mixing petrol oil and diesel oil ?

zxb29 · Post by **zxb29** » 17 Jul 2006, 16:27

hi all

would mixing oils cause any problems in a diesel engine ?

what i mean is topping up with petrol oil ?

406 V6 · Post by **406 V6** » 17 Jul 2006, 16:33

Just make sure the oil ratings are the ones specified to your engine. Nowadays diesel and petrol oils are very close in terms of specifications.
As longs as it meets them and the mixing proportion is kept low(in case it doesn't meet the specs), there should be no problems.

AndersDK · Post by **AndersDK** » 17 Jul 2006, 16:59

All engine oils have 2 important specifacations to watch for :
1) the viscosity grade - i.e. the 10W40, 15W40 etc. figure
2) the API spec - i.e. the SC/CF type of notation. This is a measure of the oil's durability - and in most cases directly relates to the retail price (not always true though !)

Only rarely the oil will be specified single purpose for diesel or petrol or turbo, as any recent engine oil will do for all these working conditions.
And they all mix with no problem at all. No matter if mineral, semi-synthetic or fully synthetic types.

Dave Burns · Post by **Dave Burns** » 17 Jul 2006, 18:56

The odd top up wont hurt but when you change the oil fill up with a diesel specific oil, this contains detergents and other aditives that help prevent the formation of varnish.

Dave

DaveW · Post by **DaveW** » 17 Jul 2006, 19:58

Dave Burns wrote:The odd top up wont hurt but when you change the oil fill up with a diesel specific oil, this contains detergents and other aditives that help prevent the formation of varnish.

Dave

Most oils now state that they are suitable for all engine types - e.g. ".. suited to all car petrol and diesel engines icluding those with turbochargers .."
I assumed that included anti varnish and detergent qualities as Anders suggested.
Given a suitable specification, I now use any oil that states something similar to the above.

Dave.

sub42 · Post by **sub42** » 17 Jul 2006, 20:12

Yep, I mix them on my car. Just don't do it with any new VW's! Just had a warranty claim thrown out by VW on the company fleet. Seems that VW state one type of oil, VW506.01 or something, and our driver was filling it up with GTD magnatec. Anyway, it had a lifter failure, and they tested the oil...

Bye Bye engine.....they said that it would carry no warranty on the drivetrain from here on out. I still think that they were just being pedantic

AndersDK · Post by **AndersDK** » 17 Jul 2006, 21:17

You will find that most branded oils reads on the label : conforms to VW506.01, Mercedes xxx, BMW yyy, MIL something, API lots, Ford anything etc. etc. etc. etc. ...
If you read the label closely.

The VW506.01 is not a special type of oil - but a certain minimum spec of oil. (Most likely a semisynth 10W-40) not !.

Edit : The VW506.01 spec requires a synthetic 0W-30.

3eme_attaque · Post by **3eme_attaque** » 18 Jul 2006, 00:10

it may seem pedantic to void the warranties on those new vw's but they and many new-ish german cars are designed around those wide graded or thin synthetics. it will be interesting to see what happens in a few years time when owners who can't be bothered to shell out more for the correct oil have clocked up the miles in them. i assume something similar but on a larger scale as all the fords these days that sound terrible from not using 5w30. wonder if citroen will decide to use more specific grades?... seems to be the trend..

Kowalski · Post by **Kowalski** » 18 Jul 2006, 10:52

There is a trend to the thinner oils because they make the engine marginally more economical, once one manufacturer starts doing it all of the others will have to too. I wouldn't worry about it too much, if lots of cars need thin synthetic oil it'll get cheaper and easier to get hold of, eventually you'll not be able to get anything else.

I quite like the fact that my XUD is just as happy on the cheapest engine oil as it is when its got the nicest 5w40 fully synthetic diesel engine oil. I've heard scary stories about the newer thinner oils and newer engine's ability to drink a sumpfull in rather less time than the service interval!