Mixing engine oils....?

[pimpdriver]

Ok, got my oil changed on the 80tdi 3 months ago.

They used Total 10W40 semI synthetic.

Diesels can use oil between changes (allowable amount in the handbook).

Is it ok to top up with some other brand (same 10W40) or do I have to use the same type???

[Emjay]

stick to the same type. Different oils have different properties according to type and temperature. It's quite complicated but to get the best out of your engine use the correct oil and dont blend.

You wouldn't think about running on a mix of snow tyres and summer ones at the same time now would you?....would you??!

[John.]

If it's 10/40 semi synth you're adding it'll make no difference. If it's ordinary mineral oil then you'll be degrading the oil a very small amount. As the oil's been in for more than 2 minutes it'll be as black as the hell of hells anyway. Topping up with a lesser grade of oil is better than not topping up at all
John.

[pimpdriver]

I want to add Quantum 10W40 semi to Total 10W40 semi.

[rich.r]

Originally Posted by John.

If it's 10/40 semi synth you're adding it'll make no difference. If it's ordinary mineral oil then you'll be degrading the oil a very small amount. As the oil's been in for more than 2 minutes it'll be as black as the hell of hells anyway. Topping up with a lesser grade of oil is better than not topping up at all
John.

i agree
if its a semi with a semi the blend will be near as dam it the same

all oils have to be produced to a certain standard and this can be checked on the tin

i have been told the very expensive oils have extra additives but all will blend
even a mineral will blend with a semi as a semi is basically a mineral oil anyway

h t h

[yeti]

I was always told that for a minor top up, anything's fine, except mineral or part synth into fully synth, so I can't see any issue there.

Personally, I don't believe a basic diesel like an 80 should use a noticable amount of oil. My (ford)van doesn't, and it's just hit 170k.

[type81]

Go for it. as the garage has used total 10w40 semi which can be used in petrol or diesel
vehicles instead of a predominatley diesel engined oil.....it shouldnt have a negative effect.

[type81]

Originally Posted by yeti

I was always told that for a minor top up, anything's fine, except mineral or part synth into fully synth, so I can't see any issue there.

Personally, I don't believe a basic diesel like an 80 should use a noticable amount of oil. My (ford)van doesn't, and it's just hit 170k.

most probley coz the Audi 80 Diesel has the turbo......non turbo less oil consumption?

[20vcqdriver]

If you were running a high power modern TDi like the latest V6, then it might become important, but for a low stress old 80TDi a top up of any similar semi of the same grade will be fine.

[pimpdriver]

Originally Posted by yeti

I was always told that for a minor top up, anything's fine, except mineral or part synth into fully synth, so I can't see any issue there.

Personally, I don't believe a basic diesel like an 80 should use a noticable amount of oil. My (ford)van doesn't, and it's just hit 170k.

The 80 has used 0.5 litre in 3000 miles which is well in spec.

Our A4 used to do the same.

The 80TDI (1Z) engine was really advanced for its time!

Just needs some tweaks to get 140bhp (TDIClub.com here we come!)