High-Mileage V8 Diesel - 5W30 or 5W40?

[Bellow]

I was just making two general points, and I think they are both valid; not least, that MB include numerous 5W40 oils in their approved list.

Specifically, however, if my engine has reached the mileage it has, and uses a litre every 2000 miles, presumably mostly on MB's own oil and almost certainly on 5W30, then despite what Stephenson says, somebody has been doing something right, and 5W30 is plainly perfectly OK, so I see no need to change it; don't fix what ain't broken...

This is commonplace. The norm becomes accepted as the best achievable.
My Nissan ran hard, was not using any oil between oil changes (extended from 6000 to 9000 mile interval) when it was written off at 118,000 miles.
Everyone accepted that the smart M160 engine will require a rebuild to replace rubbish oil control rings at circa 50,000 miles. Mine went to 75,000 miles before needing to be rebuilt. Both on mineral LE8800 where fully synthetic was considered essential for the smart (and Mobil 1 was talked of in terms that implied it was handed down directly from God). Strangely (perhaps) Mercedes agreed to this and were prepared to honour the warranty (as did Nissan). They (Nissan and MB)even put said oil in during their first ever services at 6000 miles.
I've seen the photographs of the Mobil 1 engines being rebuilt and the mess and sludge was disgusting. At a mileage 50% higher, the internals of mine were spotlessly clean with nothing more than the mildest discolouration of the alloy.

 

[E55BOF]

That's an interesting point. When I topped up the oil a few days ago, the (admittedly limited) section of the top end I could see through the filler orifice looked utterly unmarked - no brown varnish stains, no sludge, absolutely nothing.

 

[Bellow]

That's an interesting point. When I topped up the oil a few days ago, the (admittedly limited) section of the top end I could see through the filler orifice looked utterly unmarked - no brown varnish stains, no sludge, absolutely nothing.

This is where it gets tricky.
The LE oils are designed as long life oils (where the recommended drain interval is extended if the oil analysis says it is prudent to do so). When an engine oil is drained, very probably the base oil is still usable but one or more of the additive packages have depleted. A long life oil therefore must have additive packages in sufficient quantity (and quality) to go the distance. This means a high degree of detergency.

From the TS article: '' If the engine started life with Break-in oil and then went to actual diesel oil with the correct ACEA “E9” or API “CK-4” approval, you would not have nearly as many check engine lights. ''

The above describes how I have used this oil (smart and Nissan) - from first service. This is the 'market' LE lubricants are made for - protecting equipment from day one. Their products are for preventative maintenance, not remedial. Understandably there is a reluctance to deviate from the OEM recommendations when the oil doesn't have the MB 22x,xx number (though I did) and jeopardise ( jeopardise - not invalidate) the warranty.

Using these lubricants (especially the engine oils) in engines with significant mileages poses the problem of the engine first seeing detergent in robust quantity and capability. The detergents will start to attack any carbon/varnish/sludge built up and mobilise it. It has to go somewhere and if is there in significant quantity the oil cannot be expected to retain all of it - so where does it go? There is no concrete answer to that but xx years and xxx,000 miles of dirt is on the march with nowhere particular to go.

Given the above, and without knowing the internals of your engine are clean enough for this not to happen, I don't think an LE oil is the correct choice here.
The drum of LE8130 I mentioned that was delivered here is for a recently acquired car with only 40,000 miles on it and dual fuel, ie, it will have run a significant amount of those miles on LPG which is very kind re keeping oil clean. And, due to a bit of remedial work I will be doing, I will have the sump lowered enough to get a glimpse of the condition of inside it. This is as daring as I am prepared to be in installing this oil in a 'used' engine.

I note your point re cleanliness beneath the filler cap on your engine but what lurks in the sump and elsewhere is unknown (I am genuinely shocked when I see the sludging present on so many engines - just does not happen with LE used from new). Setting free years of built up deposits is not trivial.

I do apologise for having to say all of this and more so for not considering it earlier. For your application (with cleanliness of inlet tract being a priority), my thoughts are that you should pursue obtaining an oil you have confidence in and consider a catch tank/separator for the crankcase breathing system. The EGR will still be present in the inlet manifold but at least the aggravating oil vapours can be excluded. I think this is a viable way forward for you.

 

[Gazwould]

Choose a LongLife oil every time and use yearly /10k .

Superior additive package with increased concentration of detergents and dispersants to keep the engine clean especially where an egr is concerned putting soot in the engine oil .

Plus some contain higher group oil basestocks , proper lab produced synthetics that allow the higher detergency to be dissolved in to them and higher thermal capability against breakdown of oil film strength HTHS .

 

[ullwn]

...... [SNIP}......

For your application (with cleanliness of inlet tract being a priority), my thoughts are that you should pursue obtaining an oil you have confidence in and consider a catch tank/separator for the crankcase breathing system. The EGR will still be present in the inlet manifold but at least the aggravating oil vapours can be excluded. I think this is a viable way forward for you.

To repeat myself from a previous posting;

"The major oil issue is ash content, high ash oil will clog the DPF.

