Petrol engine spec'ed for 5W40 convert to 5W30 C4?

[Superflan]

Hi folks,
I read bitog everyday, and now I'm joining in to get some peaceful advice

One oil to rule them all : should I switch my Renault Clio MkIV, 1.2 L4 16v NA Gasoline engine (D4F740, 55kW@5500rpm, 105Nm@4250rpm), spec'ed for 30000Km OCI on 5W40 (ACEA A3) to 5W30 (ACEA C4 level C3) RN0720 oil ? Daily rpm range : 2000-3500rpm, trashing it to the redline once a gas fill-up. Average fuel cons. : 6.5L/100km.

The reason behind this : my wife drives a Renault Koleos, powered by a M9R commonrail turbodiesel engine, running on 5W30 RN0720 (ACEA C4) DPF low-saps oil... got a relatively big sump (7 liters) and changes oil every 6 months (15000Km), so I got good deals on 5W30 C4 oils (Q8 Formula R Long Life, Yacco Lube R, Repsol Elite Evolution Power 4) as long as I buy min. 24 liters at once.

So, I was thinking of reducing oils kept on the shelf at home (5W40 for one car, 5W30 DPF for another, 10W30 for the Honda CB500X and NSR 125 gearbox, the power generator, and the lawnmower, Dexron III (Q8 Auto15 ATF) as fork oil, Nissan NS-II (Q8 Auto CVT-PB, still haven't done an oil change) for the Koleos' CVT, Tecnol Bioracing 2 stroke sunflower oil for all the 2 stroke stuff (NSR, chainsaw, 4-mix grass trimmer, mistblower, small 2-stroke generator...)

tl;dr : would switching my 5W40 spec'ed petrol engine to 5W30 full syn C4 diesel oil be benefic for that engine, or should I stay to the original 5W40 full syn A3/B4 spec ?

 

[Quattro Pete]

Originally Posted By: Superflan

tl;dr : would switching my 5W40 spec'ed petrol engine to 5W30 full syn C4 diesel oil be benefic for that engine, or should I stay to the original 5W40 full syn A3/B4 spec ?

Just in case you missed this earlier thread on a similar subject...

http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3558617/ACEA_A3/B4_vs_ACEA_C3#Post3558617

 

[Superflan]

Originally Posted By: Quattro Pete
Just in case you missed this earlier thread on a similar subject...

Thanks ! It was worth the read. So, basically, it wouldn't do harm to convert my gasoline engine to C4 if the fuel is low-sulphur and I am strict on OCI ? The local spec is 20000Km/1year, where France spec is 30000Km/1year (for the diesel engine Koleos, local spec is 15000Km/1year, France spec is 30000Km/2years).

Fuel here is unleaded RON 95, MON 85 Euro V / Euro VI from Singapore, sulphur less than 10ppm.

 

[Superflan]

Some C4 level C3 RN0720 oils are also spec'ed A5/B5 :

Q8 Formula R Long Life 5W-30 PDF TDS

 

[Quattro Pete]

Originally Posted By: Superflan
Some C4 level C3 RN0720 oils are also spec'ed A5/B5 :

Q8 Formula R Long Life 5W-30 PDF TDS

I don't see how they can claim both C4 and A5/B5 for the same oil. The two specs are practically mutually exclusive on the basis of HT/HS viscosity requirement.

 

[Superflan]

Originally Posted By: Quattro Pete
I don't see how they can claim both C4 and A5/B5 for the same oil. The two specs are practically mutually exclusive on the basis of HT/HS viscosity requirement.

OMG that's quite a good mystery. Submitted to the local reseller.

 

[weasley]

Originally Posted By: Superflan
Some C4 level C3 RN0720 oils are also spec'ed A5/B5 :

Q8 Formula R Long Life 5W-30 PDF TDS


It looks like that PDF is dated Jan 2009 - ACEA updated their specs in 2010 to prevent claiming A/B and C specs together.

 

[Superflan]

Got an update from Q8 :

Quote:
Ludovic,

Technically it could be correct if it’s exactly 3.5 as for A5/B5 the HTHS should be ≤3.5 and for C4 ≥3.5.

But you are correct, those two shouldn’t be on the PDS of the Q8 Formula R Long Life 5W-30 together.

The English version was already correct, and I’ve made the correction to the French and Dutch PDS too.

Regards,


David De Mesmaeker
| Product Application Engineer | Kuwait Petroleum (Belgium) N.V. |
| Product Applications – Lubricants | -----

 

[Quattro Pete]

So what is the HT/HS viscosity of this oil? He could have just stated it and put the whole thing to rest. I'm guessing it's below 3.5 cP.

 

[Superflan]

Update:

Me:
Quote:
Thanks for your input. Would you mind telling me HTHS for Q8 Formula R Long Life 5W-30 and Q8 Formula Excel 5W-40 ?

David:
Quote:
Both are ≥3.5.

Me:
Quote:
How much exactly ?

David:
Quote:
I do not have exact data. Why do you want to know?

Me:
Quote:
I’m a lubricant enthusiast, using various Q8 products since 2009 and want to push further discussing oils on BITOG (www.bobistheoilguy.com). HTHS is a recurrent discussed characteristic there.

David:
Quote:
HTHS is indeed very important as it not only has to do with fuel economy but also protection against wear.

You could use a 3.5mPa.s product in an engine that is developed for 2.9mPa.s; it will protect the engine better but will lose the fuel economy.

Vice versa is NOT possible, man should never use a low 2.9mPa.s product in an engine that is developed for 3.5mPa.s as your oil film will not be enough to protect against wear.

The exact HTHS values are not that relevant; as long as you know in which category the lubricant falls, [>2.6 & div>