Oil Change Question

[RWebb]

I agree -- don't worry about it.

In general, drive the car until the temperature stabilizes and then drive it another 20 minutes. A few short trips won't kill it. It is a chronic sort of thing.

[AlfonsoR]

Oil itself has a very long shelf life, almost forever. If the car has been in a climate controlled or at least protected from the elements in a garage, I would not hesitate to get the engine up to normal temp in order to change the oil.

Will F is right. What you have to worry about is acid and corrosion. If the car were to sit outside in the sun and rain and snow for a couple of years, you could potentially get enough condensation from the change in temperatures to ruin the oil. In that case, I would change the oil cold, then run the engine to normal temp for an hour or so, then change the oil again.

[Amanda]

FWIW, the car has been in a garage here in sunny, mild California. Just bought a Mahle filter and a case of Brad Penn 20W-50 for this weekend.

[trond]

If the oil does not contain water and is reasonably clean (looking) it will be fine sitting. If the car is used for short trips in a cold climate there will be free water from condensation, and water is not good in the oil tank or in the engine

On other cars and bikes I have always replaced oil at 3000 miles intervals, but with the stupid cost of good oil here and the 12 liter capacity it is always tempting to stretch it. Typically a good quality Pelican Forum approved oil is 400-450 dollars for 12 liter, and that is painful.

[HarryD]

Trond:

You should be able to get some good oils locally that may be less expensive. You are looking for high Zn/P numbers and a decent detergent package.

A trip to your local Auto Supply houses and perhaps a chat with some of the local wrenchs may reveal a better deal for you. You can always look the data up on the vendor web site and/or pay for a virgin oil analysis to confirm.

[trond]

After reading all of the posts in the big oil thread (why we hate...), just buying an oil is no longer an option..... And what happens as service intervals for cars increase to the ridiculous numbers and sump volumes are small, maybe a gallon, is that oil price goes up. In a small market as this high markups are given

[Wil Ferch]

The problem, if we are honest with ourselves...is this--->

We say ( and repeat) things like ("change every 3000 miles"), because we've been conditioned and have experience doing this...and all seems fine in the end...no disasters...and the cars we speak of doing this to, last 100,000+ miles. The real problem is that we don't approach this in a scientific way...and we really can't...because it would take a "controlled case study", with at least 2 equal vehicles and running one car to destruction as we experiment with other things like vastly extended oil change intervals. We're not about to do that.

So...that leaves us proclaiming doing "X" as a procedure, and not having any duplicate cars going thru a controlled test with alternate intervals to truly judge.

Then there's this---> we say do "X" ( like change every 3000 miles) and we proclaim victory when a car'e engine goes maybe 100,000 or 200,000 miles without problems. How do we know that this is "good"? What if high-focus on extreme filtration , lengthened oil change intervals, and oil analysis done in-between....results in a "normal" 500,000 mile life engine?. How would we know?

If you follow some of the oil-guys on this board ( and other boards catering to oil issue), I think you will find that they have experience and data that tends to suggest this is true.

[dynafan]

I'm one month into owning my 82 911sc, I've been told by the local guru to use an oil he sells (exclusively) that contains paraffin. Anything else will destroy my air cooled engine. Yes No??

[Por_sha911]

dynafan: welcome to the board.
Logic will tell you that any time someone says "only use the oil I sell" that there is (at best) no impartiality. The nice thing about Pelican is that we have people who are experts on air cooled Porsches (not myself) who have nothing to gain by their recommendations.
You will find that there is a ton of info on this website via the search button. For instance if you look up ultimate oil you will find more info than you ever wanted to know.
In the meantime, we have an unofficial unwritten tradition that newbies post a pic of their car so we can ooh and aah over it.

[HarryD]

Our older cars need higher levels of hi pressure anti wear additives than newer cars. The typical additive is ZDDP which contains the Zinc & phosphrous you need. There are numerous suppliers but Brad-Penn 20W-50, Valvoline VR1, Kendall GT and Swepco are popular. lots of info into the how's and why's in the ultimatte oil thrread.

[Amanda]

OK, more oil change stupidity. I just changed oil with Brad Penn 20w-50, but I still have 3-4 "orphan" quarts lying around, including Castrol Syntec 20w-50 and Mobil1 Extended Performance 15w-50. Would it be OK top off with these other oils?

Also, instead of Brad Penn, I almost got a case off Kendall GT-1, but for some reason, I didn't want to go back to dino oil after going 100% synthetic w/o leaks. Are there any concerns with switching back and forth - synthetic to dino and vice versa?

