[HeroOfSpielburg]

Hello,

 

I really want to make an oil change on my recent purchase since I don't know when it was last done.  I have gotten my hands on a Mahle filter and the oil pan drain plug gasket, however I'm having a hard time finding the high performance synthetics most people recommend.  I think it would be better to change the oil now instead of waiting until I can get my hands on 7L of Mobil 1 for something that costs less than a trip to the mechanic, so here are my local options for my '92 coupe with 100k km.

 

The best I can see is Castrol Magnatec C3 or Edge FST Turbo Diesel TI, both 5W-40.


Of course mineral 15w / 20w-50 is still available and cheaper than synthetic, but the car is old and as I've read runs hotter than most similar engines.


May I ask:

1) That I'm right in understanding synthetic is definitely the way to go

2) Is the Magnatec good enough or should I be looking for a zinc additive as well?


Thanks for your thoughts!

D.

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[Inkedupfatboy]

I don't run synthetic in mine. I do change all my vehicles oil every 3K.

I agree it is better to change it now, since you don't know when it was last done, which will allow you to do the research on what you want to run later.

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[banditsc]

I only run synthetics. Someone from Europe will probably chime in on what they are using.

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[Waylander]

These engines were designed and built before the real rise in synthetics, but that does not exclude their use


Take a look in your hand book and look at the rating for your temp range that will give you a guide as to grade considering where you are.


My car is quite high mileage at 143K I have run Shell Helix HX7 and high quality 15W40 mineral oil, and my car is happier on the mineral oil.


The lifters are quiter and the oil pressure higher after a long drive,


Oil is such a subjective topic and you will get a 1001 opinions but I would pick the best oil for your temp range regardless of synthetic or mineral, mainly because it will be better than the unknown stuff you currently have in the motor.


And I would avoid Mobil 1 as that has one of the lowest ZDDP counts


And that's an opinion only

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[Inkedupfatboy]

Probably get everyone upset here, but I don't worry about oil. I run synthetic in the Harley only because I only ride it once or twice a year and I got tired of changing the oil every six months because it aged out.

 

I have never had an engine fail, because I used the wrong oil. If it's oily and has the right viscosity, then I use it. I make sure the right amount is in the pan but as far as brands go, I don't care. I have had cars run for hundreds of thousands of miles and I have never had one complain it didn't like the brand oil I was feeding it. I change it every 3K religiously in every vehicle and have never had an issue.

 

I let my mechanic make that decision.

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[JTP]

I've had good experience with Motul synthetic and it's highly rated.

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[MCL968]

I thought the Mobile 1 15-50 still contained sufficient amounts of zinc. I recall reading that it was the only one that they made with the right amount of ZDDP. Anyone know if this is still true?

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[az968]

Mobile 1 15-50 has a high ZDDP level. There's a chart on Mobile'web site on their different oils and 15-50 is almost at the racing oils level.I don't know how to upload the chart.

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[flash]

having seen what happens on the insides of thee engines when running non-syntheitic oils, it is nothing but foolhardy to do that if you have a choice.  the additional wear and tear on the cams and variocam pads is easy to track.  those are expensive parts, and easy to avoid, merely by using the correct oil.

 

further, the extension of the longevity of the synthetics, makes it almost half the cost of dino oil, so even the idea of saving money with dino oil is out the window.

 

ZDDP is absolutely essential on our flat tappet lifters.

 

just because synthetics were not widely used when our engine was designed does not mean that it is not better.  it only means that it was not yet available.  we use better tires now too.  should we go back to the harder and less grippy compounds that wear out faster, just because that was what was available when the car was designed?  should we go back to the analog cell phone that the car had available?  heck, let's go back to cassette tapes too while we're at it.

 

bottom line - run synthetic.  if you can't get it when you need it, run clean oil, and change it to synthetic as soon as you can.  make sure whatever you run has the necessary ZDDP.

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[Bulti]

FWIW, I use 10W-40 Shell HX-7 (semi-synthetic) and add a bit of Cam-Shield ZDDP.  The oil is changed once a year or 15000 km, whichever comes first.  The oil pressure is well within spec (150000 km).

 

Here's a nice write-up of some oil facts: http://www.upmpg.com/tech_articles/motoroil_viscosity/

 

Interesting stuff about synthetic oils too.

