How would M1 0W40 compare to Amsoil 10W40 as far as extended OCI's? Extended for me would be about 12,000 or 1 year in a 4.0 Jeep. Soon I'll be able to do a UOA on the M1 0w40 that is in it at it's 5000 oil change.
The best extended drain Mobil 1 product is going to be their 10w-30, Supersyn. The 0w-40 isn't nearly as shear stable and uses the same basic additive chemistry. It won't offer you any better protection or performance. The M1, 10w-30 uses little or no VI modifier, so the engine will also stay cleaner, even with long drain intervals.
If this engine is in decent shape, I'd also recommend running the highly friction modified, Amsoil Series 2000 instead of their 10w-40. Again, the 0w-30 is going to be more shear stable (it uses a even better VI modifier), and it's about 10% thinner in terms of HT/HS viscosity.
Your peak oil temps will run 5F-10F lower with the 0w-30 - a very good thing in Florida - and fuel efficiency will be about 3% better then w/ the 10w-40. The Jeep 4.0L engine responds very well to the type of borate FM's that Amsoil uses. I think it will be more cost effective to use than the 10w-40 - even with a drain interval of only 12k miles:
12,000 miles @ 20 mpg = 600 gallons of fuel
600 gallons @ $1.50/gallon = $900.00 of fuel annually
3% fuel savings with the Amsoil 0w-30 = $27.00 saved annually.
Price difference in seven qts of the 0w-30, vs seven qts of the 10w-40 is approx $17.50 annually. ( Assumes a six qt initial fill and one qt makeup oil)
Note: I'd actually recommend buying the Amsoil 0w-30 in a case of 4, one gallon containers (TSO-04). This saves you fifty cents per qt over the same oil sold in a case of qt containers. When you see how well it works in this application, you'll want to run it again ....trust me on this one.
[ November 27, 2003, 06:07 AM: Message edited by: TooSlick ]
TooSlick, the 4.0 is very healthy and has never used any oil. But it does seem to like 40wt oil. When I first got it I tried Rotella T 15W40 with good results but the phos. scared me. I thought it might harm the cat. Then I tried M1 5W30 and the motor seemed to "loose". Then went to M1 5W30 and 15W50 50/50 mix for a few changes before the 0W40 became available. It seems to like the 50/50 mix and the 0W40 a lot.
I have a case of 5W30 ASL here at the house and might try an OCI with it if it is a heavy 30wt. Though I still like the idea of a xxW40 in that motor.
KW - you are very smart to recognize that your vehicle will thrive on a XW-40. The UOA's that I have looked at for 4.0's are a world apart between a 30 and a 40.
You are in Florida? Synthetic 15W-40 is great bet for your set-up, and one of Amsoil's best values.
Flrodia means an automatic 40 weight to me ( Unless you race a lot then 50).
MOBIL1 0w-40 can be run year 'round there,.. I have to agree with its unsuitabilty for extended drain, if you extended drain, then the 10w-30 is indeed the better choice despite its other disadvantages.
These are what I believe would be your best choices for the Jeep
1. Delvac 1 5w-40
2. Amsoil 5w/10w-30
3. Amsoil 15w-40 AME
4. Mobil 1 10w-30
S2k is only 11.2 cSt oil too thin IMO for this engine. This engine likes a high 30wt/40wt oil.
Also, this comming spring Mobil is bringing out a 5w-40 SUV oil which would be excellent for this engine. It most likely will be Delvac 1 rebottled.
[ November 27, 2003, 02:50 PM: Message edited by: buster ]