Suitable oil for Air-Cooled Porsche(Especially 964,993)

[595_PP2]

I have used semi-synthetic oil(15W-50) and PAO-based full-synthetic oil(10W-40) so far.

Air-cooled engines are said to be oil-cooled engines, and selection of engine oil is very difficult.

PAO-based full-synthetic oil was a very good engine feeling, but unfortunately oil leak occurred.

Now I am using group3-based full-synthetic oil(10W-50), but at present no oil leak does not occur and engine feeling is smooth.

PAO-based full-synthetic oil kept a good feeling until replacement, I wanted to use it even if I could not get any oil leaks ,,,,,,

What kind of thing do you think is suitable oil for Air-Cooled Porsche?

 

[Onetor]

A group 5 ester based oil. Redline, Renewable Lubricants, or Ravenol. Just my humble opinion. I'm no expert, like some of the others.

 

[Onetor]

I see that you are in Japan. Eneos Sustina?

 

[camrydriver111]

The consensus is that oil performance is important.

Whether it uses PAO or Group 3 is not important.

 

[1JZ_E46]

Do you have Mobil 1 15W-50 in Japan? That would be a good fit.

 

[RooflessVW]

Originally Posted by 1JZ_E46
Do you have Mobil 1 15W-50 in Japan? That would be a good fit.

I was going to post the same. M1 15W-50 or M1 FS X2 5W-50 (which is Porsche A40 approved) would be a great fit for your engine.

Redline 5W-40 would do well, as would the Ravenol Racing 5W-40.

Of course Rotella, Delo, or Delvac 15W-40 on a reasonable interval would be perfectly fine.

 

[595_PP2]

Thank you for your reply.

I live in Japan.

My mechanic specializing in air-cooled Porsche says that Group 5 base oils and M1 oils tend to cause oil leakage.

So, I am using personal imports of HPR10 of Penrite in Australia now.

This oil is a group 3 base oil, but I feel that initial performance is high, because of the good performance of the oil.

 

[BMWTurboDzl]

Originally Posted by 1991AirCooled
Thank you for your reply.

I live in Japan.

My mechanic specializing in air-cooled Porsche says that Group 5 base oils and M1 oils tend to cause oil leakage.

So, I am using personal imports of HPR10 of Penrite in Australia now.

This oil is a group 3 base oil, but I feel that initial performance is high, because of the good performance of the oil.



Wouldn't replacing the older gaskets/seals stop the leaks?

 

[RooflessVW]

Originally Posted by BMWTurboDzl
Wouldn't replacing the older gaskets/seals stop the leaks?

Have you priced an M64-05 rebuild lately?

 

[Oildudeny]

something else has to be going on, like previously mentioned such as worn seals or gaskets not being as pliable.

anyway I would try running a "10w60" once you have checked over the engine.

 

[RooflessVW]

Indeed, Porsche offers their own "Classic" 10W-60 oil for the 993 and below.

 

[BMWTurboDzl]

Originally Posted by rooflessVW
Originally Posted by BMWTurboDzl
Wouldn't replacing the older gaskets/seals stop the leaks?

Have you priced an M64-05 rebuild lately?



I thought all Porsche owners had their own money tree !

 

[RooflessVW]

Originally Posted by BMWTurboDzl

I thought all Porsche owners had their own money tree !

 

[maxdustington]

Wow Porsche took air cooled engines much further than I had thought.

 

[1JZ_E46]

Penrite is good oil. In addition to my Mobil 1 15W-50 recommendation, you could always try 10W-60 (Castrol, Motul, Liqui-Moly) which is used in BMW's older M cars.

 

[GermanAutohaus]

I have a 964 as well as running a shop that services air-cooled 911s. I currently run Motul 300V Power 5W40 in mine, but used to use Valvoline VR1 20W50 and recommend that for customers 911s. Mine is a pre-June '91 build, so it has the infamous head gasket weeping since the o-ring update was never applied. The amount of oil leaking with the 300V is almost the exact same as when running the Valvoline VR1 20W50.

I've seen the Porsche Classic 10W60 and actually started to sell it, until I sent off a virgin sample for oil analysis. The add pack seemed a bit 'blah' for the price. That, and stepping up to a 60 weight would even further increase the time it take to get the oil up to temperature (which takes a long time anyway). Even though zinc isn't as much of an issue with these air-cooled 911s as people try to stress (only needed for high spring pressure/lift), the Classic 10W60 only hitting 1,007ppm was a bit of a let-down.

Climate-wise, what's the lowest temperature that you drive the vehicle?

 

[George Bynum]

Originally Posted by GermanAutohaus
That, and stepping up to a 60 weight would even further increase the time it take to get the oil up to temperature (which takes a long time anyway).


This confuses me; higher viscosity, higher pumping losses, more energy into the oil, more rapid temperature rise. At least that is the situation with hydraulics. Can you explain why motor oil behaves the opposite way?

 

[595_PP2]

My car is running about 100,000 kilometers, but I have never done a rebuild yet.

However, I changed the cover gasket several times.

There is a possibility that the oil may leak from the gap of the cylinder, and it may not be able to completely stop the oil leak unless it rebuilds.

I feel that Penrite is a good oil.

This summer in Japan is getting hotter and hot and humid.

So, I think that 10W-60 is suitable for the summer, but in winter it may be below freezing, so its viscosity may be too thick.

 

[GermanAutohaus]

Originally Posted by George Bynum
This confuses me; higher viscosity, higher pumping losses, more energy into the oil, more rapid temperature rise. At least that is the situation with hydraulics. Can you explain why motor oil behaves the opposite way?


More oil heat is generated by contact with combustion metals than it is by being compressed to 40-60psi. Best guess would be in hydraulic systems the only source of heat is the pump and compression forces, while in engines your major source of heat is thousands of fuel explosions per minute.

It's more about the colder, more viscous oil limiting the circulation speed of oil in the system, therefore impacting the heat transfer rate. The general rule of thumb is to run the minimum oil weight that will maintain adequate oil pressure. Anything greater will negatively impact heat transfer due to additional pumping losses.

How fast can you move oil through the system to remove heat? Don't move enough volume and you're not dumping enough heat.

 

[BrocLuno]

Most oil heat is generated within the bearings as shear induce liquid friction. Sump oil heat comes from the cooling of hot metal parts (heat transfer function). Air cooled Porsche's that are not being track'd should use an xW-50 from the Porsche A40 list. Lots to choose from there.

Synthetics leaking may be function of old hard gaskets and seals and the number of heat cycles they have experienced. If your mechanic says he thinks this one will be a leaker, stay away. It prolly does not freeze where you are (?), so the xW side does not mean much. The op temp grade does mean something. You have some accumulated wear and there are hot spots in air cooled engines, so 40~50 grade is good.

Penrite makes very good oils. But so do some of the Japanese refiners. You might see what is available on the A40 list at motorcycle shops ...