Hot or cold oil change protocol and T-stat or none for auxiliary oil cooler?

[GTP]

I am running a Setrab sandwich plate under my oil filter to flow to a big Setrab cooler. System is working out great.

I got to wondering if the Tstat is even required at all for my combined track & DD car. My logic is as follows.

195F normal CHT while street driving
228F steady state CHT on track, Tstat fully open.
Therefore the Tstat opens also while street driving and flows oil through the cooler even on the street.
All good so far.

However, when it comes to changing my oil I do it with the engine cold. So the Tstat is closed and any old oil remains in the cooler. I typically get 9 quarts out from the 11 quart system. The cooler holds about a quart, leaving a quart in the engine.

I have two options to get the old oil out:

Drive the car until normal 195F operating temperature and then change the oil. OR
Remove the Tstat altogether.

I prefer the second option. Can I remove the Tstat and blank off that hole with a fitting? Or, can I disassemble the Tstat internally and then screw the outer fitting back into place?

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[NightmareMoon]

I’ve got the same story. Setrab cooler an sandwich tstat plate. It only took 8l on the last change and it should take ~10.

 

[GTP]

Here is what Marv at Setrab USA said in his email:

​

There is no need to drain your oil cooler when changing your oil. The volume of oil residing in the oil cooler is minimal. The oil passageway volume is mostly displaced with turbulator devices (devises that gently stir the oil as it passes from one side of cooler to the other). You may view the amount of oil in your specific oil cooler here, Engine_Oil_Coolers.pdf​

​

The small amount of residual oil remaining in the oil cooler after an oil change will be scrubbed by the oil filter during its next pass, then co-mingle with new bulk oil.​

​

If your mounting choice places the connections allowing oil to gravity drain at vehicle rest, you'll remove virtually all old oil. Again, not necessary, but how it will work.​

 

[GTP]

So I can say with confidence that changing oil when the engine is warmed up drains all the oil out.

I use a Ronin drain plug and 5/8" vinyl tube to drain directly into old jugs. You can see 5 quarts in the left jug and 6 in the right jug. My system holds 10 quarts plus another quart with the auxiliary cooler.

The new challenge that I didn't anticipate is how the tube gets softer with the heat and popped off the Ronin drain adapter. So I ended up spilling some oil while I had to rush to unscrew the adapter. I drained the old filter and catch can into the jug, too.

 

[GTP]

I modified the drain tube. Inside spring to prevent kinking (secured by a nail with tip ground flat). Tie wrap near adapter barb to prevent it from popping off.

GTP’s Poor Mans McLaren (w/ pics, tips, & techniques)

 

[kz]

Since I just changed the oil yesterday - my engine somehow holds full 11 quarts without any coolers - do you remove the filter when drain plug is still out ? In my case that causes decent amount of oil to come out of the oil pan the moment i take filter off the threads (when i completely remove it, not when I start turning it and oil starts draining.

 

[GTP]

Yes, I remove the filter while the pan is still open. I haven't noticed if the drain tube suddenly has more oil coming down.

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