Oil type questions

[Troubleshooter]

Hi, I'm a newbe with an 86, 911.

I know these are elementary questions but need some hand holding here.
The previous owner not sure what type oil is in the car. I think he had synthetic since
one of his service slips had Cas Syn 5W30. Is this OK?
The owners manual says I can use Synthetic oil.
Fact or myth... Synthetic oil being so slick/thin can cause leaks in seals etc.
What type filter should I use that's good but cheaper than Porsche Dealership?
Is Trans. oil SAE 90 Hypoid GL 5 for Carera's the best?

Troubleshooter

[Bill Verburg]

Originally Posted by Troubleshooter

Hi, I'm a newbe with an 86, 911.

I know these are elementary questions but need some hand holding here.
The previous owner not sure what type oil is in the car. I think he had synthetic since
one of his service slips had Cas Syn 5W30. Is this OK?
The owners manual says I can use Synthetic oil.
Fact or myth... Synthetic oil being so slick/thin can cause leaks in seals etc.
What type filter should I use that's good but cheaper than Porsche Dealership?
Is Trans. oil SAE 90 Hypoid GL 5 for Carera's the best?

Troubleshooter

Cas Syn 5W30. Is this OK?

not a good choice for our older cars. That is a modern fuel economy oil that is light on ZDDP to prolong the life of modern emissions systems

when your car was new the recommended oil was a 20w-50, category SF oil. These a oils predate the current GF standards which started in 1990 w/ GF1 and are now transitioning to GF5.

to get a an oil somwhat comparable to the SF oil originally used in 1986 you will want
Mobil 1 15w-50
Castrol Syntec 20w-50 classic(now transitioning to 5w-50 classic)
Brad Penn 20w-50
Joe Gibbs 20w-50
in general the 50weight oils are not subject to the reduced ZDDP that the lighter weight oils are. What ever you do do not use an oil w/ the starburst symbol
bad


good in the heavier xxw-50 weight oils

Fact or myth... Synthetic oil being so slick/thin can cause leaks in seals etc

myth

oil filter - I only use Mahle in mine

trans fluid I like Swepco 201, others like Kendal

[Buckterrier]

What Bill says, he is one of our resident gearheads.
Are Porsche guys aloud to be called gearheads?

[Flat Six]

Welcome! You'll find lots of help and advice here. You'll also get some good-natured ribbing, especially about sharing photos of your new p-car (obsession).

Seriously, though, a few good pictures not only helps introduce you to the rest of the Pelican community, you'll be stunned by the wealth of knowledge that members here are able to share just by examining your photos -- some really sharp-eyed and incredibly knowledgable people here.

Also, you probably want to update/edit your signature or 'About Me' section to give some idea of where you're located. Often plenty of local Pelicans willing to help, loan expertise, provide local recommendations, etc. And sometimes, advice can be region-dependent (weather, laws, product availablity, local sources, etc.).

Regarding your oil and transaxle lube, Bill offers (as always) sage advice. Couple of notes, though. Others have had similar success/satisfaction w/Valvoline VR1 Racing 20w50 and Kendall GT-1 20w50; may or may not be available in your area. If you have several hours free and want to read more about why, try this:

Ultimate Motor Oil Thread or Why we hate CJ4/SM oils

Bill prefers Swepco 201 as do many here; others -- as he notes -- prefer Kendall NS-MP (both available from our host). Both are, I think, 80w90. Some here use Swepco 212 instead of 201 since it's 85w140 (due to very hot climate and/or extreme duty use). But -- just to be clear -- even though it appears in the photo Bill posted, don't use Mobil Delvac or most other synthetics in your '86 915 transmmission.

Best,

Dale

[DRACO A5OG]

Stick with 20W50 Conventional with plenty of Zinc, if pre-existing leaks.

Partial Synthetic 20W50 if Leak Free

Stay away from 100% Synthetic. FACT

Trans/Gear Lube: 80W90. If you have LSD you need the additive or she will sound like a tank.

I purposely did not post a BRAND because too much has been said already about it. It is your car your choice. If Frequent Oil Changes, and if she is healthy you should be trouble free. Enjoy and Welcome to the BOARD!

Pics?