Re-using engine oil

[911pcars]

I don't see a problem re-installing the same oil that came out of your oil tank. If the drain and storage process is as clean or cleaner than the inside of your current tank, should be fine.

It's not as though one were transfusing human plasma while risking the development of acute immune hemolytic reaction. Relax.

However, if there's little trust in a funnel and a collection of sanitized storage containers, one can always gift the FLAPS half a C-note (or more) for a case of virgin 20-50.

Ditto for gear lube.

Sherwood

[Lapkritis]

Originally Posted by Smoove1010

It's very tempting to re-use all that oil, but I can't shake the image of those tiny orifices in the piston squirters. I'd go to some pretty extreme lengths to insure that the oil I was putting back was perfectly clean.

Agreed. The lengths I would go to are having the oil refined/recycled and repackaged. In other words, go buy fresh oil and recycle the old.

[C4UKPOR]

Coffee filter sounds a good bet.
When I said leaking cam cover I meant timing chain covers.
Does the oil need to be drained to remove these?

[911pcars]

Originally Posted by C4UKPOR

Coffee filter sounds a good bet.
When I said leaking cam cover I meant timing chain covers.
Does the oil need to be drained to remove these?

Not the complete sump volume. To know exactly, position a large drain pan under one chain box, then remove it's cover. The rear end of the car is probably higher than the front, thus only some of the oil will drain out. I suspect about a quart will drip out.

Sherwood

[C4UKPOR]

Thanks Sherwood,
I'll try removing one side without draining oil. Probably jack the back end up and put it on axle stands first so the oil will drain away from the chain boxes.

[fred cook]

I have done this, but before putting the oil back in the engine, I run it thru a very fine screen filter. When I say very fine, it is border line micro. It is built into a funnel w/cutoff valve and hose that I bought from an auto parts store. I also needed to drain the new oil from my engine to do some bottom work and did not want to lose 9-10 qts of new 20-50 oil. So, I ran it thru the filter, cleaning the filter after each 5 qts. All that I found in the oil were some "crumbs" of the block sealer that had "squished" out when the block was assembled. Ran a magnet over it but nothing was attracted to the magnet and nothing looked anything like aluminum. After cleaning the screen, I used the same funnel/filter combo to put the oil back in the engine. That way it had been double filtered.

[bodmin]

Just a thought, but I'm sure it would be quite easy to make a small jig to filter the oil through a car oil filter before returning it to the oil tank. A pressure braker bleeder could be used to store and pump the oil under pressure with an 'in line' car filter downstream of the pump.

That way the oil is pre-filtered to the same standard as the oil circulating system before it enters the oil tank.

[Tippy]

Cam covers don't require draining oil IMO. Very little stays in the housings.

[88911coupe]

I used a paint filter but it took a LONG time IIRC. I see no reason to throw out good oil before its led a useful life. As some have pointed out, the better option may be to avoid draining it in the first place.

[awhnry]

We used to reuse our racing oil after two weekends in the tow vehicle. Filter it and use it in something less sensitive if you are concerned about cleanliness; otherwise just pour it back into the oil tank of the 911.

[911pcars]

Maybe I'm missing the need for this OCD behavior. Other than debris picked up at your exit point or from compromised storage containers, where is this contamination coming from that one has to replicate or improve upon the filtering system provided by the engine's lube system before pouring it back in the engine?

But if you must, here's one method mentioned in several sites:
http://www.endtimesreport.com/cleaning_engine_oil.html

S

[Smoove1010]

Originally Posted by 911pcars

Maybe I'm missing the need for this OCD behavior. Other than debris picked up at your exit point or from compromised storage containers, where is this contamination coming from that one has to replicate or improve upon the filtering system provided by the engine's lube system before pouring it back in the engine?

Unless the OP's undercarriage is spotlessly clean (and I know many Pelicans have undersides that fit this description) my concern would be any dirt that falls from around the oil-tank, tins, fender-wells, etc. My car isn't terribly dirty underneath, but it does get driven, and some dirt/dust/dead-bugs fall into the drain pail just about every time I change the oil.

There are some good ideas here to avoid wasting the drained oil, but the "don't drain" solutions seem to be the wisest.

If I had to do it, I'd be tempted to carefully pinch the S-hose, then drain the engine case to avoid the tank draining itself down into the case and out the bottom. I'd replace whatever came out of the case with fresh oil. I'm a little too close to a fresh top-end rebuild to want to risk saving a few quarts of oil that badly. That's just my opinion though.

GK

[911pcars]

Another reason to use a Fumoto ball drain valve (Tank only. No worries about frozen drain plugs). Source the version with a hose fitting as shown. With the desired length of hose attached, you can extract as many ounces, pints or quarts with minimal odds of introducing rat droppings, industrial fallout, etc. into a narrow-neck oil receptacle.

[Lapkritis]

This is one of those times that the downside far outweighs the upside. Less than $35 for 3 gallons of DELO at Walmart. I inherited some Great Depression era recycle and re-use habits but these aren't lawn mower engines that take abuse and cost little to revive. Absolutely would not recommend re-using oil in these. Then first time you scrub a bearing from a missed particle is when the $35 for fresh oil will seem cheap. What's the downside of new oil? You're out $35 but you gain piece of mind and a cleaner engine internal. Seems cheap security to me.

[Nick Triesch]

The oil is only a week old! It has thousands of miles left on it. If you do a clean job saving it then what is the problem? After it is reinstalled, it will still be in better shape than the oil in most of our cars!

[manbridge 74]

Just an FYI but I'd wager this is SOP in almost every auto service shop in the world.

Go ahead and include coolant, trans fluid etc......

[Lapkritis]

I never have and never will reuse a fluid drained. It is stupid to take any risk. I don't even take that risk with the old Volkswagens I've owned. I can't believe a Porsche owner would be so cheap as to attempt it... unless they have no cash left after paying insurance premiums and engine rebuilds at $12g a pop. I would rather eat ramen for a month first!

[Schmierung]

We have two threads here:

A) Poster is removing timing chian covers and has concerns about dumped oil. Tippy and others answered that. Raise the rear to high heaven and catch the half pint you may loose if any. Change your tensioner and be done with it.

B) Is it advisable to drain low milage oil and possibly re-use. The answer is yes, provided you can maintain cleanliness. Research the topic on engineering forums. This is an old and ongoing topic for Spaceflight concerning water, refrigeration, lubrication and other systems that we here typically just replenish and throw away.. With proper cleanliness you may re-use lube oil.

[Ronnie's.930]

This "re use drained oil" subject reminds me of the "change oil at 3K miles debate". For some, it seems to offend their sensibilities to go more than 3K on oil, but I find 3K oil change intervals to be grossly wasteful to the point of arrogance.

[Smoove1010]

Originally Posted by Ronnie's.930

This "re use drained oil" subject reminds me of the "change oil at 3K miles debate". For some, it seems to offend their sensibilities to go more than 3K on oil, but I find 3K oil change intervals to be grossly wasteful to the point of arrogance.

Ditto that. For me this question is more about whether you can keep the oil clean enough to put back in. I love that Fumoto drain - seems like an ideal way to make for a clean dump - it would allow you to drain directly into jugs for drop-off, or for re-use. Nice!