Strange engine oil level readings

[mshac]

Drained all the oil out of the rear engine and changed the filter. Before draining, rear oil level read near 8 qts. Let oil drain overnight, so hopefully got every drop out I could.

I added 6.5 qts based on advice I've seen here, and experienced with other motors. Started the engine, got good oil pressure readings, it ran smooth, so I shut it down.

I checked the dipstick, and the oil was showing near 4 qts. I thought it would come up in few moments so I checked it again later, but still barely over 4 qts!

No oil has leaked out. In fact I cleaned the engine after the oil change. Its spotless. Why do I read 4 qts when I put in 6.5 qts???

Logic would say its the wrong dipstick, with incorrect markings. If that's true, then the 8 qt marking would be more like 10.5 qts - no wonder it was blowing out oil!

I caught all the old oil in a jerry can, so I could measure it if needed.

My next step is to verify the PN on the dipstick, but have any of you ever experienced anything similar?

[Jhogan0101]

I think the reason is because the original engines didnt have oil filters they had screens.
The oil filter is taking up the difference.

[mshac]

Originally Posted by Jhogan0101

I think the reason is because the original engines didnt have oil filters they had screens.
The oil filter is taking up the difference.

That occurred to me. but I don't think the filter can hold 2.5 qts of oil, can it? Also, I checked the TSIO360 engine manual, and it shows the oil filter adapter and oil filter as original design equipment. By 1978, I believe Continental was putting oil filters on most engines from the factory.

[Jhogan0101]

Maybe check and see if both dipsticks are the same. Cant imagine you have 2 that are incorrect.
I would go with whats on the dipstick.
I now keep my naturally aspirated engines at 6 qrts instead of 8.
Much happier w 6 now.

[mshac]

Originally Posted by Jhogan0101

Maybe check and see if both dipsticks are the same. Cant imagine you have 2 that are incorrect.
I would go with whats on the dipstick.
I now keep my naturally aspirated engines at 6 qrts instead of 8.
Much happier w 6 now.

Thanks for the tip Philly - I agree no need to always run full of oil. Maybe on a long cross-country, but that's about the only time I can think of I'd want full oil.

[fsnewton]

Same here. I realized after the first two oil changes (and after removing lots of oil from the AC belly) that the dipsticks weren’t calibrated. We put in 8 quarts and it reads 6 quarts. Before that I thought my engines were “burning” oil but it seems it’s just been blown out the breather tube. I use the 6 quart mark now (knowing that I filled it with 8) until I can get the dipstick calibrated.