"Diesel" oil in a gas engine?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

RockDoc

RockDoc

10 Year 15 Year
Joined
Jun 3, 2007
Threads
118
Messages
7,242
Location
SW MB CA
Title pretty much explains it. What is special about "diesel" oils and is there any reason not to run them in a gasser? Will the soot dispersants do anything counter-productive? Any advantages to a "diesel" oil? Any differences in TBN/acid buffering? Or is it all marketing to the main group consuming a given grade? :confused:

Now that I have a dual filter set-up (https://forum.ih8mud.com/60-series-wagons/191368-amsoil-remote-oil-filter-mount-good-idea.html) I want to put some good quality synthetic in there, and many of the good oils, gradewise, are "diesel" formulations.

I am thinking of using AMSOIL with a bit of Redline mixed in (to be sure there is an ester component), and changing over half the capacity at 6 months/6-8,000 miles, varying the fresh component between 5W40 and 15W40 with the changing seasons.
(If anyone is wondering "why not just change it all", poke around here: Synthetic Oil Life Study It appears that wear indicators rise most dramatically right after an oil change, and less rapidly after that. See the AMSOIL trends here: Amsoil Test Results and the Mobil1 trends here: Mobil 1 Test Results The iron and copper values tell the story.)

Thanks for your opinions, :popcorn:
Curtis.
 
Last edited:
I have run mobil mx"diesel" oil in every engine I own for the last 3 years. that is my mini truck, my diesel Landcruiser, my V8 Landcruiser, my honda mower and weedeater. I also live in a hot part of the world, diesel formulations are generally a bit thicker so you wouldnt want to run them in a cold climate

Paul
 
Most diesel oil is non detergent, and non energy conserving. Why would you go there?
 
I have run Rotella 15w40 in everything i own for about 6 years now. no problems. 4 trucks (diesel and gas), 7 mowers, utility vehicle, etc.

it is easier to just buy one kind than to have a shelf of 5 different weights and brands that go in different things.
 
If the oil you're thinking of using is an "S" rated oil, ie: SE or SF or similar then it has been tested to meet the requirements of a gasser oil. The further down the alphabet the second letter is the more stringent requirements are met. Diesel oil is all "C" rated.

The "S" stands for spark ignition and the "C" for compression ignition.
 
Thanks cruiser_guy, that'll help a bunch.

So something with the following ratings would be fine in a gasser?
• API CJ-4, CI-4+, CH-4, CF
• API SM, SL, SJ..
 
RockDoc said:
Thanks cruiser_guy, that'll help a bunch.

So something with the following ratings would be fine in a gasser?
• API CJ-4, CI-4+, CH-4, CF
• API SM, SL, SJ..
Click to expand...

If it has both those ratings it is equally well suited in both gas and diesel engines. It's not uncommon for a higher quality oil to have both ratings. The Chevron Delo 400 which I use in my truck has both ratings as well.
 
I think a lot of it is marketing. According to Mobil 1, the current 5w-40 "Turbo Diesel Truck" formulation that is for sale is rebranded Mobil 1 Delvac, which is no longer marketed in the US apparently. They are now marketing Turbo Diesel Truck as premium grade 5w-40 that can be used in mixed (gas and diesel) fleets. Works great in my turbo Subaru and my FJ62.

API Ratings: API CI-4 PLUS/CI-4/CH-4/CG-4/CF-4/CF/SL/SJ

Mobil 1 Turbo Diesel Truck 5W-40

Comparing Mobil 1 Turbo Diesel Truck 5W-40 to Mobil Delvac 1 5W-40
 
S="spark" ignition rating. SM is the most current rating, I think the FJ60s only required SD or SE when new.

Most diesel oils are "mixed fleet" oils, suitable for gas and diesel engines. They are excellent oils in your Land Cruiser.

I like the Chevron Delo 15w-40 myself most of the year, and run the Shell Rotella Syn 5w-40 in the winter.

As to them being non-detergent oils---well, that's just incorrect information.
 
New think that I learn about oils .. S and C

I ran 20W-50 in all my cruisers .. 2 are turbo diesel and 1 it's a gasser .. coz in " diesel " oils the jump from 15W-40 to 25W-60 it's huge and the last one it's pretty thick.
 
Tapage said:
.. coz in " diesel " oils the jump from 15W-40 to 25W-60 it's huge and the last one it's pretty thick.
Click to expand...

25W-60?!?!?! I've NEVER heard of engine oil that thick. That's just a little thinner than gear oil at 75W-90!
 
I recently purchased to Pure Power reusable, cleanable full flow oil filter (Pure Power Oil Filters High Performance Motor Oil). I was going to go Amsoil dual remote as well but just don't have the space. The head guy at Pure Power, a chemist, had nothing but bad things to say about synthetics and any weight under 10. Mostly he felt that the additive packages sucked. I've always used synthetics with excellent results so switching back to dino juice is hard. However I likely will switch this weekend (next oil change) to Shell Rotella (non syn) which he highly recommended. I'll probably keep my Audi's on Mobile 1 however.
 
