Diesel Oil in a Gasoline Passenger Car ?

[eljefino]

Originally Posted By: Merkava_4

What happens to a diesel engine when it's being subjected to a gasoline PCMO ?


My 300D OM.617 owners manual included the first 100k of oil change service. They ran "Mercedes 20w50" with no indication of it having a diesel rating.

Furthermore the manual doesn't mention the diesel specs-- in fact, it thinks 10w50, if you can find it, is what you need.

It's 32 years old and still tight. When I rest the oil cap on the valve cover to test for blowby it just sits there; many "dance".

 

[HerrStig]

Originally Posted By: Merkava_4
What about cleaning ? I've heard some guys say diesel oils are loaded to the hilt with detergents. Does a diesel oil clean as well as a synthetic ?
Can a Diesel oil BE a synthetic? Do you have some kind of post quota to meet?

 

[HerrStig]

Originally Posted By: wemay
I'm using T6 because it was $9 a jug at KMart.

I use it in three cars, two bikes, a mower, snow blower, and genset.

 

[ExMachina]

Maybe the diesel oils will handle soot better in a gasoline DI engine, right?!

 

[aquariuscsm]

As long as I've been here I'm like Merk,the whole "diesel oil" (meaning the dual rated HDEO) thing has always confused me a bit. If diesel oil is superior,then why not run it in all gasoline engines?

Are there any cons whatsoever to running an HDEO in a gasoline engine? I read on alot of various car forums just to get info,entertainment,etc,and I've read a few times that HDEO's have detergents (to keep diesels free of soot) which can be harsh to gasoline engines. Fact or myth?

In fact the smoothest running oil I've ever used was Royal Purple "diesel" 15W40 Synerlec (which they don't make anymore,right?). I scored a few cases dirt cheap years ago someplace.

So in conclusion,if HDEO's are superior in every way,why do PCMO's even exist?

 

[Pontual]

Just look at UOAs and VOAs, Diesels don't have more detergents. What they have is more Dispersants (succ anhydride and PEA don't show up in the VOA/UOA), to cope with higher soot content.

 

[ExMachina]

Originally Posted By: Pontual
Just look at UOAs and VOAs, Diesels don't have more detergents. What they have is more Dispersants (succ anhydride and PEA don't show up in the VOA/UOA), to cope with higher soot content.


Current gasoline DI engines do generate a lot of soot. Possibly good for that.

 

[HerrStig]

Originally Posted By: aquariuscsm
As long as I've been here I'm like Merk,the whole "diesel oil" (meaning the dual rated HDEO) thing has always confused me a bit. If diesel oil is superior,then why not run it in all gasoline engines?

Are there any cons whatsoever to running an HDEO in a gasoline engine? I read on alot of various car forums just to get info,entertainment,etc,and I've read a few times that HDEO's have detergents (to keep diesels free of soot) which can be harsh to gasoline engines. Fact or myth?

In fact the smoothest running oil I've ever used was Royal Purple "diesel" 15W40 Synerlec (which they don't make anymore,right?). I scored a few cases dirt cheap years ago someplace.

So in conclusion,if HDEO's are superior in every way,why do PCMO's even exist?
"Harsh"?

 

[Donald]

Originally Posted By: Merkava_4
Any advantage to that ? I notice alotta guys on here running diesel oil in their passenger cars. One dude is even running Mobil Delvac in his Infinity. I can understand the need for added zinc and phosphorous in older cars with flat bottom lifters, but there's guys on here running it with their roller lifters too. There's gotta be something I'm missing. Clue me in.

Some oil has a "S" rating along with a "C" rating. Oil with a "C" rating is typically called diesel motor oil. But if it also has an "S" rating that is spec'ed for your car, your fine.

 

[pezzy669]

HDEO in a gas car for cleaning - absolutely!

An ex of mine had a '02 Toyota Celica with the 1ZZ-FE 1.8 which was used extensively for work which involved ~30k/annually driving, let's just say it had 'sporadic' oil changes (dear ex was a typical head in the sand Toyota driver) that ranged from 7,000-14,000 miles on whatever swill the local jiffy lube would put in. 135k on the clock and the dipstick was almost entirely covered in varnish, shockingly it had no oil burning issues and no visible sludge under the oil cap and it still got a cool 40 MPG in all freeway driving.

Anyhow I was appalled at how poorly this Celica was treated from a mechanical standpoint (dear ex was sure it still got it's 2x annual detail though) so I put it on a diet of Mobil Delvac 1 5W-40 @ 5k intervals for ~25k miles. Varnish was about 90% gone by the end of the "cleaning". Car was sold at 185k miles with no visible leaks and zero (imperceptible) oil consumption.

I will say I don't think the Toyota 1ZZ-FE cared for the heavy oil too much, compared to the standard 5W-30 it called for you could definitely feel it was far more sluggish and the VVT steps became very noticeable. Surprisingly did not notice too much of a fuel economy hit.

 

[Pontual]

Originally Posted By: ExMachina
Originally Posted By: Pontual
Just look at UOAs and VOAs, Diesels don't have more detergents. What they have is more Dispersants (succ anhydride and PEA don't show up in the VOA/UOA), to cope with higher soot content.


Current gasoline DI engines do generate a lot of soot. Possibly good for that.


Good point.
Once I read that diesel spec oil are harsh it the detergency/dispersacy side with affinity to corrosion on yellow (brass seals and sockets) and pink metals (copper) for car/bike/boat/plane gasoline engines, but never saw a fundamentated study to convey on that one. Same story on the use of pcmo in avgas engines. The detergents would eat the so called soft metals. I'm not convinced of that, though. I know airplanes can't handle ZDDP sice they are natural burners, but the "cleaners" problems are another suff.

