MOBIL1 0W40 or 15W50 for Porsche 993?

[Doug Hillary]

Hi,
for those non Porsche people reading this Thread the following comments may assist in understanding the various Posts

The Thread commenced regarding the 993 (911) MY93 to MY98
This series 911 is judged by many to be the very best of them all (air-cooled) and they had vastly different engines from earlier air-cooled Porsches. As examples they had hydraulic valve actuation and (over time) Variocam/Varioram technologies

The correct viscosity lubricant is important in these engines and the TISBs apply of course

For earlier air-cooled Porsche engines back to MY84 the factory uses the same TISB lubricant recommendations

Prior to MY84 Porsche used a "mixed fleet" HDEO as the factory fill (Shell's Rotella and/or Rimula). This type of lubricant was used over many years from the first 911s in 1963 and it was a SAE30 monograde with SAE20 & SAE40 options according to operating conditions (ambient and etc)

Today many owners of these dry-sump engines find that a modern "mixed fleet" 15w-40 HDEO performs best of all and that they provide better cooling than the mineral based SAE50 viscosities do

As stated earlier the Porsche factory uses these 15w-40 mineral lubricants in their own early air-cooled engines

 

[Kitto]

Doug Hillary, hope it's not off topic. Would you mind to share some insights about difference between M1 5W50 and M1 15W50 because we have no M1 5W50 in the state. Thanks a lot!

 

[sprintman]

Doug can you check pm's as I sent you a few. Maybe your inbox is full? Tks..s

 

[Doug Hillary]

Hi,
sprinrtman - No messages, not full please fire away

Kitto - It is all to do with the formulation of course. Tracking the viscosities of the two lubricants from a base of say 0C shows quite a wide variance until near the normal "core" Porsche lubricant operating temperature of around 90-95C

Porsche and Mobil would no doubt have "liked" a suitable result but M1 5w-50 is still the only WW SAE50 Approved product except essentially in NA - as it has been since 1999

I think M1 15w-50 is a great product too, robust and very viable in many engine families

 

[Johnny]

Originally Posted By: Doug Hillary
Hi,
for those non Porsche people reading this Thread the following comments may assist in understanding the various Posts

The Thread commenced regarding the 993 (911) MY93 to MY98
This series 911 is judged by many to be the very best of them all (air-cooled) and they had vastly different engines from earlier air-cooled Porsches. As examples they had hydraulic valve actuation and (over time) Variocam/Varioram technologies

The correct viscosity lubricant is important in these engines and the TISBs apply of course

For earlier air-cooled Porsche engines back to MY84 the factory uses the same TISB lubricant recommendations

Prior to MY84 Porsche used a "mixed fleet" HDEO as the factory fill (Shell's Rotella and/or Rimula). This type of lubricant was used over many years from the first 911s in 1963 and it was a SAE30 monograde with SAE20 & SAE40 options according to operating conditions (ambient and etc)

Today many owners of these dry-sump engines find that a modern "mixed fleet" 15w-40 HDEO performs best of all and that they provide better cooling than the mineral based SAE50 viscosities do

As stated earlier the Porsche factory uses these 15w-40 mineral lubricants in their own early air-cooled engines


Doug,

Thanks for the history lesson on Porsche.

 

[tilley]

I think Mystic would be hard to find in my area. I have a couple of synthetic-blend options available though, that are easy to get here: Total 7000 Quartz 15W50 and Motul 6100 Synergie 15W50. I was considering one of these, but I think if I at least satisfy 2 out of 3 aspects of Porsche's latest Approved Oil TSB (full synthetic; brand; but stray a little on viscosity), I'd be closer to their target oil and feel better about what I'm pouring into my engine.

 

[tilley]

Originally Posted By: tilley
I think Mystic would be hard to find in my area. I have a couple of synthetic-blend options available though, that are easy to get here: Total 7000 Quartz 15W50 and Motul 6100 Synergie 15W50. I was considering one of these, but I think if I at least satisfy 2 out of 3 aspects of Porsche's latest Approved Oil TSB (full synthetic; brand; but stray a little on viscosity), I'd be closer to their target oil and feel better about what I'm pouring into my engine.


Actually, I'd be satisfying more like 2.5 out of 3 aspects of Porsche's latest Approved Oil TSB: The M1 15W50 would work like the Approved M1 5W50 at normal operating temperatures.

Like Doug H said previously, a big part of choosing the right oil is what makes you feel good. I believe the M1 15W50 is that oil, except....Doug, you say that M1 15W50 is a great product. Are you referring to the new SM type (which seems to not have any ACEA approvals as yet [ref Mobil 1 Product Guide 18Dec07]), or the older SL type (which by all accounts was very well respected for air/oil cooled engines).

