True Diesel Oil in Petrol Applications

[B320i]

Over time, have read about the apparently unsuitability of diesel-only rated oils for use in gasoline/petrol engines. Using a dual-rated product has been the suggestion for anyone wanting to run diesel oil and reap the benefits of a (supposedly) stouter oil with a better/stronger additive package.

If you decided to run diesel-only oil in a petrol engine, would there be detrimental effects in the long run, or would a "diesel only" oil actually produce noticeable benefits for OCI, sludge, wear-protection and son?

 

[jongies3]

I don't see why there would be negative long term effects, at the end of the day, an oil's job is to lubricate and help cool the engine by evenly dissipating heat. Although, there can be consequences of running petrol oil in a diesel engine because it doesn't have the right additives for injectors and suspending the higher amount of contaminates created by diesels and the higher amount of blow by.

Why you'd run it in a gas engine is beyond me. Oil technology has gone so far, top brands have great additive packs, and very robust base stocks so there's not much benefit in running a diesel rated oil in this day and age.

 

[Shannow]

The "diesel engine only" oils with no dual rating are very very different beasts to the mixed fleet oils, which are quite a bit closer to their petrol companions.

e.g. you used to be able to get Delo CXJ here in Oz 15W40, 15.1cst at 100C, 0.17% zinc, and 2.0% sulfated ash.

Back in the day, they were "known" to cause pre-ignition causing deposits around the perimieter of the combustion chambers.

 

[dexos]

Diesel oils have a better additive pack, but there's no problem to use them in petrol engines.
Actually even oils with commercial designation 'Diesel' or 'Turbo Diesel' are suitable for boths applications (petrol/diesel).

 

[KL31]

I've wondered this too. If someone was running without any emissions related equipment, then what other issues might there be?

Edit: The general train of thought is, if it can protect a massive truck engine operating for extremely long periods and a petrol engine oil could not do this, then wouldn't diesel rated oil be superior?

 

[UltrafanUK]

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Originally Posted By: dexos
Diesel oils have a better additive pack, but there's no problem to use them in petrol engines.
Actually even oils with commercial designation 'Diesel' or 'Turbo Diesel' are suitable for boths applications (petrol/diesel).


They don't have a better add pack and it's a daft idea to use them in a petrol engine as they might have incompatible seal conditioners.

Most diesel only (Acea B4) oils have slightly higher levels of Calcium detergents (Ca is better than Mg or Na based detergents in a diesel) and some have high levels of Zinc that might be an issue for a petrol engine CAT.

Some B4 oils like Shell Ultra 5w40 do have a slightly different viscosity to their equivalent petrol equivalents, although that often relates to approvals or recommendations the oil has.

 

[FCD]

I'm pretty sure it's been demonstrated that using Diesel only rated oils in petrol engine increases cylinder bore wear , also if your engine has catalytic converters it might be a bad idea because they have much more Zinc and Phosphorous which harms Catalytic converters. just stick to Dual Rated oils, also what car do you have?

 

[B320i]

Originally Posted By: "Shannow"
Back in the day, they were "known" to cause pre-ignition causing deposits around the perimieter of the combustion chambers.

Would this be a result of the higher levels of ash in the additive package?

Originally Posted By: "UltraFanUK"
They don't have a better add pack and it's a daft idea to use them in a petrol engine as they might have incompatible seal conditioners.

If its not better, then its just different, I suppose?

By the way, I think the member posting what you responded to was indicating more towards products like M1 TDT 5w-40, along with dual-rated diesel oils.

Not sure about seal conditions, but I think its a fair bet that different manufacturers would probably use different (substantial or not) rubber seals to meet the needs of their application. Some are more durable than others.

Concerns over catalytic converter wear are moot if the engine isn't burning oil. If a vehicle burns enough oil to damage cats, I imagine that would be the least of the owners worries...

Originally Posted By: "FordCapriDriver"
also what car do you have?

The query is just a general question, unrelated to any future oil usage decisions in my vehicle (a '93 E36 BMW), although a fair question given the usual "What oil?" threads we get.

 

[chrisri]

If you are referring to a single rated ACEA Ex commercial oils they are not recommended for use in petrol cars. Excessive SAPS level in some Ex specifications' can cause spark fouling, preignition, detonation and premature wear on CAT.

In reality I have used full SAPS (1.6%) oil in a petrol car (1.3 ohv, escort from 93) for at least 110-120k km up until the body disintegrated from the rust.

At 190k engine was in great shape, arguably better than the rest that used Fords or A5/B5 or even A3/B4 oils. Only speculating here, but this engines were fairly popular here, and most were pretty bang up by 200k.
Car had zero possible problems mentioned before with use of commercial oils except it didn't pass emissions. I wouldn't relate that to the oil IMO.

