Dear friends:

Do you believe using diesel oils (with its extra additives) in gasoline cars may adversely affect catalytic converters and potentially cause emission control failure? Is there any confirmed evidence of this relationship? Thanks.

Eric

How much diesel/gas ratio do u plan to put into your gas engine?
Don't think a gas engine will run on dsl. I tried ran dsl in my 2 stroke lawn mower, she ended up thrown a rod!


Small amount maybe Ok, but if the catalytic gets plugged then is another few bills.

Hello SD300,

No, I mean using diesel engine oils (CH4, CI4 etc.) to replace the regular gasoline engine oils (SH, SL etc.) in gasoline cars.

Eric

in the sump not the tank!

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I have two different brands of diesel-rated 15W40 oil on the shelf. The label on one brand makes no mention of the oil's suitability for use in gasoline engines. The other brand claims the the oil "provides outstanding protection in 4-cycle gasoline engines."
But as long as diesel and gasoline rated oils are both available, I am going to use them in the application for which they were intended.

used rotella in many of my gas engine cars, but i have no idea if it might detrementally affect the cat. i suspect not but have no actual knowledge.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Well, ANY oil is better than no oil at all if you're stuck somewhere and are low...

As for the additives, maybe they are bad, maybe not. Does your gas engine burn that much oil that it will matter? Yes, some amount of blowby happens all the time, but in tiny amounts, and after being combusted, I don't think things are that sensitive. If you're getting enough blowby for the additives in the oil to mess up an emissions test, I'll bet you have other problems (ie: bad rings) and a gas engine oil probably won't be that much better.
Now, the viscosity might not be what you want in a gas engine. 15W40 could be a bit thick on startup. Getting oil to the bearings as soon as possible is one of the big things you can do to prevent wear. Most places sell a 10W40 oil if you want the extra viscosity in your gas motor when it is warm.

From what I've read via http://www.bobistheoilguy.com/ diesel rated oils have better cleaning agents, a higher resistance to oxidization and other stuff I can't recall.

There have been people using these oils in the crankcases of gas engines to help clean out crap. (example Isuzu Trooper 3.2 v-6 engines are prone to gunking up)

I use a "C" rated oil in my Tr6 as the car doesn't get driven daily and of course sits all winter. I'm using it as it the oil won't oxidize as much as the car sits idle.

To this point I've never had any problems using "C" rated oils in my Tr6.

Aivars Berzins

I have yet to see a C-rated oil (diesel-rated) that also isn't S-rated (gasoline-rated). But only a few S-rated oils are C-rated.

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

I use Amsoil 15W-40 in everything I own. Lawnmower, cars, anything internal combustion. Diesel rated oil has a more robust additive package that is more resistant to acid build up and has a higher detergent factor. Oil rated for gas powered stuff cant handle the diesel environment and the soot load that diesels must deal with.

Use it with peace of mind.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

To answer your question:

There are some oils that have both diesel and gas ratings, but the new SM is not desiged for diesels. Diesel rated (C) oils have more zinc dialkyldithiophosphate, an anti-wear additive. Zinc dialkyldithiophosphate shortens catalytic converter life and gasoline rated (S) oils (especially SM) have much less. Diesel rated oils ususally have more phosphorus as well - another additive that is not good for catalytic converters.

__________________
1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer

This MIGHT be true IF the oil ever makes it into the combustion process. An engine in good shape, however, will keep the oil in the crankcase or in circulation and will not allow it to enter the combustion chamber.

I have probably a half million miles worth of using Chevron Delo in gas engines with GREAT success.

There are many active threads on this subject right now, so I'm not going to repeat myself in this one due to time constraints.

Have a great day,

I use diesel oil in my motorcycle, but I don't think that counts, there's no cat on it.

__________________
5 speed '91 190E 2.6 320,000 mi. (new car, fast, smooth as silk six, couldn't find any more Peugeots)
5 speed '85 Peugeot 505 2.5l Turbo Diesel 266,000 mi. (old car, fast for a diesel, had 2 others)
5 speed '01 Jetta V6 (new wifes car, pretty quick)
5 speed '85 Peugeot 505 2.2l Turbo Gas 197,000 mi. (wifes car, faster, sadly gone just short of 200k )
5 speed '83 Yamaha 750 Maxim 14,000 mi. (fastest)
0 speed 4' x 8' 1800 lb Harbor Freight utility trailer (only as fast as what's pulling it)

I've been using gasser oil in my car since the day I got it...

that's not bad, is it?

__________________
1982 240D.
My name is Michael, and I am an 18 year old binge-drinkin', cigar-smokin', novel-writin', all around unsavory and unnattractive guy. I tell long-winded stories, and I only shave once a week, although I've had to do it every day since I was 16.

Glinko,

If you are changing it frequently you probably haven't done any permanent damage, but your engine will last longer and do better with one of the oils blended specifically for diesels. These have a CI4 classification. Examples are; Shell Rotella T, Mobil Delvac and Chevron Delo 400. These three are the most common, but there are many others.

Good luck,