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[williamoss]

I use the following

 

Red Line Synthetic 5-50 in the engine

 and Sweepco in the Transmission

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[Waylander]

Millers CFS 20W50 nano technology get good reports here with 1200ppm ZDDP

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[Chris Vais]

I've been running Total mineral oil, which has a a high ZDDP content, on the advice of my mechanic. The car now has about 160K miles on it and no issues with the engine. Total is a French product.

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[Bulti]

It's pretty amazing how few people use the viscosity the manufacturer recommends. For example, 10W40 has a range from about -13 to over 104 °F. Why bother using a different one? Street use off course.


Not necessarily something wrong with what people use, but why take the risk using something that could be less good?

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[SamSparks]

Years ago Porsche, when servicing my car, put a large tag on the car's dipstick. It is still there. It says: 'Only Use Mobil 1'.

 

When I was in doubt about which particular oil to use, I phoned a trusted Porsche centre - they said use Mobil 1 0W-40 synthetic. So I do. I change it - and the filter (Mahle) once a year no matter what.

 

If it were me, and I were in Sweden, I'd do the same - call a respected Porsche Centre and ask them. I'd be wondering if the extreme climate in Sweden (as compared to the UK) required a different grade.

 

Lycka till!

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[Waylander]

I have to say that in the UK manual 0w40 does not get any kind of mention, I would suggest that the OPC is just going by the A30 recommendation with out looking at the correct spec for the car


the other issue with 0W40 is that it is an SM API oil and has less than 800ppm ZDDP, I think I would check that with your OPC again or even better give an indie that knows these cars a ring, JMG, HARTECH, and see what they have to say



OPC these days have probably not seen an FE Porsche for ten years

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[az968]

The different viscosities may also have different levels of ZDDP. Forexample, Mobile 1 0w40 has ZDDP of 1100 ppm, and meets the Porsche A40 rating, while the 15w50 has 1300 ppm and a recommendation for flat tappetengines, like the 968. Also, the manuals for the 968 were written over 20 years ago, before many of these modern oils were developed. I don't know if the manual would apply today. My mechanic likes 15w50 in my 968. But I need to know more.

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[SamSparks]

Interesting stuff. A quick google and I found this from the Mobil FAQs: 'Mixing motor oil to reach the right ZDDP level for classic cars' - here's the link. Excerpt: "Mobil 1™ 0W-40 already contains a higher level of ZDDP (1,000 ppm) that could benefit your flat tappet engine"

 

I take the point about OPCs. I did however make a point of speaking to the head mechanic at the OPC in question - the only (I think) OPC actually owned by Porsche GB in the UK. But yes, further verification does seem like a good idea.

 

Just checked the Mobil UK website - for the 968 they recommend MOBIL 1 NEW LIFE 0W-40 (which is what I am using).

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[Waylander]

It's the API SPEC that says it all


the ZDDP level was down to 800 ppm in API SM licensed oils. This was mandatory for API licensed oils that were SAE 10W-30 or less. Diesel oils are typically 10W-40 or higher, so these viscosity grades can contain up to 1200 ppm ZDDP in accordance with the API CJ-4 Diesel engine oil standard. However, all of these oils have had increased levels of detergents and dispersants since the late 1990s. This allows for longer drain intervals and helps to keep engines cleaner when they are forced to use exhaust gas recirculation to limit emissions.


If I read that correctly, which I might not


If the oil reaches API SM then it must be less than 800 ppm to meet the standard below 10W30, does that include or exclude 0w40?


API SL was 1000 ppm

So I guess rule of thumb look for oil that meets SL


The other issue is the balance between detergents and ZDDP

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[SamSparks]

Opie Oils in the UK (largest independent retailer of performance oils) list the following for a 968.

 

Seems they believe 5W-40 fully synthetic is the way to go.

 

Re OP: They list Castrol Magnatec 5W-40 C3 Fully Synthetic Engine Oil

 

From Castrol Sweden website:

 

REKOMMENDATIONER

FABRIKAT: Porsche MODELL: 968 (1991 - 1994) TYP: 968 CS (1991 - 1994)

Din rekommenderade motorolja

Castrol Magnatec 5W-40 A3/B4

Användning: Normal (Byt 20000 km / 12 månader)

 

Mobil Datasheet 2014 showing ZDDP levels etc.

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