 

[chrisri]

Originally Posted By: HerrStig
First, let's define "Diesel oil". Then, perhaps, we can discuss what may cause the sky to fall if we use an oil rated for gas, Diesel, and motorbike use in our gas powered vehicles. I've yet to see a label which days "For combustion ignition ONLY" on a jug of oil, but THAT I wouldn't use in my spark ignition vehicles. I've got some old cans of Castrol 20W 50 which say "CD" on them. One could say THAT was using GAS oil in a Diesel.

In Europe all HDEO are single rated, diesel only oils. Only PCEO are dual rated. I'm using HDEO in one petrol /gasoline car for twelve years, and can't see any problem with it.

 

[rvt]

Personally I stick to spec or near spec oils for my vehicles. But then I'm on top of the maintenance. I've known people who are grossly neglectful of their engines here in so. CA. Triple factory OCI recommendations. If you had to pick an oil for that service..what would it be? I'm thinking Mobil1 0W40 or some of the synthetic HDEOs (delvac 1 esp). Even a 15W40 conventional. Maybe extra viscosity buy a bit of extra protection for cam chains in grossly neglected engines-after all else fails.

 

[Merkava_4]

Originally Posted By: aquariuscsm
As long as I've been here I'm like Merk,the whole "diesel oil" (meaning the dual rated HDEO) thing has always confused me a bit. If diesel oil is superior,then why not run it in all gasoline engines?

Are there any cons whatsoever to running an HDEO in a gasoline engine? I read on alot of various car forums just to get info,entertainment,etc,and I've read a few times that HDEO's have detergents (to keep diesels free of soot) which can be harsh to gasoline engines. Fact or myth?

In fact the smoothest running oil I've ever used was Royal Purple "diesel" 15W40 Synerlec (which they don't make anymore,right?). I scored a few cases dirt cheap years ago someplace.

So in conclusion,if HDEO's are superior in every way,why do PCMO's even exist?


Aquarius, you should've been the OP of this thread. You ask better questions than I do.

I too remember hearing somewhere about HDEO's being harsh on gasoline engines because of all the extra detergents. Puts me in mind of Purple Power whenever I have my hands in it. That stuff stings my skin just like if I had my hands in floor wax stripper. I think it's basically the same stuff because they both have the same chemical smell. That floor wax stripper actually takes your skin right off if you're in contact with it long enough. I remember one time when I was living on the boat, there would always be a 5 gallon can of Blast-Off floor wax stripper laying around. One day I got the bright idea to use one of those 5 gallon cans as a temporary seat. There was a little bit of stripper on top of the can, which I didn't realize until it was too late. The stuff burned a hole right through one of my butt cheeks causing it to swell up and turn into a giant blister. After a few days, that blister turned into a callused knot and so I actually had to go to sick bay and have them cut it out with a scalpel. Learned my lesson about harsh chemicals that day.

 

[Garak]

Originally Posted By: aquariuscsm
As long as I've been here I'm like Merk,the whole "diesel oil" (meaning the dual rated HDEO) thing has always confused me a bit. If diesel oil is superior,then why not run it in all gasoline engines?

Some avoid it for the same reason that my dad did - fuel economy penalties. They're small, but in a fleet, it adds up. Some are worried about their cats, too.

As for RP's Synerlec 15w-40, I do know their 15w-40 is now CJ-4. I don't know if the Synerlec is still there. They also have another line of HDEOs, but I don't know much about them off the top of my head.

With respect to your question about why PCMOs exist if HDEOs are superior, I'd agree with you, at least with respect to certain grades. I see absolutely no use in North America for a 10w-40 when we have a fantastic variety of 15w-40 and 5w-40 HDEOs. A 15w-40 isn't a perfect, drop in replacement for a 0w-20, for obvious reasons. However, I can't think of many situations where I'd prefer a 10w-40 over a 15w-40 or 5w-40 or a 0w-40.

I wouldn't worry about any "harshness" in the least. They still are dual rated, and a modern E7, E9 or E6, E7, E9 lube have lower SA than various older PCMOs and A3/B4 type lubes. Also, an E6, E7, E9 lube will have low phosphorous, somewhat akin to an ILSAC lube.

 

[Merkava_4]

Garak -- this may be a little bit off topic, but is Mobil 1 0W-40 one of those ILSAC oils ?

 

[Garak]

Certainly not. It's HTHS is >= 3.5, so it won't qualify. Additionally, there are no 40 grade ILSAC oils. They're all 30 grades and lighter. Of course, as I've already mentioned, I can easily buy a 0w-30 or a 5w-30 that is thicker at operating temperatures than the 10w-30 you're using.

 

[aquariuscsm]

What's the difference in say,Castrol GTX 10W40 and Castrol Tection 15W40? How different is the base oil and add pack?

 

[Kamele0N]

GTX is for passanger cars...

Tection is HDEO for trucks...

What first comes on my mind is higher TBN value...

 

[SR5]

Keep going Merkava-4 and Aquariuscsm, I don't get it either. You two are asking all the good questions.

Is it just a price thing? If HDEO was the same price as good PCMO would everybody still run it? I keep hearing of the great price you pay for Rotella T etc (we don't get it here so I don't know for sure). Is it just you get more bang for your buck with HDEO?

What if HDEO was a little more expensive? Would it be worth the premium price ?

Thanks for sharing your knowledge.