steerpike

I am looking for someone who knows if flushing the old oil when changing engine oil is a good idea in 1997 47000 mile 993 cab and what is rthe best flushing agent?

Thanks in advance.

ca993twin

I don't know of anyone that "flushes" the old oil in a 993. The trick is to ensure that the old oil is REALLY hot when you drain it. If there is something out of the ordinary going on that makes you think you need to flush, instead do a second oil change after a thousand miles.

certz

I would contact Charles Navarro at LN Engineering:

info@LNengineering.com

MarkD

it's not necessary at all

+1 on what Steve said above

ca993twin

Crikey. And I just make this stuff up. Toss enough stuff over the wall, and once in a while you hit the target. Or, as the old slogan from HWFMR, "If you spin often enough, once in a while you'll hit the apex".

MarkD

LOL

you are funny...

you know much more than you let on
So modest

Steve Weiner-Rennsport Systems

I agree with them,.....

Pete Lech

If you are upgrading from dino oil, it would be a good idea to do another change in 1000 miles or so, as the synthetic could free up a lot of accumulated crud.

Even if the system is really hot, there will still be 3+ liters of oil in the system, including the front cooler and lines that does not get changed. You would not get the flushing chemical out of the the system with a regular oil change.

FYI, after running the car, my mechanic lets the car sit, overnight if possible, and then drains the oil.Since he has 30+ years Porsche experience, including building 911 racing engines, I defer to his knowledge. I would think that that time would let all the oil settle to the bottom of the engine, and be a lot easier on the changer.

IXLR8

You have a bit more mileage than I have. I don't have any prior history on the number of oil changes and how often, but the last time I had a valve cover off, the engine could have passed for new.

Do regular oil changes using quality oil and the internals stay clean.

NC TRACKRAT

"FYI, after running the car, my mechanic lets the car sit, overnight if possible, and then drains the oil.Since he has 30+ years Porsche experience, including building 911 racing engines, I defer to his knowledge. I would think that that time would let all the oil settle to the bottom of the engine, and be a lot easier on the changer."
It might be easier but, unless the oil is hot enough to open the thermostat, he's leaving a lot of oil in the system.
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Ed Hughes

I'm not interested in making anything easier on the changer, in my case, me. Drain it while it's hot. That flows the oil out quite nicely, t-stat is open, etc.

steerpike

Seems, from what I hear, and taken "seriously" that it would be wise to leave well alone and not do the oil flush at all?

No one has mentioned a good flushing agent for use.

Mark in Baltimore

No one has mentioned a good flushing agent to use since no one has recommended flushing the engine.

Paul M

Two words: Dry Sump.

Quadcammer

T-stat open or not, you are going to have oil that sits in the front oil cooler unless you have the front of the car about 4 feet above the rear.

With 5k mile oil changes, the oil in the front cooler is academic.