adam_

Where to start....

what makes oils different isn't just the "5W" or the "10W" or "50" numbers... they are not simply different only due to viscosities. All the discussions on most of the lay forums are all about those numbers, but that is only a minor factor in what makes the oils different.

Even the same brand- say a Mobil 1 0w40 and a mobil 1 5w50 could have entirely different stabilizer chemistries, and even base compositions.

It is not like mixing blue and red to get purple!

You should NEVER mix oils.

jcb-memphis

I emailed M1 and they say one can mix 5w-50 and 0w-40. In my opinion, sticking to one oil is way better. But, if you are running low and need to add oil and don't have what you need around, getting it up to the right level with something approved in my opinion is better than running low.

Lesson to be had...keep a quart in the trunk of your favorite stuff. For DE days...take one extra quart or so per day....2 if you are using 0w-40. I use 5w-50 and find it nice on the track and street doing double duty. My back-up oil is 5w-40 turbo diesel truck branded M1.... After that it is a 5w-40 by Elf or some other good brand on the P car list.


JB

adam_

Surely you CAN add oils to ensure you do not run out, but the question for M1 is "as a matter of long term use, is mixing A+B permissible and will not degrade the overall performance of the oil".

Carlo_Carrera

I understand mixing blue and red to get purple is different to mixing oils.

The oils might not fully mix and could separate in the engine.

My question is will they separate?

Will the heavier grade sink to the bottom in the engine if the car sits for a while?

jcb-memphis

http://www.mobiloil.com/USA-English/...scosities.aspx

Carlo_Carrera

Sweet, so you can make a 7.5w-45. Not that I am going to, but it is good to know.

kkswow12

and then there is the price of this stuff in germany...like, i don't know, at least 17 euros a liter, gawd...still a deal for what it does, but it just don't seem fair...

Kevinmacd

Mac, love your thoughs but I think you really are not on track! At the same warm up temps 5w-50 and 15w - 50 will flow the same. as far as sophisticated hydraulic systems don't fool yourself, there are other engines out there with the same basic principles as the Porsche variocam plus system, and they use different oil specs. So don't think that persepctive holds up!
The main differences in the M1 5w-50 and 15w-50 other than a little more ZDDP, is the
5w-50 has Porsches approval for long life as speced with BMW and Mercedes. Yet the
15W-50 also has the Mercedes spec. Personally after looking into this for some time, looks to me this is Porsches answer to the multiple climates Porsches are shipped to. Rather than spec multiple oil grades it's easier to spec two that cover the majority of the low temps in some regions vs. the high temps in others.

Tytus

I find all of this fascinating. My independant P mechanic who only services P cars for everyone from collectors to DE drivers and racers has recently switched to 15w-50 Motul in the last year or so. He says since M1 has been reformulated he doesn't trust it. He recommends the 15W-50 Motul for all his air cooled and older water cooled cars, especially 996 Turbos that are tracked, such as mine. I have had no issues, track my car 15+ days a year and drive through the winter and change my oil often, depending on track days but at least every 2,500 if tracked to 5,000 miles max if not tracked. I put 12,000 mi/yr on the car.

Additionally the car does not burn, use, drip or sweat oil. When I first got it 1.5 years ago it had 42,000 miles and sweated a little oil at the very rear of the engine. Now the car does not sweat oil at all, dry and clean bottom of the engine.

So, am I lucky, is my engine being damaged, or is the Motul product better than M1? I don't know but the car has 58,000 miles now and runs great.

What is the potential damage to the engine if I keep running the 15w-50 motul?

Tytus

Kevin

Tytus >> which Motul product? 300V? A cold day in spring of fall might create wear. If you look at the big budget race teams they preheat the oils. For climates outside of Florida and Baja, running 15W might cause some tappet/vario cam issues. There is alot of drag placed on the IMS that is required to turn ALL the multiple oil pumps. At 60 degrees you can really see how thick 15W is vs 0W and 5W.

Carlo_Carrera

Well it depends. Do you keep your TT in a warm garage overnight in the winter? If you do then I would say you are not risking much wear on start up in the cold weather.

You are as a counter point very well protected against wear at the track in hot weather.

A shop I go to uses 15w-50 in all Porsches if they are going to the track but also recommends going back to 0W-40 in the winter.

It is really your call. Since you putting on a lot of miles annually you could easily time your oil changes to go to a thinner grade in the winter.