[HarryD]

Hi Amanda:

IMHO the dino vs synthetic debate is no longer valid. The issues that made it relvant in the early days are no longer there so switch and mix as you see fit.

The larger issue is ensuring that your engine has the correct lubricating oil additive package to preserve it's life for the long run. Given the cost of a Porsche engine rebuild, I would be inclined to use up the other oils in a less critical car by blending a bit with each oil change for those cars.

Does this help?

[RWebb]

I would not top off with those other oils - use them in some modern car you don't care about much, or give them away.

Nothing impresses a gf on her birthday like a shiny new can of oil with a ribbon on it.

[pwd72s]

Originally Posted by twistoffat

Oil change once a year or 3k miles which ever comes earlier

That said, The owner's manual of my '72S called for every 10,000 or once a year, and that was when synthetics were just entering the game. The '72 owner's manual also called for single weight oil.

I would suggest you drive the car more...at least 20 minutes per month. And DO change once a year.

Since you use mobil one, you probably got away with it...this time.

[pwd72s]

Originally Posted by HarryD

Our older cars need higher levels of hi pressure anti wear additives than newer cars. The typical additive is ZDDP which contains the Zinc & phosphrous you need. There are numerous suppliers but Brad-Penn 20W-50, Valvoline VR1, Kendall GT and Swepco are popular. lots of info into the how's and why's in the ultimatte oil thrread.

Harry...I've noticed in V-8 car mags that Comp Cams now offers an oil with ZDDP under it's name. "For flat tappet engines and for break-in." Might be worth some research among the P-car folks.

[Wil Ferch]

I'll be the heretic and ask another tough question. The ZDDP additives are important for high-point-load applications, and we seem to say the cam/rocker-foot interface is such a point in our cars. However, from other sources discussing other topics.... I seem to recall a small factoid like this---> that American V-8 muscle cars, with their high-inertia valvetrain using push-rods and such.... NEED high valve spring pressure to prevent valve float at high RPM's. In contrast, our rather sophisticated SOHC engines have much less valve train inertia....and therefore can get by with much less spring pressure. I can't confirm , but something like 60 pounds pressure vs a hi-po domestic V-8 needing 100-120 lbs. Anyone close to this topic care to confirm?

If so....are "our" engines the ones that NEED the high levels of ZDDP afterall?.

[HarryD]

Originally Posted by pwd72s

Harry...I've noticed in V-8 car mags that Comp Cams now offers an oil with ZDDP under it's name. "For flat tappet engines and for break-in." Might be worth some research among the P-car folks.

Hi Paul:

Long time, no see. Hope you and your lady are doing well.

There are several of these additives on the market now. They do seem to offer some hope to boost a marginal oil. Based on my conversations with Mr Weiner and Mr Navarone you can get to the same place with one of the "speciality oils" like Brad Penn, SWEPCO, VR-1 etc.

In one way we are lucky in that we use 20W-50 oils that are not required to have lower ZDDP (like the lighter oils). Our task is to find vendors that choose to have enough ZDDP to meet the SAE Recmonnedations for flat tappet engines.

Take care!

[HarryD]

Originally Posted by Wil Ferch

I'll be the heretic and ask another tough question. The ZDDP additives are important for high-point-load applications, and we seem to say the cam/rocker-foot interface is such a point in our cars. However, from other sources discussing other topics.... I seem to recall a small factoid like this---> that American V-8 muscle cars, with their high-inertia valvetrain using push-rods and such.... NEED high valve spring pressure to prevent valve float at high RPM's. In contrast, our rather sophisticated SOHC engines have much less valve train inertia....and therefore can get by with much less spring pressure. I can't confirm , but something like 60 pounds pressure vs a hi-po domestic V-8 needing 100-120 lbs. Anyone close to this topic care to confirm?

If so....are "our" engines the ones that NEED the high levels of ZDDP afterall?.

Based on my conversations with Steve Weiner (who has seen more damaged engines than I ever will), part of what started this whole concern was the observation by the engine builders that the cams were showing excessive pitting. This corresponded to when when the oil makers started lowering the ZDDP Content of their oils to meet EPA demands. This pitting has been observed on Porsche cams, so, in my mind, we need to be concerned.

[LeakProof]

Yea, tell me about it!
Leakproof.

[nesslar]

Yep. I drive enough that I wouldn't even consider 12 months/3000 miles, and usually get things up to temp.....the companies that make the stuff are overpaid already, why overkill if not necessary? My car does not sit for months at a time, obviously, not even weeks....barely DAYS!! If I had horrid conditions to deal with for extended periods, I'd just drive it in whatever weather anyway....or sell it!