If you physically remove the DPF and delete in the ECU, you can used oil's that are much better for a diesel engine.

On the "sludging up the inlet tracts", this is due to sending exhaust gas {EGR system] back into the intake along with the crank case pressure venting into the turbocharger, both not good for any engine.

Installing a catch can / oil separator system will be beneficial in reducing the "sludging up the inlet tracts".

If interested review the MANN + HUMMEL ProVent System"

https://oe-products.mann-hummel.com/fileadmin/user_upload/kataloge/kataloge-wartungsanleitungen-mann+hummel/kurbelgehauseentlueftung/ProVent_en.pdf

Regards

Joseph

 

[alabbasi]

A liter every 1000 mils on a diesel is not bad, top it up when needed and change it every 3000 miles.

 

[Gazwould]

Low ash C3 etc oil is reduced levels of anti wear ZDDP
( Zinc and Phosphorus ) to compensate for this the additive package concentration goes up inc friction modifiers .

As before also in some low ash oils so does the oil basestocks too .

With Mercedes spec oils their is no extra anti wear advantage of petrol , non dpf oil to dpf low ash oil .
Same anti wear performance level .

The only difference from 229.5 to 229.51 , 229.52 , 229.71 ( probably a 0W20 ) is the piston deposits and fuel economy improve .
And obviously 0 low ash performance regarding dpf with the petrol 229.5 spec .

However this isn't the case for all manufacturer spec oils and why I don't use a Merc spec .

 

[Bellow]

If you physically remove the DPF and delete in the ECU, you can used oil's that are much better for a diesel engine.

This is not a viable option in the UK.

 

[Bellow]

A liter every 1000 mils on a diesel is not bad, top it up when needed and change it every 3000 miles.

With Buddy Holly playing on the push-button Motorola.

 

[clk320x]

Low ash C3 etc oil is reduced levels of anti wear ZDDP
( Zinc and Phosphorus ) to compensate for this the additive package concentration goes up inc friction modifiers .

As before also in some low ash oils so does the oil basestocks too .

With Mercedes spec oils their is no extra anti wear advantage of petrol , non dpf oil to dpf low ash oil .
Same anti wear performance level .

The only difference from 229.5 to 229.51 , 229.52 , 229.71 ( probably a 0W20 ) is the piston deposits and fuel economy improve .
And obviously 0 low ash performance regarding dpf with the petrol 229.5 spec .

However this isn't the case for all manufacturer spec oils and why I don't use a Merc spec .

Is this oil better than 229.51 sold at MB dealers?
https://www.amazon.co.uk/Castrol-15668E-EDGE-5W-30-Engine/dp/B011KRAGH8/ref=sr_1_21_sspa?keywords=229.51+oil&qid=1580573512&sr=8-21-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzOTNYNEo2MU0xM0dLJmVuY3J5cHRlZElkPUEwNDQ0NTExMkEyMkNDVVVBSlFaWCZlbmNyeXB0ZWRBZElkPUEwNTg1NjMyMlZKRzcwR0w2OUVPUyZ3aWRnZXROYW1lPXNwX210ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

Product Specifications: SAE 5W-30; ACEA C3; MB-Approval 229.31/ 229.51; Porsche C30; VW 504 00/ 507 00

£60/8L where as it’s £60/20L of 229.51 from MB

 

[Gazwould]

Yes because it is also VW 507.00 .

But there's a better value 229.51 recommendation & 507.00 approved oil owned by VW and made by Fuchs that's available in 5L for £26 .

If you go non approved 507.00 which out performs 229.51 anyway for wear and kinder to dpf , the price is keener again .

 

[E55BOF]

A liter every 1000 mils on a diesel is not bad, top it up when needed and change it every 3000 miles.

A litre every 2000 miles is better, and that's what I'm getting; see my post #35.

Yes because it is also VW 507.00 .

But there's a better value 229.51 recommendation & 507.00 approved oil owned by VW and made by Fuchs that's available in 5L for £26 .

If you go non approved 507.00 which out performs 229.51 anyway for wear and kinder to dpf, the price is keener again .

See my post #8; that Mannol oil, according to the container, meets: API SN/SM/CF, ACEA C3, A4/B4, MB 229.31/226.5, VW502.00/505.01, BMW Longlife-04, Porsche A40, Ford WSS-M2C917A, GM Dexos2, Renault RN0700/BN/0710. The manufacturers' blurb on the container states: "Synthetic engine oil for modern diesel engines meeting the Euro 4 and Euro 5 norms (my italics; goodness knows what, if anything significant, it means).

There is no mention of 229.51 at all, yet it is in the 2019 MB Approved low SPAsh list as meeting 229.51. Old stock, so old specification? Mistake/confusion/ cockup?

I'll use if for topping up, but not otherwise.

I'm glad I started this this thread; I never realised diesel oils were so complicated, but I do now, and I certainly won't be using Mobil One at the next oil change.

BTW, I checked the DPF ash contents yesterday; 1% and 7%. I don't think that's changed in the 2000 miles since I got the car.

