Club 80-90 Forums

my 1.9DG is running sweet on LPG but I reckon it sounds slightly 'noisy' since the conversion,the engine was very quiet before have been using castrol gtx 10-40 since I bought it almost four years ago and have bought some mineral oil today to do an oil change before Busfest,the oil in the engine has done about 2000 miles at the moment,have looked in the wiki and not seen anything about engine flushes,was thinking about adding some car lube engine flush to the oil before filling up with the new oil,the gtx has been no problem the engine is nice and oil tight and uses no oil between changes,the mileage is 98700 miles,oil changes every year and filter as well,do I use the engine flush or just do a normal oilchange???

I have been told that using fully synthetic quietens things down.I shall be using it myself next oil and filter change.

I've heard that engine flushes are not advised on an old engine, as they may dislodge crud from the oilways which might then cause a blockage somewhere. On another similarly old-school car of mine it used to annoy me that the fresh oil was almost immediately stained black with the remains of the old oil, so I started to do a double change. I'd buy the cheapest equivalent grade I could find, usually from the co-op but I think they've stopped selling oil, pop that oil in and run the engine for 10 minutes or so to allow it to circulate properly, then drop that oil and put the good stuff in. I can't remember whether I changed the filter before or after the cheap oil though - probably after I think. The new oil generally stayed pretty clean between changes that way.

scottbott wrote:do I use the engine flush or just do a normal oilchange???

I'd just change. It's not a particularly high mileage engine, it's not been exactly neglected. Remember - these engines were intended for use in vans. Commercial vehicles. Working hard for a living. In campers, they're pampered. Often, they do a month's mileage in a year.

Remember - the VW owner's handbook does NOT say "Use mineral only". It explicitly mentions and approves using synthetic. It also strongly advises using oil that meets VW 505.00 spec. Most mineral-based oil these days is cheap rubbish, and will NOT meet various manufacturer-approved specs.

Oh here we go again!

Synthetic is better than mineral, of that there is no doubt! however, many (not all) of our aging wasserboxers suffer from 'tappet bleed down' (usually after a few days parked up when the engine was turned off hot after a longish journey)
Thinner oils (10w40/5w40/5W30) exacerbate this tendancy.......

So my objection is not against synthetic oils, just the thinner viscosities that these oils tend to come in. Castrol do a Semi Synthetic 15W 40...that would be my choice, however regular oil changes of even a basic oil are better than less frequent changes done with a better brand...IMO.
However, as there is little or no damage caused by the 'bleed down' you could always try the fully synthetic and if it suits your engine and doesn't cause regular cold start rattles then job done. If on the other hand the loud tappet noises appear every couple of weeks revert back ...simplez.

I love the way Adrian quotes VW specs as if by waving a manual at your engine and saying out loud (stop rattling, VW say this oil is fine!) will make the noise go away. lol.

PS. tappet 'bleed down' is by no means down to just the age and mileage of our engines....as I remember a high number of petrol engine Transporters would regularly need a good thrashing on PDI (pre-delivery inspection) to get rid of this 'death' rattle....(I worked at a main VAG garage in the mid 80's).....back then 15W40 quantum 'Blue' was the recommended oil in the UK....although the booklet allowed for many variants depending on ambient temps/working range.

Martin

California Dreamin wrote:So my objection is not against synthetic oils, just the thinner viscosities that these oils tend to come in.

I don't think anybody has ever suggested varying the viscosity from those recommended, and certainly not purely because of a different base. I know there has frequently been great confusion and failure to separate the two concepts in the past, predominately from the "Mineral on pain of death!" corner.

I'm still unconvinced about tappet bleed-down being related to the cold oil viscosity - not that rattly tappets are anything much more than a mild annoyance anyway - and would have thought maintaining hot oil pressure would be a greater contributory factor to oil choice on a slightly tired engine.

AdrianC wrote:

California Dreamin wrote:So my objection is not against synthetic oils, just the thinner viscosities that these oils tend to come in.