 

[Doug Hillary]

Hi,
tilley - Both new versions of M1 15w-50! Do not use a ILSAC GF-4 rated version of any lubricant in a Porsche engine (V6 Cayenne (VW) excepted)

 

[gtx510]

http://www.lnengineering.com/oil.html air-cooled Porsche oil info

http://sterkel.org/systems-engineering-a...Classic_Car.pdf
http://sterkel.org/systems-engineering-associates.com/papers/avocations/How_Much_Additive_To_Use.pdf

http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf
imo, 5W40 TDT (Delvac) or 15W50


Wouldn't using a thinner oil make the engine burn more oil?
Porsche dealers probably use 0W40 b/c that's what they stock for the newer cars.

 

[Doug Hillary]

Hi,
gtx510 - Oil consumption depends on many factors. Previous Posts in this thread contain a lot of very relevant data

As for Porsche engines it is "acceptable" to have up to 1.5 litres/1000kms oil usage

Unfortunately some of the Inengineering data may be inaccurate and some of the assumptions drawn by the Author incorrect

In early aircooled engines a "mixed fleet" 15w-40 HDEO is a great choice - these engines are dry-sumped and have special needs regarding oil foaming tendencies and the like

In Australia most official Porsche Dealers use such an HDEO when servicing the older
This Thread is about the 993 (911) series engines. These of course are post MY84 as noted above

 

[bmwtechguy]

I want to mention one more high quality oil for you Porsche guys to consider. The approved Mobil 1 5W-50 may not always be available as noted, especially here in the states. Schaeffers makes both an excellent 5W-40 and a 5W-50 full synthetic oil, the latter a streetable "racing oil". The 5W-50 smallest container is 5 gallons, but in an air-cooled Porsche, that should not be a problem since they hold so much oil. The price is comparable to the Mobil 1 15W-50, or less, and the Schaeffers site sponsor here would be glad to set you up. Mark is great to deal with, BTW.

You can read more about it here: http://schaefferoil.com/supreme_9000_racing_oil.html

Data sheets:
http://www.schaefferoil.com/datapdf/9001.pdf

 

[sprintman]

I wish we had Schaeffers here..s

 

[mjfx]

I know this is OT. But would it be BAD to mix M1 0W-40 with a qt of 15W-50? I thought it would help a little making the oil a lil thicker. Any negative consequences?

 

[gtx510]

Originally Posted By: Doug Hillary
Hi,
gtx510 - Oil consumption depends on many factors. Previous Posts in this thread contain a lot of very relevant data

As for Porsche engines it is "acceptable" to have up to 1.5 litres/1000kms oil usage

Unfortunately some of the Inengineering data may be inaccurate and some of the assumptions drawn by the Author incorrect

In early aircooled engines a "mixed fleet" 15w-40 HDEO is a great choice - these engines are dry-sumped and have special needs regarding oil foaming tendencies and the like

In Australia most official Porsche Dealers use such an HDEO when servicing the older
This Thread is about the 993 (911) series engines. These of course are post MY84 as noted above

I missed your previous post... I didn't know that the early and late air-cooled engines were different.

What's inaccurate or incorrect about the LN Engineering site? Porsche or oil info? or both?

How's a mixed fleet HDEO different from a regular HDEO?
I'm not familiar with that term.

 

[bmwtechguy]

Mixed fleet HDEO just means that it carries an SL or SM rating for the gassers as well as the current CI4+ or CJ diesel rating. Most diesel oils do have ratings for diesel and gas engines, making them a mixed fleet oil.

 

[Doug Hillary]

Hi,
gtx510 - The answers given below follow your question sequence

1 - Serious and progressive changes were made to the air cooled engines. The lubricant MY "barrier" was established by Porsche via Technical Service Information Bulletins. It is clear that from MY84 onwards Porsche deemed it neccessary to have lubricants with a 0W or 5W cold start rating. An example of the changes are in the valve actuation mechanisms for instance

2 - Sorry but I will not be drawn into an open discussion on this issue - it has been very well covered on Rennlist. Contact me via PM if you wish. I will reply within the next few days

3 - Diesel engine HDEO's are not suitable for use in a petol engine. Mixed fleet HDEOs meet both diesel and petrol engine lubricant specifications. Porsche used such lubricants from their very first cars sold to the public - these were Shell's Rotella HD SAE30 and the like

 

[glenncof]

Update on my Oct. post. Now on my second OCI using 10W40 QS Synth.

