How Much Oil Really?

[Flavor 987S]

Originally Posted by stephen wilson

I would guess 1-1.5 Quarts. I'm curious as to why you would want to know that?

Mainly because I just switched oils. Went from Mobil 5W50 to Joe Gibbs DT40 5W40.

I am just curious how much old oil is still in the system.

To compare, I've heard on my 993 Turbo, that when we do an oil change there, we only get out about 10 quarts. There are several quarts of old oil that remain in the system.

[stephen wilson]

Oh, I assume you're wondering if it will affect your UOA's? I have no idea on that one!

[san rensho]

Originally Posted by Flavor 987S

Mainly because I just switched oils. Went from Mobil 5W50 to Joe Gibbs DT40 5W40.

I am just curious how much old oil is still in the system.

To compare, I've heard on my 993 Turbo, that when we do an oil change there, we only get out about 10 quarts. There are several quarts of old oil that remain in the system.

Completely different system, the 993 is a dry sump design which retains a lot of oil in the lines, cooler etc. Box is a wet sump that retains very little. When I do an oil change, I use about 9-1/2 quarts on refill after about a 1/2 hour drain when completely hot. 9-1/2 is what the manual specs.

[Flavor 987S]

Originally Posted by thstone

Oil capacity is 9.5 quarts.

Oil change with new filter requires 8.7 quarts (oil filter itself is 0.2 quarts) (both numbers from owners manual)

Therefore, a little less than 1 quart remains in the oil cooler and internal engine passages.

8.7/9.5 = 92% of oil is changed (with new filter)

Originally Posted by san rensho

Completely different system, the 993 is a dry sump design which retains a lot of oil in the lines, cooler etc. Box is a wet sump that retains very little. When I do an oil change, I use about 9-1/2 quarts on refill after about a 1/2 hour drain when completely hot. 9-1/2 is what the manual specs.

Thanks, guy! Much appreciated.