Adding 10w40 to make higher 10w30 M1

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Sep 15, 2002
Scottsdale, AZ
Considering a 5qrt sump, would 1qrt of M1 10w40 added to M1 10w30 be enough to make it higher on the 30 side or 2 qrts? In other words, a 4 to 1 ratio or a 3 to 2 to make the difference?
***Is this a sane thing to try? The engine "seems" to be clicking since switching to M1 10w30. I'm thinking this might help. The truck is due for a scheduled maintenence (120K) so I'll check for clicking after but thought I'd throw this question out there.

[ January 21, 2003, 06:01 PM: Message edited by: Toy4x4 ]
Thanks Ferrari,
They don't! Guess that answers my question!


Sorry for the posted

[ January 21, 2003, 06:06 PM: Message edited by: Toy4x4 ]

Mobil makes an excellent 10w-40 synthetic "motorcycle" oil. This stuff is SJ/CF rated, so there would be no problem running it in a car. The high temp properties are better than the M1, 0w-40. If I had to guess, I'd bet the TBN is higher as well and that it's more shear stable. I've seen this oil at Walmart for about $6.75/quart, so it probably uses very high quality basestocks....
Thanks Al,
I was just going to ask that question (since I went to Mobil's site and found EXACTLY what they DO make
). Would be nice if the 10w30 was higher in the 30 range.
Would Delvac 1 5w40 also be a contender for this? (Does it even come in quarts?)

Any numbers/specs available on that M1 10w40?
This seems like a lot of trouble to do this, but M1 is readily available and the next full syn choice is Royal Purple which is more expensive. I'll have to see, too, if Walmart starts stocking the cheaper 5qrt jugs of M1 like they said they were.

[ January 21, 2003, 06:49 PM: Message edited by: Toy4x4 ]
The popular combination for LS1 owners seems to be 2qts M1 15w50 with 4qts of M1 10w30. Nobody has done oil analysis yet though, but this combo yields them much lower oil consumption and quiets or eliminates the piston slap. I'm sure the final viscosity ends up being somewhere in the high 30/low 40wt range. Hopefully an Ls1 owner who is doing this combo will get an oil analysis done (I've begged them to please get one done, and slowly but surely I'm convinced some LS1 guys to do oil analysis)
For hot running 4cyl's, would you go with M1 10w-30 or 0W-40? I'm thinking about summer.
These seem to be Mobil's most shear stable oils.

[ January 21, 2003, 07:59 PM: Message edited by: buster ]

Originally posted by buster:
For hot running 4cyl's, would you go with M1 10w-30 or 0W-40? These seem to be Mobil's most shear stable oils.

I think most 4 cylinder engines, at least the imports, have tighter clearances and would benefit more from a low to mid 30wt oil. We'll see with my wife's Honda, as her last oil was Mobil 1 5w30, which was around 10.2 cst, and her current oil is Royal Purple 5w30, whose virgin analysis showed 11.5cst (mid 30wt)
Mobil 1, 10w-40:

Flash Point, 487F
Pour Point, -65F
Viscosity @ 100C, 13.8 Cst - I think this is actually good, since you don't want something too thick in an engine toleranced for a xw-30 grade. So this would be preferrable to a 15-16 centistoke, 15w-40 diesel oil.

The extreme temp properties are what caught my eye - I'd imagine the high temp evaporation is very low for this stuff.
Patman, can you briefly explain the cst number? I'm not quite sure what this means. Sorry..

These were Mobil's 0w-40, 0w-30, 5w-30, 10w-30, 15w-50.

Cold Cranking, cP @ °C
Cold Pumping, cP @ °C
Kinematic, cSt @ 40°C
Kinematic, cSt @ 100°C 4,301@-35°
14.4 3,800@-35°
10.1 3,600@-30°
9.7 3,848@-25°
9.8 5,234@-20°

[ January 21, 2003, 08:30 PM: Message edited by: buster ]
For reference, this is the 3VZ-E V6 (sorry, forgot to post this).

Thanks Tooslick for those #s.

How do these options sound:
Either one of these a viable/correct option?

Down here, factory fill for the 3VZE is 20W-50 dino.

My last 3 oil changes have been
* redline 10W-40
* M1 0W-40
* Currently Delvac 1 5W-40.

There was a little top end noise on the 0W-40, that's not there with the Delvac.
Shannow stop copying my oil habits!! After I finish this 80/20 Delvac 1/0W40 TS blend (yes quieter than straight M1 0W40) I'll try Redline 5W40 which I have on order. Probably mix with a quart or 2 of RL 5W30 for the winter.
my deepest apologies for copying.

Hmmm, still got a litre of the me an idea for next change.

Originally posted by buster:
Patman, can you briefly explain the cst number? I'm not quite sure what this means. Sorry..

In order to determine the second number in an oil's viscosity (the 30 in 10w30 for instance) they measure the oil's viscosity at 100c (since this is a typical oil temperature once an engine is fully warmed up) So here are the following specs which show the range of each viscosity:

20wt=5.6 to 9.29 cst at 100c
30wt=9.3 to 12.49
40wt=12.5 to 16.29
50wt=16.3 to 21.89
60wt=21.9 to 26.09

So when you choose an oil it makes sense to pay attention to the specs to see if the oil you choose is going to be on the thin or thick side of it's particular viscosity rating. Also pay attention to the virgin and used oil analysis reports on here to see it's actual viscosity as measured when new and when put into use (to see if it tends to thin out or thicken up)
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