I don't expect the oil consumption to go up from what I was getting with 20W50 and the engine appears to like the lower weight in Northern California winter whether. I'm heading into summer but don't expect any change.

Also I'm now at about 20K miles using ~800PPM ZDDP formula's. I have not pulled the valve covers to look at the cams. Mine are stock with no racing.

Right now I believe Porsche was right moving to _W40.

I plan to try the 5W40 but now have a year+ of Penzoil Platinum that I'll blend to get 10W40.

Also my planned OCI has moved from 3K using dino to ~12K annual since I adding the 1qt/600 miles Porsche says is normal.

edit; the only increase in leaking was when I used Val. SynPower 20W50 (PAO per MDS) and it leaked A LOT.

 

[tilley]

Thanks for the update. Let us know when you eventually get a look inside the engine.

So the QS synth is a 'group III' (severely hydrocracked) oil? And the 'group IV' PAO Val 20W50 caused leaks? Interesting.

 

[kang]

I have a 993 and I use Mobil 1 0w-40. I’ve used it for ~50,000 miles with no issues. Here’s my opinion on the whole ZDDP thing, especially as it applies to 993’s.

First, it’s claimed that lower zinc levels will wear out the camshaft on motors like the 993. I just had a hydraulic lifter replaced (with ~100,000 miles on the engine, I’m not complaining). I asked the mechanic to take a look at my cam, where the lifter rides on it, and let me know if there was any unusual wear. He said there was none.

As far as hydraulic lifters go, yes, Porsche has said they’ve seen problems with lifters when people use the heavier oil. I think I’ve also seen that on the PCA tech board. The 15W-50 is too thin at start-up to properly lube the lifters. Remember the claim that 90% of engine wear occurs at startup? Well, that applies here. Over time, the lifters wear out.

I find it very interesting that those who recommend Brad Penn also happen to sell it. I get suspicious when I see someone say “Mobil 1 will kill your engine, you need Brad Penn, oh, by the way, I happen to sell it.” Some of the people recommending Brad Penn have excellent reputations, but there is definitely a conflict of interest here. Not that there is anything wrong with Brad Penn oil, I’m sure it’s fine, but the 20W-50 stuff is certainly too thick (especially for hydraulic lifter motors). Also, some of the people who recommend it still have the old-school “thicker is better” mentality.

Someone on this thread said 0W-40 in a 993 will burn like crazy. I get between 2,500 and 3,500 miles before I burn a quart. That’s pretty darn good for a 993.

Some people think there is some conspiracy at Porsche recommending 0W-40, like it’s cheaper for dealers to only stock one oil. What do you think would happen if air cooled 911 motors, whether serviced at the dealer or not, started dropping like flys and it turned out that Porsche was aware that M1 0W-40 didn’t provide the needed protection for these motors? Can you say “class action lawsuit?” There are lots and lots of air cooled motors out there, running on 0W-40, without problems. There have probably been millions of miles put on these motors with that oil without problems.

I’m sure you’ve heard the rumors of flat tappet motors failing 300 miles after a rebuild, when using an SM rated oil (less zinc). I call B-S! If a motor fails 300 miles after a rebuild, something else was going on besides the oil used. You could probably run motor for 300 miles on vegetable oil and it would still run.

Porsche recommends several good oils in the 0W-40 or 5W-40 ranges. Stick with one of those and you’ll be fine. Put in dino 20W-50 or add a zinc additive and you could be asking for trouble.

One more thing, remember your air cooled flat 6 motor does burn some oil. Some gets into the cylinders when the car is parked. You’ve seen that puff of oil smoke at startup, right? Well, the zinc in the oil that’s getting burned off at that time is getting into your cat. Zinc can poison a cat, which is why they are lowering the levels of it in the first place. Think about this when you want to add a zinc additive, or use a high zinc oil.

Zinc is what they used as an anti-wear additive 30 or 40 years ago. Don’t you think they could come up with other, better ways to do this in that amount of time? Like someone said above, M1 0W-40 Euro oil is one of the highest sped’d oil in the world. It has all the anti-wear additives you need and more. Use it and you’ll be fine. You’ll also have less startup wear, more performance and higher mileage (due to the thinner oil) and less zinc to poison your cat.

 

[buster]

I agree with Kang. I blame a lot of the rumors about M1 on the internet and fools that know very little if anything about oil. I have spoken with a GM engineer that said they test the [censored] out of M1 and it is the "Gold standard" of synthetic oils. People just don't know what they are talking about in many cases.