a few questions about HDEOs

[19jacobob93]

When I people talk about HDEOs they normally mention a diesel oil and I have a few questions that need answering to help me understand!
1. First off, are all HDEOs designed for diesel engines or are some designed for gas engines and both?
2. Are all diesel oils examples of HDEOs? (Even the cheaper ones like XLD Diesel)
3. What makes HDEOs so 'heavy duty' and what do they have over regular PCMOs?
4. Do they have anything extra added to help them work harder?
5. Would I be better off running say a 15w40 HDEO over a normal conventional 15w40?

Thanks!

 

[19jacobob93]

Oh and 6. What makes diesel engines harder on oil and need a HDEO?

 

[Volv04Life]

I actually wondered this myself while at work! Its crazy! i too want answers.

 

[JR]

answer for 19jacobob93, soot a byproduct of burning the higher sulfer content of diesel fuel. also do to the higher compression and higher combustion pressures the mains and rods see higher loads. also IH and cat use heui based fuel system, extreme rigors on oil.

1) some carry diesel only and some are dual spec (gas and diesel)




-harvey will anser more when time permits.

 

[Chris142]

A diesel engine will load the oil with soot,making it black in minutes.

 

[aquariuscsm]

I read here years back that the "soot scrubbing additives* in HDEOs can be harsh and abrasive in gasoline engines. Is this myth or fact?

 

[Brigadier]

Seems to me, if it is dual certified, no.

a lot of VW, Subaru, and BMW owners run Rotella T6 5W40 which is CJ-4/SM rated with excellent results and UOAs. I run it in my Colorado.

Originally Posted By: aquariuscsm
I read here years back that the "soot scrubbing additives* in HDEOs can be harsh and abrasive in gasoline engines. Is this myth or fact?

 

[garyb80]

Originally Posted By: Brigadier
Seems to me, if it is dual certified, no.

a lot of VW, Subaru, and BMW owners run Rotella T6 5W40 which is CJ-4/SM rated with excellent results and UOAs. I run it in my Colorado.

Originally Posted By: aquariuscsm
I read here years back that the "soot scrubbing additives* in HDEOs can be harsh and abrasive in gasoline engines. Is this myth or fact?

I thought Shell no longer recommended any Rotella in gasoline engines with a catalytic converter.

 

[Brigadier]

Maybe to cover their butts in this lwayer infested world, they don't. But it is SM rated, and when my 2006 Colorado was built, all PCMO was SM rated. So for my application, I don't see an issue. I think the whole poisoning the cat with ZDDP thing a a theoretical problem that rarely ever happens. And then only if you have an engine that burns as much oil as gasoline.

Anyway, check out the VW, Audi, WRX forums. Lots of T6 being run in those cars, and I don't see them complaining about replacing cats.

https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2020450

http://www.pqiamerica.com/June 2014/shellrotellat6.htm



Originally Posted By: garyb80
Originally Posted By: Brigadier
Seems to me, if it is dual certified, no.

a lot of VW, Subaru, and BMW owners run Rotella T6 5W40 which is CJ-4/SM rated with excellent results and UOAs. I run it in my Colorado.

Originally Posted By: aquariuscsm
I read here years back that the "soot scrubbing additives* in HDEOs can be harsh and abrasive in gasoline engines. Is this myth or fact?

I thought Shell no longer recommended any Rotella in gasoline engines with a catalytic converter.

 

[jrmason]

Modern CJ oil has lower ZDDP additives to protect the DPF (diesel particulate filter). They are much more complex and expensive than any modern cat, in reality a cat will most likely rot out or plug up from normal exhaust gasses long before any additives in the oil plug it up.

Diesel oils are much more robust and have high levels of additives or TBN to neutralize the acids that build up in the crank case from the trace amounts of fuel and soot. Even in the most efficient diesel engine there is and always will be a small amount of blow by, it is a byproduct of running more than twice the compression ratio of your average gasoline engine.

 

[Brigadier]

using the Lubrizol Comparator,

Here is Dexos 1 which supersedes my Colorado's GM6094M requirement:

Here is CJ-4:

Look at 'Aftertreatment Compatibility'.

Like I said, a theoretical problem....

 

[Solarent]

Originally Posted By: 19jacobob93
When I people talk about HDEOs they normally mention a diesel oil and I have a few questions that need answering to help me understand!
1. First off, are all HDEOs designed for diesel engines or are some designed for gas engines and both?

There are mixed fleet oils which bear both the CJ-4 and SM or SN. These meet the basic requirements of both specs, but the 15W40 grade gets a pass on the 800ppm phosphorus limits.

Originally Posted By: 19jacobob93
2. Are all diesel oils examples of HDEOs? (Even the cheaper ones like XLD Diesel)

What you want to look for is the API CJ-4 specification. This is what qualifies it as a HDEO.
Originally Posted By: 19jacobob93

3. What makes HDEOs so 'heavy duty' and what do they have over regular PCMOs?

Its a completely different DI design. HDEO are designed to handle heavy loads and towing, soot agglomeration and to reduce sulfated ash which can cause issues with DPF systems.
Originally Posted By: 19jacobob93

4. Do they have anything extra added to help them work harder?

See above. Because the 15W40 grade isn't restricted to 800ppm phosporus (and Zinc usually tracks with phos levels) some people are under the impression that HDEO have a more robust additive package. I would say that a CJ-4 and SN additive package is different, like comparing apples to oranges.
Originally Posted By: 19jacobob93

5. Would I be better off running say a 15w40 HDEO over a normal conventional 15w40?

That depends a lot on your application. Odds are you aren't going to find a 15W40 that isn't a CJ-4 spec oil.