Thanks for all the replies guys. :cheers:
I think I am a bit more edumacated now.
 
jfnall said:
I have run Rotella 15w40 in everything i own for about 6 years now. no problems. 4 trucks (diesel and gas), 7 mowers, utility vehicle, etc.

it is easier to just buy one kind than to have a shelf of 5 different weights and brands that go in different things.
Click to expand...

Shell Rotella 15/40 and a Wix filter. I swear by this combo and have run it in everything from a 1-6L Turbo Miata to my current 4.0L Turbo Cruiser. Rotella Rocks!
 
I'm always a little wary when a "chemist" makes negative remarks about another product.

There is substantial evidence that quality synthetics provide better lubrication of moving parts in almost all circumstances. Think about it, when car manufacturers do not want you to use synthetics until your engine is properly broken in, that says something.

Other manufacturers require synthetics be used since the highly variable dino-oil is not of sufficient consistency or quality to provide proper lubrication in the given application (eg Volkswagen).

In my past experience, most re-useable oil filters are not all that great. It's kind of like using a K&N style air filter on your off-road truck - which is akin to placing an oiled fly screen in front of your air intake. On the linked site, there's all kinds of brag about billet this, and stainless steel that, but nothing of filtering capacity, mesh size etc. in the text. Makes me kind of wonder.

And back to the original thread: diesel engine oils are usually higher in detergents and higher in total TBN. Generally speaking, you are getting a better quality oil when you use a diesel formulated oil. They are suitable for use in all engines, as long as the viscosity is correct for the conditions.

And, regarding the comment about any oil under 10W being suspect: that is just plain nonsense. Several manufacturers (eg Honda) now require light oils since they are machined to such fine tolerances that heavier oils will not properly lubricate the parts (and void their warranty).


~John
Who uses spin-on filters and synthetic oil in his diesel


Moby said:
I recently purchased to Pure Power reusable, cleanable full flow oil filter (Pure Power Oil Filters High Performance Motor Oil). I was going to go Amsoil dual remote as well but just don't have the space. The head guy at Pure Power, a chemist, had nothing but bad things to say about synthetics and any weight under 10. Mostly he felt that the additive packages sucked. I've always used synthetics with excellent results so switching back to dino juice is hard. However I likely will switch this weekend (next oil change) to Shell Rotella (non syn) which he highly recommended. I'll probably keep my Audi's on Mobile 1 however.
Click to expand...
 
When I had my engine (2F) rebuilt, the machinist said the new oils, synthetics included were mandated to remove Zinc to meet EPA guidelines. Zinc is an 'extreme pressure' additive and is critical for flat-tappet break-in. LINK

He gave me an addative, made by GM, that he said adds the zinc and manganese back. He also said to use Shell Rotella because all Diesel oils still have the Zinc and Manganese in them for extreme pressure applications.

Newer cars without push rods or solid lifters don't need the pressure additives. Cars/Trucks with solid lifters do.

Rotella or equivalent is the way to go.
 
Spike Strip said:
When I had my engine (2F) rebuilt, the machinist said the new oils, synthetics included were mandated to remove Zinc to meet EPA guidelines. Zinc is an 'extreme pressure' additive and is critical for flat-tappet break-in. LINK

He gave me an addative, made by GM, that he said adds the zinc and manganese back. He also said to use Shell Rotella because all Diesel oils still have the Zinc and Manganese in them for extreme pressure applications.

Newer cars without push rods or solid lifters don't need the pressure additives. Cars/Trucks with solid lifters do.

Rotella or equivalent is the way to go.
Click to expand...

That's definately something to look into. Is the zinc important after break in? I'll have to have a look at the analysis data for the AMSOIL stuff.

*Edit* As of 2003/2004 (the analysis link in the first post) AMSOIL's 5W30 had s***bags of Zinc and Magnesium (as opposed to Manganese, I suspect Magnesium is the addative). Know when the EPA rules came in?
 
Last edited:
UpsideDown said:
In my past experience, most re-useable oil filters are not all that great. It's kind of like using a K&N style air filter on your off-road truck - which is akin to placing an oiled fly screen in front of your air intake. On the linked site, there's all kinds of brag about billet this, and stainless steel that, but nothing of filtering capacity, mesh size etc. in the text. Makes me kind of wonder.
Click to expand...

I definitely agree. I use a CM (Canton Mecca, CM Filter, Home Page) Filter in my Subaru. They advertise filtering to 8-micron. The filter is ~$100 and rebuild parts are ~$25, so it's much more expensive than disposables. I began using it because of its 25k element life span...I was putting a lot of miles on the car and didn't want to hassle with changing the filter at every oil change. Given the awkward positioning of the FJ62 oil filter, I may consider a CM Filter for it as well, but only for its longevity, not its filtration.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom