Oil query on greade ? garage says I'm using the wrong stuff

I've never owned a car yet that didn't have the correct grade of oil listed in the handbook. Why not have a look in there?

FWIW, my money's on the garage being right...

Chris

VW recommendations do change with the times. OPIE oils say synthetic:

... they were right which means I've been using the wrong stuff for a while :-s

Thanks for that, at least I have figured out whats needed. When I originally got the car all the service history was 10/40 semi synthetic oil used and then the specialist I used to live near used that but this place has suggested rightly other wise. I guess its been changed for some reason.

I had the car back at the garage and mechanic says if its been run on 10/40 for most of it life its probly best to stick with that otherwise you can get problems or premature wera using thinner oil ? .. he did say if I go with the newer recommendation to have an engine flush before the oil/filter change.

Is quite confusing I must say. I left them to flush it and oil/filter change it. Hopefully I made the right choice.

The main reason they recommend fully synthetic is because fully synthetic oils take longer to break down before losing their lubricity. This allows manufacturers to quote longer service intervals and lower cost of ownership, which is particularly attractive to stingy types or fleet buyers.

Fully synthetic oil has a few other advantages, such as better performance at extreme temperatures, but for normal driving in the UK I honestly don't think you will have done any harm running it on 10/40 semi synthetic, providing you have done regular oil changes. Using a cheaper oil and changing it more frequently is often just as good, if not better (since you're more frequently chucking out the contaminants that build up in the oil), than using an expensive fully synthetic oil and only changing the oil at the long intervals (eg. 20k) that manufacturers quote these days.

Doing a flush is never a bad thing and you'll probably be OK with switching to fully synthetic, but if it were me I would have stuck with 10/40 and done more regular changes.

Only because it costs 1 hour labor for an oil change and a fleet vehicle is unproductive for a day.

If it's just cash and cost of oil and fliter as it for a DIY owner then it's expensive.

I think it's done to reduce the number of oils: the range for VAG was pretty complex at one point, with different oils for petrol, diesel, longlife, normal life, PD unit injectors etc etc. Even the dealers got it wrong a lot of the time.

you have never owned an isuzu trooper then

handbook says 10/30 but if that is used car won't run properly must be 5/30

regards

It depends where you drive the vehicle (climate wise)

I've never known any car not run properly with the incorrect oil.

Most handbooks give a range of oils, depending on the local conditions. It's unlikely the same oil would suit for both the equator and north pole.

no the handbook is wrong as are the books at many of the parts suppliers eg Parkers

the handbook is also wrong in respect of where on the dipstick the oil level should be

It is to do I think with problems with the injectors which did not come to light until after the cars were sold

I always check with main agent and an owners club forum before buying oil for a vehicle that is new to me

Regards

Be interested to know how the oil grade effects the injectors.

found this on the net:

"The injection system on that vehicle relies on oil pressure to inject the fuel."

from:

maybe it is like the older sd1 where low oil pressure stops the fuel pump?

This is how the injectors work

The HEUI uses engine oil under high pressure to power the plunger rather than a fuel injection pump camshaft lobe to power the plunger. The HEUI uses engine lubrication oil that is pressurized from 870 psi (6 Mpa) to 3500 psi (24 Mpa) to pump fuel from the injector. The HEUI operates in the same way as a hydraulic cylinder to multiply the force of the high- pressure oil.

Why the actual grade of oil is critical I do not know but it is

Regards

Slightly more viscos oil probably slows the compression process down, a bit like running ep 90 and 0 35w through a small inlet valve

Would need to be a very thin oil to drop the pressure that much. It's usually a faulty oil pressure switch. Later cars used a different design.