sit, preferably a couple hours before you pull the stick to allow all the oil to return to the pan. I would go by the owner's manual for the right amount of oil for a change.

My International say 7 gallons in the book, and that puts it exactly on the full mark. The only oil level that I know of where you check with the enging running is an automatic transmission and some power steering units.

 

[Weave]

The Cummins ISM has a 10.3 gallon oil capacity, so the shops are right. There are a few engines out there where the oil is checked with the engine running, the ISM must be one of them. Every engine I have seen that requires this method of checking the oil has a large sump area with the rest of the oil pan being very shallow. I think this and where the dipstick has to be postioned has something to do with why the engine has to be running.
-Weave-