10W40 Synthetic Blend (My Recipe)

[Oldwolf]

I have not found any information indicating that mixing a synthetic and mineral oil will cause any problems. In fact, Mobil says on their website it is OK with their oils.

Putting 8 quarts of synthetic in my MB (1993, 602.962, 2.5L Turbo) is costly, especially given a 5000 mile OCI. My engine is turbocharged so I am changing at this interval because “the manual says so” and also because am a little concerned extended OCI’s may lead to damaged bearings in my turbocharger.

I have been using Delvac 1300 15W40, a fantastic oil and highly praised by the HDEO crowd on this website, but winter is coming and I’d like to lower my oil weight for the winter driving season.

I bought 8 quarts of Mobil 1 Turbo Diesel Truck 5W40 thinking that I would use 100% of it for my next change.

I am now considering a 50% Delvac / 50% Mobil 1 Turbo Diesel Truck blend that would yield a 10W40 oil (approximately), an adequate weight for winter here in North Carolina. This blend gives me the some of the advantages of the low cost Delvac and of the high cost Mobil 1 Turbo Diesel Truck synthetic.

On a side note, another thread I have discusses if a CF rated oil is all I need for my engine. If it is, I may try the Mobil 1 15W50 mixed with Mobil 5000 5W30 (both CF rated) in a 50/50 blend to get a 10W40. But only if you guys say I am on the right track.

I am really interested to hear what you guys think about this.

 

[addyguy]

You could save yourself the hassle probably and just run something like Rotella T Synthetic 5w40 in your rig.

 

[D-Roc]

Originally Posted By: addyguy
You could save yourself the hassle probably and just run something like Rotella T Synthetic 5w40 in your rig.


There is no fun in that...doesn't sound like he's bothered with it.
As for the original question, I can't see any problems...

 

[Oldwolf]

RTS is $19/gal vs $22/gal for the M1. Pretty close.

No hassle... pour in 1 gal of one and pour in 1 gal the another.

 

[007nomad]

I have been thinking of doing something similar, what did you end up doing, and did it work out ok?

I have a 2005 Cummins 5.9 and was using Rotella T 5W-40 CI-4.
I like the idea of synthetic for winter starts as well as for the turbo.

Now the CI-4 oils are generally not avalable but I did find some Delvac 1300 15w40 CI-4.

So I was considering mixing the Delvac dino CI-4 with Rotella T syn CJ. This woudl be very different additive packages.
Thoughts?

 

[bbslider001]

I guess my question is "why"? Seems like a big PITA....whatever makes you feel more protected. Any of the Big 3 will do just fine, in fact, more than fine.

 

[m37charlie]

What's the lowest the temperature gets in your area?
If over -4F. (-20C.), just use 15W40 and let it idle for 2-5 minutes when below +20F.

Charlie

 

[Rand]

honestly I wouldnt use 15w40 below 10F.. its like honey at 10F


I suspect you would be fine as long as the oils have similar additive chemistry's otherwise the oil might not hold up as well as 8qts of either oil by itself.

 

[007nomad]

0F is as low as I am likely to see, though -10 to -20F is possible.

 

[m37charlie]

One of the definite specs of 15W40 is viscosity And 60000 is very thick but 6600 is pumpable.
+10F. is absolutely no problem for 15W40, at least modern grp.II ones that have pour points of -30 to -33C. (-26 to -31F.)

Charlie

 

[roadrunner1]

i'm looking at the deere spec for their 15w40 plus 50 and they say 4`f, but i have started as cold as -20`f with this oil in several different diesels, they didn't like it, but they started.
i am switching to deere 10w30 plus 50 for the winter (and maybe beyond) in my 6.0 powerstroke for better pumpability in sub-zero temps

 

[Oldwolf]

This weekend it is supposed to get to 27F. That's pretty cold for us.

 

[m37charlie]

Originally Posted By: Oldwolf
This weekend it is supposed to get to 27F. That's pretty cold for us.


Hate to repeat myself but anything above 0F. isn't a problem with a modern 15W40 (the kind with a pour point around -30C.) Just let it idle for a little why. You can tell how long with the oil pressure gauge. When the oil is really cold the pressure will keep rising as it warms and pumps better. When or just before it peaks you can go; after that it gets thinner as it warms.

Charlie