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timjet · 03-31-2017, 05:47 AM

New to me Dec '06 build date ISL 400 hp. I called Cummins and confirmed the oil capacity - 28 qts including oil in the filter.

Before changing the oil I checked the dip stick and it showed oil level about 3/8 inch above the Full line. I drained the oil from the pan and let it drain for about 30 minutes. I set aside 28 qts of oil. I filled the new oil filter with oil, it took almost 4 qts, but not quite and installed it. I reinstalled the oil drain plug and poured the remaining oil into the oil fill tube. I now have a measured 28 qts of oil in the engine. I started the engine and let it run for a minute or so and verified good oil pressure. Turned off the engine waited about 5 minutes and checked oil level on the dip stick. It was like before about 3/8" above the Full mark on the dip stick.

I drained as much of the old oil out of the old filter as I could and then measured all the oil that was removed and it came to 24 qts. I wonder where those remaining 4 qts are? I know I didn't get all the oil out of the old filter, but there wasn't 4 qts remaining in it.

watersupply · 03-31-2017, 06:15 AM

You probably had a couple quarts still left in the turbo. 5 minutes after shutting down is not enough time to let everything drain back down into the oil pan. Just my 2 cents worth.... [emoji106]

mackwrench · 03-31-2017, 07:32 AM

Turbo doesn't "hold" any oil. My guess is the oil cooler, small amount in oil supply line to turbo, residual in engine, small areas in top of cly head and oil filter all add up to your difference.

timjet · 03-31-2017, 03:06 PM

Sounds right, I wonder if I've overfilled it now.

D Lindy · 03-31-2017, 04:12 PM

Engine AND transmission dipsticks on coach's are notoriously in accurate. You filled your system with Cummin's specified amount of oil. I'd let the engine set over night and then pull the stick and where the upper level of the oil is mark that as full. This is also why Allison says to only use the key pad to check trans fluid levels because of the inaccurate dipsticks. These dipsticks are installed by the RV mfgr. based on the radiator confiruation etc, that Cummins has no idea about, so Cummins/Allison install generic dipsticks knowing they'll be changed at the RC factory.