 

[B320i]

Originally Posted By: "chrisri"
If you are referring to a single rated ACEA Ex commercial oils they are not recommended for use in petrol cars. Excessive SAPS level in some Ex specifications' can cause spark fouling, preignition, detonation and premature wear on CAT.

THAT is incredibly interesting. Am at present figuring out an issue with pinging on my vehicle (see previous post). Used Rotella T6 on a short interval, no issue. Using a BMW-approved, ACEA A3/B4 Full-SAPS oil with a strong zinc package, what you post makes me wonder if the oil *could* be causing my problem. No consumption, aside from my (almost) religious checking of the oil every week or so.

 

[SR5]

A typical high SAPS Euro A3/B4 oil, might have a TBN of about 11.5 and a SAPS of about 1.25% This is at the top end for PCMO's with ILSAC or C3 oils being a lot lower.

Kendall ILSAC 10W30 has a TBN of 8.0 and a SAPS of 0.96 %

Looking at a Diesel Only - Shell Rimula 40 grade oil, it had a TBN of 15.9 and a SAPS of 1.9%. That is a lot, and I believe it's due to the high detergent & dispersant level required to deal with the large soot loading in a commercial diesel engine. I believe the concern is the additives coming out of solution and causing contaminates to form in the combustion chamber.

 

[supercity]

Originally Posted By: UltrafanUK

Most diesel only (Acea B4) oils have slightly higher levels of Calcium detergents (Ca is better than Mg or Na based detergents in a diesel) and some have high levels of Zinc that might be an issue for a petrol engine CAT.

Some B4 oils like Shell Ultra 5w40 do have a slightly different viscosity to their equivalent petrol equivalents, although that often relates to approvals or recommendations the oil has.


I don't follow, ACEA B4 was discontinued more than 10 years ago. Shell Helix Ultra 5w40 is A3/B4 rated, for petrol and diesel.

I believe the OP was referring to HDEO, i.e. ACEA Ex or API Cx. I suspect many off these lubes would work in a petrol engine but have never been evaluated or tested. Some that may not qualify could potentially still pass all the engine performance requirements are work quite well. Unless we do our own testing we will never know, that's generally why we buy oil from a trustworthy source with the specs we need on the pack.

 

[SonofJoe]

I personally wouldn't be overly bothered about running a petrol engine long-term on a diesel oil.
The only things I'd say is that true HDDO's tend to be more expensive than PCMO's and are generally only available in the heavier viscosity grades (although this is changing). So if, like me you're a miserly git who wants maximum fuel economy at minimum cost, you're better off with PCMO.

 

[Olas]

For passenger cars with catalysts/dpf/scr etc etc, E6, E7 and E9 are all suitably low saps. Only E4 Is suitable for engines without particulate filters or otherwise

E: Heavy Duty Diesel engine oils

ACEA E4 Stable, stay-in-grade oil providing excellent control of piston cleanliness, wear, soot handling and lubricant stability. It is recommended for highly rated diesel engines meeting Euro I, Euro II, Euro III, Euro IV and Euro V emission requirements and running under very severe conditions, e.g. significantly extended oil drain intervals according to the manufacturer's recommendations. It is suitable for engines without particulate filters, and for some EGR engines and some engines fitted with SCR NOx reduction systems. However, recommendations may differ between engine manufacturers so Driver Manuals and/or Dealers shall be consulted if in doubt.

ACEA E6 Stable, stay-in-grade oil providing excellent control of piston cleanliness, wear, soot handling and lubricant stability. It is recommended for highly rated diesel engines meeting Euro I, Euro II, Euro III, Euro IV, Euro V and Euro VI emission requirements and running under very severe conditions, e.g. significantly extended oil drain intervals according to the manufacturer's recommendations. It is suitable for EGR engines, with or without particulate filters, and for engines fitted with SCR NOx reduction systems. E6 quality is strongly recommended for engines fitted with particulate filters and is designed for use in combination with low sulphur diesel fuel. However, recommendations may differ between engine manufacturers so Driver Manuals and/or Dealers shall be consulted if in doubt.

ACEA E7 Stable, stay-in-grade oil providing effective control with respect to piston cleanliness and bore polishing. It further provides excellent wear control, soot handling and lubricant stability. It is recommended for highly rated diesel engines meeting Euro I, Euro II, Euro III, Euro IV and Euro V emission requirements and running under severe conditions, e.g. extended oil drain intervals according to the manufacturer's recommendations. It is suitable for engines without particulate filters, and for most EGR engines and most engines fitted with SCR NOx reduction systems. However, recommendations may differ between engine manufacturers so Driver Manuals and/or Dealers shall be consulted if in doubt.

