Mobil 1: Mixing Viscosities = ?
 

Was looking over my stocks to do an oil change this weekend. In looking at the oil on hand, I've somehow ended up with 2ea of the following 5 Quart/Litre containers of M1:

• 15w50 "Extended Performance" (Gold cap)
• 5w40 "Truck & SUV" (Silver cap).

I remember buying the 5w40, as there was no "European Car Formula" to be found at any store at the time. I drive three season only, so the 5w## part didn't worry me. But I have no idea how I got the 15w50, and no receipt to return it even if I did.

Soooo, is there any way to mix these (say 1 of each) and stay within Porsche specs/get best usage range, if I'm a three season user? Obviously, risking the engine isn't worth ~$50 of oil! However, if it is a simple 50:50 mix = 10w45, this would be within the owner manual's recommendation of up to 15w50 at "generally higher than 50 degF/10 degC", with more flexibility on the low end for some of the colder days in fall and better protection on the high end for a summer DE.

It is not recommended to mix oil viscosities. Just take the one back to a store you frequent, and ask the clerk if you may make an even exchange. Should not be an issue as long as the bottle is unopened and clean and a current stocked item in that store.

M1 Viscosity blending
 

Hello Don V,
there is not a problem in mixing Mobil 1 viscosities. A viscosity calculator can be used to proportionally blend the required viscosity very accurately

However the two you mention are very different animals as the 5w-40 (T&SUV) (Delvac 1 5w-40 or M1 Turbo diesel Truck 5w-40) isa Group 4/5 blend and a great product. Mobil 1 0w-40 is a very similar product to the T&SUV 5w-40

Mobil 1 15w-50 is not a Porsche Approved viscosity

This is my first post in this Forum having sold the last of my 928 S4 and purchased a Boxster

I hope this helps
Regards
Doug

Thanks for the replies. I will probably just try to get a store to swap the 15w50 for either more 5w40 or the 0w40 Euro car formula.

FWIW, per my owner's manual, 15w50 is listed as acceptable for temperatures "generally higher than 50 degF/10 degC".

Doug, welcome to the forum!

Before the 0-40 was available, the 15W-50 was the oil of choice for Boxsters.

Hello Rich,
0w-40 lubricants have been available for well over a decade now and no 15w-50 engine lubricant has been Approved by Porsche since a little before 1999

The first synthetic lubricant factory filled by Porsche was a 10w-30 (1992) which was dicontinued in favor of a 5w-40 (1993). 0w-40 and 5w-40 viscosities have been the factory fill since then (with very few exceptions)

Of course one can use any engine lubricant they wish

Regards
Doug

Went to Wal-Mart an noticed they had 5 quart jugs of Mobil 1 ($23) in all weights but 0-40 :mad: One quart was $6
But I noticed there was a bar code on the shelf for the 0-40 5 quart container.
anyone ever seen one of these?

Yes, they do have that from time to time.

WM is very poor at keeping oil on hand.

I frequently notice the Truck and SUV 5W40 Mobil 1 and have wondered if its related to the Delvac One series, and if it would be any good in the Porsche. Since Diesel oils tend to be very good at suspending particles (soot in the case of Diesels) one could argue it would be an advantage for a car with a longer drain interval.

Patrick

Delvac 1 5w-40 engine lubricant
 

Hello Patrick,
the Delvac range of lubricants is tailored for Commercial use. I have extensive experience with Delvac 1 5w-40 engine lubricant in a variety of engine families and for around a decade or so. Its close relatives were/are M1 SUV 5w-40 and M1 Turbo Diesel Truck 5w-40. It is a Group 4/5 lubricant with around 25% ester content

I used it in all of my Series 60 Detroit Diesel engines (12.7ltr, 500hp, 1650ft/lbs) over many years. I averaged 60k (miles) OCIs using Used Oil Analysis. I authorised a tear down inspect on one engine after 1m kms (620k miles) and all wearing parts met Detroit's reuse parameters. Hone marks were still visible on the wear surface of each liner

I used Delvac 1 5w-40 in my MY89 928S4 for around 50kkms over five years. Ten UOAs were progressively published on another Forum. I will publish the last (No 11) when I get the results in the next week or so if you wish

I also use it in a wide range of other petrol engines and it was in my MY98 2.8 Z3 BMW for around 60kkms

It is not an Approved Porsche oil as it is a mixed fleet HDEO. It would exceed all of Porsche's test protocols

Many believe that it (Delvac 1 5w-40) is one of the best engine lubricants ever made and my experience tends to confirm this

I have no affiliation with any Oil Company

Regards
Doug

Doug-

That pretty much sums up my own thoughts as well, non Porsche approved, but probably better at the same time. I've run Delvac 1 in several Ford and GM turbo diesels with great results.

Nice thing is you can often get it wholesale at the Mobile Will Call window.

Patrick

where is this Mobil will call window you speak of?

I think if I go to Wal-Mart one more time and stand on one of those snail pace lines one more time...

p.s.
called Mobil and 0-40 is no longer being sold in 5 quart containers.

Look in the hone book or Google for your nearest Mobil Oil and Lubricants distributor. Some of them are cool, and others will hassle you about having a wholesale account with them and a resellers permit bla di bla, but if t they're cool it will save you a bunch.

Patrick