I'm still unconvinced about tappet bleed-down being related to the cold oil viscosity - not that rattly tappets are anything much more than a mild annoyance anyway

The first point.....I guess having never experienced this phenomenon? it's easy to be so adamant about your opinion.
Second point.....I agree but if you had of experienced bleed down then you'll know it can sometimes take 20 - 25 minutes of hard driving to purge the air in the offending tappet and in the meantime it is extremely embarrassing when stuck in traffic.

Martin

California Dreamin wrote:I guess having never experienced this phenomenon?

I have - our 200k mile DJ rattles for a while (worst has been 5-10 miles) after it's been sat a month or so. IIRC it's currently on off-ish brand 5w40 full synth that's probably overdue for a change. The hydraulic tappets in my ol' Saab used to do it for a minute or two after being left overnight, but only as the oil got about due for changing.

it's easy to be so adamant about your opinion.

I didn't say I was "adamant". I said I was "unconvinced". Very different.

if its black and slippy pour it in

i would never put the cleaner stuff in for fear of dislodging something or causing the end of the world.. But i do use a expensive oil with detergents in it (like shell helix) and use quality fuels on the majority of fills. The detergents in both these are pretty mild and will gradually clean the engine. But the daily drive gets crap fuel and oil and never breaks down, hhmm...

So, now that these engines are even older and more worn out ( in many cases) than when 15/40 was specified.
Would I be Ok just putting cheap branded 20/50 mineral oil in my petrol engined version ?
Bearing in mind that it gets through a usual amount.

vanisveryrusty wrote:Would I be Ok just putting cheap branded 20/50 mineral oil in my petrol engined version ?

I wouldn't put that rubbish in anything that I wasn't planning on scrapping in a year or two, tbh. It's not as if there's a big cost saving over decent stuff, either.

Bearing in mind that it gets through a usual amount.

<scratches head>
Define "a usual amount"...

Oil join in.....

Interesting info on this subject here: http://www.ratwell.com/technical/OilSel ... synthetics" onclick="window.open(this.href);return false; - interesting not least 'cos of the properties being lost in modern Synthetics due to prolonging the life of catalysers and reducing polution... properties that prevent wear, eek!

Perhaps the best of both worlds is a synthetic around 15w/50, along with an additive (i.e. Lucas Additive) that helps the oil to cling to metal surfaces when the whirly bits aren't whirling. I tried Lucas with the last (mineral) oil change, which made a huge difference to tappety start-ups, will be going synthetic and additive next time.

AdrianC wrote:

vanisveryrusty wrote:Would I be Ok just putting cheap branded 20/50 mineral oil in my petrol engined version ?

I wouldn't put that rubbish in anything that I wasn't planning on scrapping in a year or two, tbh. It's not as if there's a big cost saving over decent stuff, either.

Bearing in mind that it gets through a usual amount.

<scratches head>
Define "a usual amount"...

Is there really a difference between cheap oil and expensive oil ?
It all meets the same industry standards.
"usual amount", not measured it yet. Just what I would expect for an old car running an engine that may be the original.
I usually find its frequency of oil change rather than quality of oil used which prolongs the life of engines.

vanisveryrusty wrote:Is there really a difference between cheap oil and expensive oil ?
It all meets the same industry standards.

Not quite that simple. After all, cheap Chinese concrete-teflon tyres "meet the same industry standards" as Michelins etc...

There's the API rating (SF/CD or whatever).
There's various manufacturer ratings (VW 505.00 etc).
There's viscosity (15w40 etc).
There's base stock (mineral/semi-synth/full-synth).

And that's all for fairly normal oil. Get into performance stuff, and there's a whole new world of reasons for the price to soar.

Yes, older engines like our vans are much simpler to pair oil with than modern higher-tech, more pernickerty engines. Stuff supermarket 20w50 into a modern 16v common rail turbo diesel, and you're looking at all sorts of expensive repairs before too long. All the wrong stuff will do for us is increase internal wear a bit. But if you want your engine and van to live as long a time as possible rather than lob it after a couple of years, that's fairly important.

Yep, various modern oils are low ash for DPFs, EGRs and the rest of the modern alphabetti spaghetti toys, sure. But that's all covered in the API ratings - and I suspect that those will be far too thin for our engines anyway.

That was interesting Adrian, thanks.
Should I use a decent 20/50 then ?
As opposed to a cheapo one.