ACEA E9 Stable, stay-in-grade oil providing effective control with respect to piston cleanliness and bore polishing. It further provides excellent wear control, soot handling and lubricant stability. It is recommended for highly rated diesel engines meeting Euro I, Euro II, Euro III, Euro IV, Euro V and Euro VI emission requirements and running under severe conditions, e.g. extended oil drain intervals according to the manufacturer's recommendations. It is suitable for engines with or without particulate filters, and for most EGR engines and for most engines fitted with SCR NOx reduction systems. E9 is strongly recommended for engines fitted with particulate filters and is designed for use in combination with low sulphur diesel fuel. However, recommendations may differ between engine manufacturers so Drivers Manuals and/or Dealers should be consulted if in doubt.

 

[chrisri]

Originally Posted By: B320i
Originally Posted By: "chrisri"
If you are referring to a single rated ACEA Ex commercial oils they are not recommended for use in petrol cars. Excessive SAPS level in some Ex specifications' can cause spark fouling, preignition, detonation and premature wear on CAT.

THAT is incredibly interesting. Am at present figuring out an issue with pinging on my vehicle (see previous post). Used Rotella T6 on a short interval, no issue. Using a BMW-approved, ACEA A3/B4 Full-SAPS oil with a strong zinc package, what you post makes me wonder if the oil *could* be causing my problem. No consumption, aside from my (almost) religious checking of the oil every week or so.


I have to correct myself; I've used oils with 1.9% ash , 1.6% would still qualify as a passenger type (A3/B4 to be specific).

As I said already, using E4 oils in a engine that does not consume oil shouldn't cause a problem. However using oils with these high ash level in a petrol car that use fair amount of oil WILL.

I have lost an engine (oil user) because of excessive chamber deposits. Using 1.9% surely accelerated formation of deposits eventually leading to a chamber hot spots and uncontrollable ignitions'.

Car was used in the city, by my wife and was sporadically pushed. Piston blew when I took the car for a spirited drive. At 7k rpm engine lost power working on 3 cylinders, after few kilometers it hydrolocked (oil in the cylinder).

Rotella should be a low SAPS HDEO, right? Using BMW approved oil couldn't cause your problems, since it is dual rated oil.

Either way, track down that detonation /preignition as you could find your self in a situation I was. Take the car out for a spirited drive every now and then, just not overly spirited as I did. Point is to try to remove deposits by creating higher temperatures, yet not to high to create hot spots.

 

[FCD]

Originally Posted By: B320i
Originally Posted By: "Shannow"
Back in the day, they were "known" to cause pre-ignition causing deposits around the perimieter of the combustion chambers.

Would this be a result of the higher levels of ash in the additive package?

Originally Posted By: "UltraFanUK"
They don't have a better add pack and it's a daft idea to use them in a petrol engine as they might have incompatible seal conditioners.

If its not better, then its just different, I suppose?

By the way, I think the member posting what you responded to was indicating more towards products like M1 TDT 5w-40, along with dual-rated diesel oils.

Not sure about seal conditions, but I think its a fair bet that different manufacturers would probably use different (substantial or not) rubber seals to meet the needs of their application. Some are more durable than others.

Concerns over catalytic converter wear are moot if the engine isn't burning oil. If a vehicle burns enough oil to damage cats, I imagine that would be the least of the owners worries...

Originally Posted By: "FordCapriDriver"
also what car do you have?

The query is just a general question, unrelated to any future oil usage decisions in my vehicle (a '93 E36 BMW), although a fair question given the usual "What oil?" threads we get.


I was thinking maybe you had an old school muscle car but on a 20 year old BMW i don't think you'd benefit from a Diesel oil at all.

 

[TiredTrucker]

The new PC11 (FA4 and CK4) will change the dynamics a little.

 

[BrocLuno]

The only true "Diesel Engine Only" oils that I know of are like Exxon/Mobil MarineGuard. They are designed for ships engines or staionary power plants. They have no place in a gasoline engine. TBN's in the 15 range, etc.

The OP said diesel engine oil, so I take it to mean these sorts of lubricants...

For dual rated oils like Rotella T6, it's a non-issue

 

[4WD]

Used many a drum of the old Mobilgard ... Still around under new names and nicer drums

 

[BobFout]

Originally Posted By: supercity
Originally Posted By: UltrafanUK

Most diesel only (Acea B4) oils have slightly higher levels of Calcium detergents (Ca is better than Mg or Na based detergents in a diesel) and some have high levels of Zinc that might be an issue for a petrol engine CAT.

Some B4 oils like Shell Ultra 5w40 do have a slightly different viscosity to their equivalent petrol equivalents, although that often relates to approvals or recommendations the oil has.


I don't follow, ACEA B4 was discontinued more than 10 years ago. Shell Helix Ultra 5w40 is A3/B4 rated, for petrol and diesel.

I believe the OP was referring to HDEO, i.e. ACEA Ex or API Cx. I suspect many off these lubes would work in a petrol engine but have never been evaluated or tested. Some that may not qualify could potentially still pass all the engine performance requirements are work quite well. Unless we do our own testing we will never know, that's generally why we buy oil from a trustworthy source with the specs we need on the pack.




Deleted.