N51

When I purchased my car, nearly 2 1/2 years ago, it came with Mobil 15W-50.
I stayed with it until the required oil change and then switched to Amsoil 5W-40. My oil consumption increased from 1qt/4000 miles to 1qt/3000 miles. I've run Amsoil in my Ag diesels for 2 1/2 decades with excellent results. Their marine diesel oil has a good package of additives for engines that set for ten months out of the year. I've no complaints.

However, a recent service interval had my local shop switch to Mobil1 0W-40.
While i expected increased oil consumption, based on the Amsoil experience, that has not been the case. Consumption is now 1qt to 8000 miles, maybe a little more. I'm delighted, as I've run the car harded than ever - full spirited upshifts and downshifts. It's never run better. Good news is always welcomed with these older cars.

For those of you who've made the switch, I'd be most interested in your assessment.

Many thanks,
Noah

Gary R.

While I still run 15-50 M1 Extended in my track car I have run 0W-40 in my 964 since I bought it. It's coming up on it's 1st oil change (6000 miles) and I have not added one drop.

ltc

Porsche now recommends M1 0W-40 as the 'one size fits all' motor oil of choice.

N51

Gary,

Thanks for another data point. I was being most conservative in my evaluation of the 0W-40 - it's more like 9000 miles to a quart. And most generous to the Amsoil - it drank it like water. LOL

Lewis,

I was aware of the Porsche recommendation, just didn't think there would be such variance between the two oils, given my past experience. Apparently there is a difference between tractors and Porsches. :-) Now, nobody post a picture of a Porsche tractor.

Noah

SimonExtreme

The oil consumption shouldn't be greatly effected by grade but more by the make up of the particular type of oil. The types of oils are

Mineral Oils
Hydrocracked/Molecularly modified mineral oils
Poly alpha olefins (PAO) (Synthetic)
Esters (Synthetic)

I will only use a full synthetic oil. They last longer and protect better. From my personal experience, you will get better consumption from a synthetic oil.

M1 is a PAO fully synthetic. You can improve on that with a PAO/Ester mixoil suxh as Silkolene PRO S 5w-40 which is what I use and with which I saws great improvement in oil consumption compared with Castrol RS 10/60. The Castrol was used by a well known Porsche specialist and is a real "con". Although it says on the can it is synthetic, it is actually a hydrocracked oil which, due to a court battle, is allowed to call itself "synthetic" (at least in the UK).

The amount of protection you get from the different types of oil is incredible. The rating only gives you a viscosity at a certain temperature and gives you no view on how much protection you will actually get from the oil.

As an aside, running thicker oil is not only not needed but it increases fuel consumption and reduces power.

Christer

I use the Castrol RS oil and didn';t know it wasn't synthetic. Mind you, I guess if it is good enough for the the M3 and M5 then it might be OK...? I think I will try the Silkolene Pro S next time....and at £40 for 5 litres I guess it should be good.

SimonExtreme

Christer,

Castrol RS (now replaced with Edge Sport) is not recommended for BMW's! I thought it was but the BMW's use a different oil which is a proper synthetic. The BMW one used to be called TWS 10w-60 Motorsport Engine Oil (now replaced Edge). I am unsure whether the new Edge Sport is a genuine synthetic or not.

In addition, while I know that Castrol RS 10w-60 isn't a POA or ester oil (not a proper synthetic) I cannot remember whether the 0w-40 version was. All I know is that I was very suprised that a well known Porsche specialist used Castrol RS 10w-60 which I have now learnt is the wrong grade as well as not being synthetic.

I was also shocked when you posted that the oil cost £40 for 5 litres. I bought a case about 15 mony=ths ago and paid £27.50 each! I hadn't realised engine oil had gone up so much. Having said that, good old Castrol RS equivelent is now £36 or more so the oil change will cost £8 more! Worth it, I think.

Bearclaw

"M1 is a PAO fully synthetic."

M1 has been shown through some recent VOA's to contain some Group III basestocks. Hard to say if all their products do, but a lot of people have their shorts in a knot over this. But does this mean M1 is not a darn good oil? Of course not. But I have to say, I wouldn't be as quick to put it into my P-car knowing this.

A lot of people love German Castrol (the green stuff) which is a full synthetic Group IV/V and now available in the US. I have several vehicles and use a variety of synthetics, looking for the holy grail. The fact is, one 'good-quality full synthetic' is probably as good as another.
I've been using Redline 5W-40 in the Saab's and AMSOIL Euro 5W-40 in the Volvo's. Been using Valvoline Synpower 20W-50 in the 964, but the Redline will probably go in the next time around.

tgage

I noticed the engine was much quieter at idle. I recently switched from dino to 0w-40 @45,000 miles. No oil leaks, and the engine appears to run cooler.

Excuse the hi-jack. I'd also like to switch the gear oil over from (oops...mobil1) to Mobil delvac which I think is a rename for mobilube SHC...but I'm not sure where to buy it. Any ideas (or alternatives)? I've seen someone post the following URL, but it seems odd I can't find it in a city the size of Atlanta.

http://www.lufteknic.com/Merchant2/m...ode=lubricants

bgiere

Lufteknic is the place...It is hard to find here. They ship quickly!

SimonExtreme

I hadn't heard this before but it goes to show how much of a minefield this whole business is. It amazes me that companies can get away with claiming oils are fully synthetic when they are not but that is exactly what happens.

I wilol only use a fully synthetic POA/ester blend our and agree with the comment that the car runs quieter on the "good stuff" I personally use Silkolene Pro S. I guess the next thing to do would be to send a drop of my old oil away for analysis.....................

Cuppie

According to a Mobil rep I spoke to at Goodwood, we should be using Mobil Motorsport 15-50W, designed for engines with bigger oilways.

0-40W for modern engines with smaller oilways that need less viscous oil on start up......

warmfuzzies

Hmm,

That's weird Mel, the reps at my OPC on an open night recommended the 0W 40 for us older types.....


Simon,

Are you anything to do with Opie oils???

Kevin.

SimonExtreme

Wrong Simon! I am only a customer but am repeating some stuff from them and stuff from some other oil specialists I know. When Opie first told me about the Castrol RS situation, I didn't believe them so I checked elsewhere.

Mel

It's interesting what is said by different people! The original Porsche handbook for my car states that 15w-50 should only be used in summer. I have been told by a fair number of people that 5w really is as thick as one should or need to go on the cold side and that you don't need thicker than 40 when warm. I believe that Porsche have now changed their view on what is best and no longer recommend the thicker oils, even for summer only

Cuppie

Well I'm sticking with Mobil Motorsport!!