tool

So I pull my truck up to the shop today, whip the drainpan under it and cdrop the oil.

Puttering around while the hot oil is draining, grab a new filter off the shelf, so forth.

Grap my jugs of Dello 5W40 Synthetic and one feels light......

Somebody has topped up a tractor or something and not told me.......

So I'm short a couple litres and I have allready dropped the oil. I spun a new filter on added my Dello and the topped up with a couple litres of Rotella 15W40 Dino that I run in the summer. (I HAVE to drive the truck in the morning) Is this ok, or will the different grade of oil and mixing dino/ synthetic cause a problem.

My feeling is it's likely just fine.

any input?

Dieselnick

You shoudn't mix oils or oil brands for that matter. But doing it for one change shouldn't have any effect in the long run Also, it would be better to run the same oil year-round

Nick

tool

Hmmm, what is the theory behind running the same oil?


I just swithced to the synthetic because I figure after 40,000 miles should be decently broken in.

And most maufactures recomend differnt oild depending on the operating conditions and temperature.......

IE, here in January it can be as low as -40, in July it could be +95 so that is a big variance and would call for a diiferent oil. Hence the 15W40 vs 5W40 switch.

I guess I'm curious about a reason WHY you shouldn't do it.... Under any other circumstance I wouldn't have done it just out of habit but was caught offgaurd........

dozer12216

Military standard insists motor oils must be conpatible even synthetic. The engine could care less.

BearKiller

^^^Remember that old commercial ??^^^


The oil makers offer partial synthetic blends and "full" synthetic.

It's my understanding that the term "synthetic" itself means derived from crude-oil and anything made of synthetics is a by-product of oil refining.

I don't think the engine will ever know the difference.

Dieselnick

It's OK to switch oils every so often, just don't switch continuously. All oils have different additive packages that may or may not be compatible. As you know, when oil is drained, not all of it leaves the engine. When you refill with different oil it's additives may not be compatible with the residual oil in the engine. That's what I've always been told anyway.

Nick

DBLR

I run 5w oil year round and our temps can be from -20 below zero or colder in the winter to upper 90's in the summertime and I've not had any problems. But if you were to heavy haul all summer then I can see you wanting to use the 15w in the warmer temps.

Dieseldude4x4

In most cases, the dino will just dilute the synthetic and should not cause any issues at all.

wurkenman

I cant see where your oil would differ from Amsoil, but Amsoil staes that it will mix with ANY oil.

wannadiesel

Won't hurt anything.

HOHN

OLD WIVES TALE

The "residual" oil left in the engine when you drain is PRECISELY why oils are compatible with each other!

There are no additives in oils that will react with each other in a negative way. The polymers used for soot dispersal don't affect the ZDDP and Moly used for anti-wear or EP agents, and neither affects the calcium used for TBN and detergency.


Mix away. Your engine will be just fine.

JMO--not any more valid than anyone else's....unless I have logic and evidence to back it up

Dieseldude4x4

YEP, what he said.

Dieselnick

I stand corrected. Just trying to be of some help.

Nick

Oilguy

No worries... You can use a different oil at each oil change through out the life of the truck and it will make no difference... You just need to change the oil regularly.

tool

Thanks oilguy, I knew you would chime in.

Generally speaking I would not have chosen to mix the Dello and Rotella, but had to!