Best oil for a high mileage old tech derv?

aston

The Torque Meister
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VOLVO and VW
Which oil would you recommend for a 2.1 turbo diesel Citroen 1995 with 172k on the clock? I read somewhee that mineral oils are better than synthetic oils in diesels, Any ideas? Thanks
 

HDi fun

TC ModFather
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Which oil would you recommend for a 2.1 turbo diesel Citroen 1995 with 172k on the clock? I read somewhee that mineral oils are better than synthetic oils in diesels, Any ideas? Thanks

Mineral will never be better than synthetic - no exceptions. Especially with diesels - the mineral oils do fall out of grade very soon after an oil change.

Don't flush with any solvents though. Detergents are fine. Millers Oil Flush is ideal.

I'd fill it with a decent 5w/40 FULLY synthetic oil ASAP.
 

aston

The Torque Meister
Points
302
Location
South Dorset
Car
VOLVO and VW
Something I found on the interweb about diesel engine oil.............

Engine oil is perhaps the most important component of a combustion engine, it provides separation of moving metal parts preventing seizure slowing the wear of components. Engine oil also cools the engine components including (were fitted) the turbo charger.
Engine oil options are endless, from single grade mineral oils to today's full synthetic 'race grade' oils from an equally endless number of brands with a confusing number of classifications.
Diesel engines of yesteryear were not too fussy on what oil was used, as long as it was for diesel applications it would generally provide protection, even if the oil change periods were ignored.
The modern diesel (generally 1998 onwards) however, must use the correct oil, of the correct class and be changed at the correct intervals.
Grades of oil refer to its viscosity (thickness), the lower the grade the thinner the oil. We don't have the space to explain the grade system in depth but this would easily be found on the internet.
Personally we prefer to use (were possible) an engine oil with 'body', such as 10/40, 15/40 or 15/50 as our own in house tests have shown that an engine running such oils will outlast an engine running more modern oils such as 5/30.
Unfortunately higher viscosity grade oils are simply not useable in very modern diesels, the reason for this is down to the design of modern engines.
Modern engines use very small oil galleries which a high viscosity oil would not pass through quickly enough. The modern engine is also running hotter meaning older type oils would effectively 'cook' if used.
One sometimes wonders if vehicle manufacturers have purposely designed there engines to run exclusively on these thin 'watery' oils to ensure the engines don't last too long. Diesels that ran with older style oils would easily rack up mileages of over 300k without any major engine rebuild work needed, today we see modern diesels covering not much more over 100k before a compression issue develops or some expensive to fix 'tap' appears.
Another problem would be encountered with diesel engines that utilise a DPF (Diesel particulate Filter) in the exhaust system.
The DPF is highly sensitive to the gases / particles that pass through it, use of incorrect oil would contaminate the DPF rendering it unusable to the point of blocking it.
Diesels with a DPF system MUST use correct grade and class of oil, as a rule this is a 5/30 full synthetic high performance with low SAPS and a classification of ACEA C4, ACEA C1.
Ensure you check your vehicle handbook before ordering engine oil, the wrong oil could very easily lead to a big repair bill.
Leading from engine oils it is worth mentioning oil filters, air filter and fuel filters.
With the massive greed driven motor factors battling to provide the lowest prices the supply of cheaper but inferior filters has become common.
Poor quality filters fail to trap harmful particles which cause accelerated wear of components, this leads to expensive damage.
In the past 3 years we have had multiple case of fuel system damage caused by use of non genuine 'mickey mouse' fuel filters, these cases where often related to Ford TDCI vehicles.
We strongly advise the use of original, branded filters and also advise they are purchased from a main dealer. Yes they are a little more expensive but the piece of mind they provide truly is priceless.
 

HDi fun

TC ModFather
Points
637
Location
Buckinghamshire UK
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Passat 2.0 TDi
No car maker engineers its engines to fail. Nor do they engineer the oil specs to force the engines to fail.

This would completely sod up the resale value of their cars, thereby reducing the attraction of either same brand trade-ins at best. At worst it would cause a defection away from the brand.

It's not to say that some makers aren't far less skillful than others in engineering cars for the long term ownership prospect. Some cars are poorly engineered, full stop.

I'm sticking to my guns rigidly and suggest a full synthetic oil but do a detergent flush first.

Avoid the solvent type flushes (wynns, STP etc) - these can be problematical at times, though some drivers get good results, nevertheless.

Alternatively, if you are wary, then swap the oil for a mineral one as a flush, drive a week or so and then refill with a fully synthetic, not a part synthetic - most of these are labelled semi-synthetic - they only have to contain 2% synthetic base stocks to be labelled as such.

What is the source for your post. I'll hazard a guess, without prejudice, it sounds like dieselbob.


The real raison-d'etre for synthetics is the stability of the base stocks. There is little need for VI improvers. The deteregency packs will be the same but will do less harm to the base oil, which, because of it's suitability for purpose will not degrade anywhere near as quickly as a by-product of dear ole Mother Earth.
 
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aston

The Torque Meister
Points
302
Location
South Dorset
Car
VOLVO and VW
Ha ha it was copied from the diesel bob site, if the guy is taking engines apart all day I am sure he knows what he is talking about generally
, I have purchased some Forte snake oil, both engine flush and also fuel additive and shall look out for some synthetic oil and some quality filters. I haven’t even drove the car yet as I am waiting until the end of the month to tax it. On Monday I filled up unleaded for 27.9ppl today 4 days later the same tesco’s garage is 31.9ppl…mad
 

HDi fun

TC ModFather
Points
637
Location
Buckinghamshire UK
Car
Passat 2.0 TDi
Ha ha it was copied from the diesel bob site, if the guy is taking engines apart all day I am sure he knows what he is talking about generally
, I have purchased some Forte snake oil, both engine flush and also fuel additive and shall look out for some synthetic oil and some quality filters. I haven’t even drove the car yet as I am waiting until the end of the month to tax it. On Monday I filled up unleaded for 27.9ppl today 4 days later the same tesco’s garage is 31.9ppl…mad

I'm not sure at all about DB. He recommended I use a semi in my 406 despite the fact that it's forbidden by Peugeot. It has (had to have) to have a low sulphated ash oil in order not to poison the DPF.

There are quite a few derv 'specialists' around who are stuck in the 1980s. And if they're all so good why are they rebuilding engines which they've been responsible for servicing for years?

The Forte diesel additive is good, don;'t overdo the engine flush though it is a lot harsher than Miller's engine flush. Perhaps save to Forte for the next change. And get a bottle of Millers stuff for this change.

Opieoils will sort you out with a decent synthetic for your car. OILMAN is on Torque Cars so you'll get a discount as well.
 
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