I have thought about this a few times and forget to ask if this matters, . do we just not worry about that extra quart or so that is in the cooler and cooler lines, OR option 2 drain it or 3. run it after changing it, long enought to open the thermostat that allows for the oil to circulate thru the cooler and run it for a while and then change it again?
seems we are only getting about 3/4 of the oil out and changed if i leave it in there- my motor is a stock 2.0 and the cooler was installed at Tangerine racing, it is small one that comes off an adaptor plate on the oil filter location.

thanks for the input.

Phil

Live with it, just change the oil at least once a year.
Also it's less oil than you think.

Doc,

You're over thinking it.

Alternatives:

1) Don't worry about the oil in the lines. If you're changing it regularly at 3000 mile intervals, that oil isn't that dirty.

2) Change oil on a slope and/or crack fittings to drain all oil. Now you have a big slug of air in the lines and the cooler that eventually needs to be backfilled. That will result in a drop in oil pressure. Either delay of presure when you start the engine 1st time or when your thermostat opens. One way or another the pressure has to dip when that void is filled.

Personally, I'd go #1.

On a related note - how do you properly fill a system with a dry cooler? The thermostat will be closed on a front mounted cooler so how do you get oil into that part of the system so the level doesn’t drop when the thermostat actually opens?

I put some oil in the cooler before attaching the lines. My lines enter at the top so it was easy.

I don’t think anyone really worries about getting the old oil out of coolers on all the modem cars. Like superhawk said, it’s very little volume.

@Tdskip i think this is why when i go to Valvoline for example for my truck, they run it for a while then recheck and top off? then turn it off and recheck level and show you your level too - so that they can make sure a vehicle with an oil cooler has that oil circulating and levels are good. i dont tknow but seems plausible

@mepstein
@superhawk996
@Mark Henry

thanks for the responses, i figured i was overthinking it, and will just change it like i have been .

Yup, that's pretty much it. Lots of vehicles now have oil to water coolers. You can be sure you're not getting every last ounce drained out of those coolers when you get an oil change.

As previously stated by Mark, you can pre-fill the cooler. I've done it on race cars. Sometimes makes a mess as you go to reconnect the fill line. Oh well. That's what brake cleaner is for right?

Yup!!
I probably will do that 1x a year , empty the cooler and refill it with new clean oil, but it hasnt been emptied out since it was installed so i might do that soon. not today, i am heading down to florida this afternoon/evening to spend some time with my daughter and son-in-law-to -be-soon and go to the Jax Porsche Classics grand opening!!!! hope to see some other 'Teeners there tomorrow.
first road trip since the redo on the transmission and other stuff, so hoping to have a good drive, so far i am loving how its running, man i love this new exhaust!!!! thanks Ben @mb911

Hope your trip is fantastic.