 

[clk320x]

Dennis with your driving style you shouldn’t need to worry about the DPF clogging up I’m sure there’s plenty of suitable speed driving where it can regenerate

 

[Gazwould]

I have never seen so much misunderstanding in anything in life as engine oil !

 

[E55BOF]

Dennis with your driving style you shouldn’t need to worry about the DPF clogging up I’m sure there’s plenty of suitable speed driving where it can regenerate

No, I'm sensible now, honest...

 

[E55BOF]

Thank you one and all; your inputs have mostly been very helpful. To sum up, then:

The engine has done 157k miles, almost certainly using 5w30 for most of its mileage. It uses one litre of oil in 2000 miles, motorway cruising at 2,200 rpm, whereas MB quote a maximum of 0.8 litres/1000 km, which would be about 2.5 litres in 2000 miles. I don’t think I have anything to worry about there.

The notional fuel consumption for the car is 26.2 mpg (I’m using the Honest John Real World figure; my MB handbook doesn’t give it), and motorway cruising at 80-85 it does 25-26 mpg. I don’t think I have too much to worry about there either.

The problem with the OM629 is that the underbonnet space is so full of engine, if the inlet tracts, turbos or DPFs need work, the engine has to come out. It’s not particularly difficult to do, but it is time-consuming and hence expensive (very…).

The DPF ash reservoir contents are pretty low; 1% and 7%, and haven’t risen in 1000 miles. If that rate of fill continues the car will be long gone before they need attention. They don’t empty themselves, and I’m sure they wouldn’t be so empty after 157k miles, so plainly they must have been done not too long ago. It is reasonable to assume that when the engine came out to do the job, the inlet tracts would have received any necessary attention at the same time.

The imbalance in DPF ash contents is odd, but not at present worrying (possibly because I don’t know enough about diesels to be worried; should I be?). If that imbalance becomes greater, I’d need to look into it.

An oil separator setup on the crankcase breather side is not, I think, a realistic possibility; even with custom pipework made up there’s nowhere convenient to put it. Maybe a bonnet bulge? On an ML? No; I don’t think so either… Besides, the engine might well have to come out to fit it; the object of fitting it would be to avoid the engine having to come out…

I think I’ve reached a conclusion (of sorts). For as long as I keep the car, I’ll carry on using 5w30, a low-ash diesel-specific fully-synthetic with the lowest NOACK value I can find, minimum spec VW 507.00 (It sounds as though I won't find a suitable CK-4/E9 spec oil). The oil will be changed annually regardless of mileage, which is very unlikely to exceed 7000 miles anyway.

Is there a better specification than the VW507.00 that I might look for, and should I look for a polyalfaolefin or a synthetic ester oil? Even better, does anyone have any specific oils to suggest?

 

[Gazwould]

Hoping the penny will drop for some..

Well 507.00 is alleged to have
polyalfaolefin and Ester both real synthetics , groups 4 and 5 respectively .

This is to compensate for the reduced ZDDP to meet low ash C3 , along with it's higher additive package concentration and being a LongLife oil it actually exceeds the previous 502.00 505.01 oil in oil performance peramiters .

It's a very available , great value , high quality both dual petrol and low ash diesel specs universal oil and the staple diet of most VAG from 3 cylinders to RS monsters , and I use it...

 

[MercedesDriver]

Hoping the penny will drop for some..

Well 507.00 is alleged to have
polyalfaolefin and Ester both real synthetics , groups 4 and 5 respectively.

Now we just have to determine which engine oil is with pure base 5,4 or 3 and which ones are diluted with group 2.

 

[Gazwould]

Most will be group 3 , a severely hydrocracked mineral ( technically synthetic accordingly to a North American lawsuit decision ) + additive package.

This precise information is hard to obtain and isn't disclosed in oil product pdf data sheets .

 

[Bellow]

Oil analysis at 86,000 miles after covering 9600 miles - with the advice being it can continue for the same again.
I spoke to the lab and they are happy with very low wear metals. The very slightly high Fe(iron) and Mo (molybdenum) are from continued bedding in of the rings and bores as the engine had new rings and bores honed 10,600 miles earlier.
All the additive packages are fine also.
This engine produces its 60hp from 700cc and with such little power is worked hard. The recommended drain interval is 9000 miles but many change at 6000 miles which is the recommended interval for the slightly more powerful (76hp) Brabus version.
While I could continue with this oil, I am going to change it as the viscosities (at 40 and 100C) have fallen. This 'shearing down' is probably a result of being worked hard though there is the outside possibility of fuel contamination but as fuel contamination was well within limits, shearing down is the likely explanation. So changing it seems prudent. On the other hand, those values could have risen - which would indicate oxidation and/or soot contamination.
My point here is I can make the decision to change the oil based on the analysis results. Changing oil every 3000 miles without a clue what the oil is like? Nah, there's better.
The real test of an oil is how it performs in service. There's the proof that my methods work. A mineral oil where MB recommend a fully synthetic with MB229.5 approval. Anyone else care to subject their oil to this level of scrutiny?

Apologies for duplicated files - only one need be opened.