Mobil 1: Mixing Viscosities = ?

[donv]

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.

[Doug H]

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

[donv]

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!

[Brucelee]

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

[Doug H]

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

[Perfectlap]

Went to Wal-Mart an noticed they had 5 quart jugs of Mobil 1 ($23) in all weights but 0-40 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?