How Much Oil Really?
 

2006 Boxster S
6-speed manual

I know the car requires about 8 quarts of oil for an oil & filter change......but in rough numbers, how much oil is in the entire system? Thanks!

It varied over time and evolution of the engine but if you buy 10 quarts you should have enough with new oil filter installed.

Just buy a 12 quart box.

Check your owners manual for the exact amount of your model year.

Thanks, but that's not the underlying issue. I've known for years that 8 quarts is plenty for my oil changes. I've had 8 changes done the past 7 driving seasons.

What I am trying to understand better, is how much "old oil" remains in the system (lines, cooler, and etc) when doing a routine oil & filter change.

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.

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

Your oil cooler will add about 1/2 of a quart, your filter dry will add about a 1/2 quart...given that you can expect about 9 at a minimum to top everything off.

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)

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.

So say if I add the deep sump spacer which adds about 1/2 quart. I put 9 quarts total in, the electric oil gauge shows more than full (above the full mark). How does that make any sense? :confused:

Didn't let it drain long enough, maybe....?

I've never given the dealership (Redline 5W40) or the indy shop (Mobil 5W50 and Joe Gibbs DT40) more than 8 quarts of oil for a filter & oil change, and my cars are always returned right at the top fill bar (1 bar below the over flow bar).

I do my own oil change and I let it drip long enough. Then again I also have a X51 oil pan so it might hold some more oil in there as well compare to the OEM pan.

The manual says you check the oil with the motor hot (that means running for a good 45 minutes), then wait a "few minutes" before checking. To me, a few minutes means 3-5. When I follow this procedure and the dipstick shows full and the dash gauge shows full, the next morning after the oil has drained down into the sump, the dash guage will show one bar above full.

I believe the main variable is how much oil is stuck in the heads particularly the timing chain housing side. The best way to minimize the amount of oil there, is to fully warm the engine & minimize rpms the last few minutes before the engine is shut off to help the scavenge pumps return most of the oil to the sump. I do this & drain the oil ASAP for a least 1/2 hour then add 8 qts. Drive car until at least 180 degrees, park car with engine off for a least an hour. Check oil level at dipstick & dash, then add oil till it is 1/2 qt below full. There is no need to attempt to make oil level perfectly full.

Per the Owner's Manual, an oil & filter change for a 987S (3.2L) requires 7.75 litres of oil.

So:

7.75 litres is 7,750 ml / 946 ml (quart) = 8.19 quarts.

I still wonder how much "old oil" remails in the system, regardless of drain time?

If you're concerned about how much of your old Mobil 1 is mixed in with your new Joe Gibbs oil, I wouldn't worry about it. Based on what was drained out of the system during the oil change, it has to be a very small percentage of what is currently circulating. Furthermore, it will only become more diluted with each subsequent oil change until it is entirely gone.

Not concerned, just curious. I agree, it can't be much.

Your right. I took a drive to work this morning, shut the car off and turn the car key, waited 1 mins for the counter to cycle through and it does read full instead of overfill.