Oil Change w/ Front Oil Cooler proceedure?

wowzer911 · 11-05-2005, 06:15 AM

Dumb Question?
What's the proceedure for performing an oil change with car equipped with a front oil cooler?
I've read some where that there is some danger of hot oil entering a cold (empty) oil cooler?
Do you even drain the oil cooler & lines?
Need some help w/ this.

Geronimo '74 · 11-05-2005, 06:20 AM

Procedure:

1. Drain old oil

2. Put in new oil

3. dispose of old oil in environmental friendly manner

Sorry, i actually don't know, hope somebody else does

livi · 11-05-2005, 06:44 AM

Never heard of any problem like that.

In what circumstances would hot oil enter cold cooler ? You empty out hot oil, leaving the whole system with a bit of heat. You pour in rather cold oil, which you then gradually heat up driving.

wowzer911 · 11-05-2005, 07:05 AM

I had read that (here) somewhere. So do I drive around till my cooler t-stat opens up, then add more oil?

wowzer911 · 11-05-2005, 07:14 AM

BTW, that's when hot oil might enter cold front cooler.

livi · 11-05-2005, 07:22 AM

There will be some oil left in the cooler system after drainage, that will keep is warm if you drive the car hot before draining. The changing procedure is quick - it will not have time to cool down completely.

If it was a problem it would be same thing when starting in the morning. When engine hot, opens up for front cooler.

Or am I missing something in your post on account of my bad English ?

wowzer911 · 11-05-2005, 07:30 AM

No, i'm just asking the question.
So, I can drain all oil from system, incl. front cooler. Refill, bring up to temperature, then top off with additional oil as needed, without any problems? GREAT!

livi · 11-05-2005, 07:33 AM

Being rather new to this, I would advice you to wait for the more competent answers though...

cyprusx · 11-05-2005, 07:41 AM

There is no need to drain the cooler and lines... Just drain the engine and the tank, add 9 quarts. Run till hot and while running on level surface, check oil level. If it is not in between the two marks on the dip stick, add a little until achieved.

wowzer911 · 11-05-2005, 08:05 AM

I have not drained the front cooler in the past, but was never really comfortable with that.
The main reason I'm asking is that I'm replacing my old rubber lines with new braided stainless steel ones, and am wondering if there are any dangers of the hot oil entering an empty front cooler. Or is there a better way to go about it, such as prefilling the cooler with oil?

Wil Ferch · 11-05-2005, 08:14 AM

Porsche systems that use a front cooler have a total capacity of about 13 qts ( +/- .. depending upon year).

Whether you like it or not.... the "change-out" capacity is about 10 qts max...sometimes 9. About 3 qts always stays behind !

Just drain/refill as posted here. Proper oil level is read when ALL THREE ( car on on level ground, temp up to 190 degF or white line around 8 0'clock, idle speed of about 800-900 rpm)....is achieved. There might be a need to fill more once the right-rear oil thermostat opens and begins flow to the front. Don't overfill. Fill to mid point of dipstick. This SHOULD be equal to a mid gauge reading when ALL THREE factors are in-place. Level will show red zone on the gauge once you're driving. No worries. It should go mid range at idle again.

Wil

wowzer911 · 11-05-2005, 08:19 AM

So when replacing my front oil cooler lines (latest project) should I prefill my front cooler with oil? Or is it OK to leave it empty, and let it fill when the thermostat opens up?

Wil Ferch · 11-05-2005, 08:26 AM

It's ok to leave empty...just let the system got hot so the flow to the front is established....and add more as necessary. The system to the front cooler works on the scavange ( not pressure) side of the system, and usually flows a mix of oil/air anyway.

Wil

Chuck Moreland · 11-05-2005, 08:33 AM

No worries about hot oil entering the cooler. This won't do any damage.

Like Wil says, normally a couple quarts are left in the oil lines and cooler. If you have the Elephant Racing finned lines you can remove this oil with the purge valve.

wowzer911 · 11-05-2005, 08:34 AM

Thanks Wil

Bill Verburg · Bill Verburg's Garage

I have a drain on the front cooler but never bother w/ it. Change the oil regularly to remove the worst of the condensates and refresh the additive package, a few qts of old oil won't be an isssue.

randywebb · 11-05-2005, 02:30 PM

You can calculate this...

Say you have 10 qts. toatl w/1 qt of old oil and 9 qts. of fresh oil -- now your oil is 90% fresh. To compare with an more or less extended drain interval with "all" fresh oil, just assume a numeric value for how old the old oil is... you can use different numbers for different parameters, such as TBN, suspendided metals, quark flux or whatever you want...

Botton line - just change it periodically and don't worry -- you'll have plenty of other things to worry about with an old car anyway -- no need to make up more...