FYI Motor Oil 20W-50, NFG & not factory approved, see page 111 of Owner Manual

[guru944]

To all:

Realizing all these numerous post with oil pressure and motor oil issues and repeated engine oil related failures over the years, I felt in necessary to clarify the truth....and provide OEM Documentation to support this level of understanding and Fact See page 111, 1987 Porsche 944, 944S, 944 Turbo Owners Manual for details.

The summation is this fact: 20w-50 was never an approved weight for the 944 platform (968 turbo S/RS) from Factory production and racing programs in North America and Europe from 1985-1995. It is listed as one of the "Multigrade Oils" and not a "Fuel Efficient Oils " weights (10w-30, 10w-40) approved from the factory. see Oil Table from pace 111 for visual reference.

In my manual, I have reviewed pages 110-111 and Yellow highlighted the relevant information that is critical to us keeping our closely regarded vehicles running. Attached are the pics from my Owners manual for your review (Documented).

" This is no Jedi Mind Trick" or scam....

*** Recommend we all post mark this for references and clarity.*** Later...

[JD159]

Sorry guru but wrong.

1) Porsche would not put the multigrade oils in that chart if they did not approve them.

2) The fuel-efficient oil passage is just a more in depth explanation of the category of fuel efficient oils.

3) Your misinterpreting what Porsche is trying to convey when they state:

"Porsche approves only fuel efficient oils which are structurally so stable that they can be used in Porsche engines in both winter and summer yadada."

What this statement means is NOT that Porsche approves ONLY the use of fuel efficient oils (which they do not, as they approve the use of 20w50 multi-grade oils), BUT instead that the ONLY fuel efficient oils in which Porsche approves are oils that are so structurally stable. Oils that do not have the necessary stability are not approved as Porsche approved fuel efficient oils.

You are misinterpreting the semantics and grammatical structure of the statement by claiming Porsche only approves fuel efficient oils. They only approve fuel efficient oils THAT ARE SO STRUCTURALLY STABLE, and, multi-grade oils like 20w50.

4 years of Philosophy and dissecting crazy complicated theories and propositions, as well as advanced logic courses that made me turn paragraphs into formulas, has taught me how to correctly interpret sometimes confusing statements.

As an aside, Porsche only approves mobil 1 now. Which is clearly because the superiority of the oil and how great it is at preventing wear . When I called Porsche years ago before I did my homework when I first got my car, Porsche said only use mobil 1. So, going firmly by what Porsche says, may not necessarily be the best decision. Do your own research!

[zedsn]

From the chart looks like 10/30 is good from -10 F to 70 F and 10/40 maybe 80 F. I don't know about you but I drive my car in the spring and summer months only and at times in 90 + degree weather with a turbo motor as well. I have always used 20/50 dino oil during my ownership and the guy before me used 15/50 synthetic in my motor and at 145K hard miles I still have my original bearings.

[flash968]

JD - bang on

really have to be careful about thinking in absolutes.

those charts are all but worthless. they are only there as a guideline. you look at your normal temp range of ambient temp, and choose accordingly.

as an example, redline upper oil temp limit is 15 degrees higher than royal purple, but 10 degrees lower than amsoil, all in the same 10-40.

synthetics can tolerate more temperature than dino oil, and last a LOT longer. a multi-viscosity dino oil is all but worthless on a high mileage engine. there is so much gunk in there that in a very short time it is too dirty to extend to the higher viscosity rating. synthetics don't suffer from that problem as much.

it's not black and white

[sausagehacker]

Building on what flash pointed out, most manufacturers publish kinematic viscosity levels at 40C and at 100C. Comparing these values will give you a better idea of the fluid properties than a simple SAE grade.

For example, Redline 20W50 is 19.8 cSt @ 100C and Castrol 20W50 is 18 cSt @ 100C. Both have the same SAE 50 rating at that temp, but are still different. The base stock composition will also affect longevity and other fluid properties outside of viscosity, but that's another topic altogether...

[TibetanT]

Good discussion!

However, what is really funny about this....who in there right mind would drive any car with a human being inside when the atmospheric temperature is above 60 degrees Celsius, let alone 100 degrees Celsius. Do you know how hot that really is? (Hint: boiling point of water approx. 212 degrees F, or 373.15K)

Saudi Arabia gets to be about 45 degrees Celsius at times during the summer months as does the Outback, down under.

Back to Earth...we are however, talking about the heat build-up within an engine, a Porsche engine so it is relative that these engines would see temperatures that high especially on the race track. Statistically speaking engineers are required to calculate MTBF, so I do understand why this is stated within the owner's manual.

[9FF]

guru944, you are reading everything out of context and preaching it to be the only truth! Isn't that how we got to have so many religions? In fact oil is a religion for some on car forums

[v2rocket_aka944]

Originally Posted by TibetanT

However, what is really funny about this....who in there right mind would drive any car with a human being inside when the atmospheric temperature is above 60 degrees Celsius, let alone 100 degrees Celsius. Do you know how hot that really is? (Hint: boiling point of water approx. 212 degrees F, or 373.15K)

Saudi Arabia gets to be about 45 degrees Celsius at times during the summer months as does the Outback, down under.

Saudi Arabia? Outback?
You should visit the general Los Angeles area on an unremarkable July-August day. 40 celsius is "pleasant beach weather."

There is a direct correlation between coolant temps (therefore engine temps) and oil pressure (due to oil thinning), something very apparent in the 944 cars. So with that in mine, 20W-50 is all I run year-round.

[TibetanT]

Originally Posted by v2rocket_aka944

Saudi Arabia? Outback?
You should visit the general Los Angeles area on an unremarkable July-August day. 40 celsius is "pleasant beach weather."

There is a direct correlation between coolant temps (therefore engine temps) and oil pressure (due to oil thinning), something very apparent in the 944 cars. So with that in mine, 20W-50 is all I run year-round.

I think you either missed my point, or forget the important part of my thread, so here:

Back to Earth...we are however, talking about the heat build-up within an engine, a Porsche engine so it is relative that these engines would see temperatures that high especially on the race track. Statistically speaking engineers are required to calculate MTBF, so I do understand why this is stated within the owner's manual.
__________________
BTW< Just for the record books, I use Mobil 1 15W-50 Synthetic during the Summer month's here in Eastern Washington when it is HOT, and 5W-30 Mobil 1 Synthetic during the Winter months. Not much driving during the Winter months due to salt and chemicals being put on the roads when the snow starts piling up. We, Northerner's, have to adapt or suffer the consequences.

Cheers!

[sausagehacker]

Originally Posted by TibetanT

I think you either missed my point, or forget the important part of my thread, so here:

Back to Earth...we are however, talking about the heat build-up within an engine, a Porsche engine so it is relative that these engines would see temperatures that high especially on the race track. Statistically speaking engineers are required to calculate MTBF, so I do understand why this is stated within the owner's manual.
__________________
BTW< Just for the record books, I use Mobil 1 15W-50 Synthetic during the Summer month's here in Eastern Washington when it is HOT, and 5W-30 Mobil 1 Synthetic during the Winter months. Not much driving during the Winter months due to salt and chemicals being put on the roads when the snow starts piling up. We, Northerner's, have to adapt or suffer the consequences.

Cheers!

I think the point of stasis is where those temperatures are manifested....

It's true that higher outdoor temps generally push engine temps higher because of warmer air past the radiator (although a properly maintained cooling system mitigates this), but the primary factor in the oil's temperature is the engine temperature. The only other opportunity to take on/pass off heat is the oil cooler, which is an exchange with the coolant... also primarily affected by engine temp. So while ambient temperature affects oil temp for the initial startup, the operating temperature demands an oil with an appropriate viscosity given engine/bearing geometry and volumetric oil flow rate.

[TibetanT]

Originally Posted by sausagehacker

I think the point of stasis is where those temperatures are manifested....

It's true that higher outdoor temps generally push engine temps higher because of warmer air past the radiator (although a properly maintained cooling system mitigates this), but the primary factor in the oil's temperature is the engine temperature. The only other opportunity to take on/pass off heat is the oil cooler, which is an exchange with the coolant... also primarily affected by engine temp. So while ambient temperature affects oil temp for the initial startup, the operating temperature demands an oil with an appropriate viscosity given engine/bearing geometry and volumetric oil flow rate.

Point taken.

Thus, why I prefer synthetic oil; properties equate to better protection of engine components in the long run!

[flash968]

yup - i was a dino oil guy forever. then i actually learned something about oils, and now will never run dino oil in anything, especially something with some miles on it.

[Toran]

What oil are you good people using in your 944 these days?

[flash968]

amsoil 10-40

[944 Ecology]

Don't confuse me with the facts, my mind is made up!

[flash968]

roflmao - it's hilarious just how touchy this subject is. 9FF hit the nail on the head. it's very much like religion. no matter what your position, you won't sway somebody from theirs.

[cockerpunk]

Originally Posted by TibetanT

Point taken.

Thus, why I prefer synthetic oil; properties equate to better protection of engine components in the long run!

yup, always full synthetic in all my cars. 944 takes 0w-40 and the mr2 with 2zz takes 0w-20, 5k mile change intervals.

Originally Posted by flash968

yup - i was a dino oil guy forever. then i actually learned something about oils, and now will never run dino oil in anything, especially something with some miles on it.

first sensible thing i have seen you post!

[alfadoc]

[pfarah]

I've been using Castrol High Mileage 10W-40 Synthetic Blend with no issues. I also change my oil around 2k - 2.5k.

[911tracker85]

JD

4 years of Philosophy and dissecting crazy complicated theories and propositions

I was a math major and my room mate was a philosophy major. when he was taking a 'logic' class and get stuck on an argument, I would convert the various phrases to symbols and then turned the whole think into a symbolic logic equation to solve.

OK, I'll take my turn getting flamed on this topic.

I have been using Mobil 1 syn 15W-50 for years. and have read the flaming posts about Mobil 1 VS amsoil (which I use in my old Honda) VS Brad Penn, etc over the past few years.

was an interesting situation when Dave Lindsey suggested straight Joe Gibbs dino oil for my 951 DE car. still breaking in the rebuild so have not been to the track with it yet. and I also installed a 3X oil cooler and high capacity aluminum radiator.

from what I think I understood, synthetic is great for high temps, 'normal use' and longer change intervals.

but considering when these engines were designed, PROPER dino oil with proper zddp and other additives needed for these cars, keeping oil temps down, and frequent changes (as in every track event) he recommends dino for track duty.

it is interesting that Porsche now sells a couple varieties of oil specific to the older, air cooled cars, and if I read the add correctly in Excellence it is dino, not synthetic.

here is a link to the Joe Gibbs site. lots of charts, graphs, chem analysis stuff.
Why Use Driven Racing Oil? | Driven Racing Oil