Can long life oil be mixed with normal oil?

[reggieroo]

Yesterday when driving down the motorway the oil light light came on to say I had low oil, pulled in at the services & sure enough the oil was on the minimum. I'm going to top it up but only have 10-40w semi in the garage, wondering if it would be better to top up using this before I drive it again or go get some long life oil from Audi.

I'm even thinking of giving it an oil change with fully synthetic & not using the longlife stuff soon. On my service book the last owner had only done a long life service on the last one, it hasn't had long life oil before but looking at the book he was a few thousand mile out on the last two inspection services so guess he thought a long life service would suit him better.

 

[adamss24]

Having oil in the engine is better than beeing short of it ! It's ok to top up with up to 1L of oil if needed...

 

[reggieroo]

That's pretty much what I thought but then thought I'll probably do it & somebody will say "what have you done that for, you can't mix the two oils"

 

[adamss24]

Oils do mix pretty well, do-it if you need to, even the dealer supplied manuals advice in topping up with oil regardless of spec. Some oil inside might save your engine as opposed to having none !

 

[Mazzy46]

Until I decided to have the timing belt changed (A6 2.7T year 2000), I had stuck with recommended fully synthetic oil and changed as advised by onboard computer. However, engineer horrified at state of oil and since then, I am changing every 12 months as he has recommended. Still using fully synthetic but probably move to semi-synth at next service. Only doing 6.5k miles pa but as this is in London, wear is relatively heavy for mileage.

 

[reggieroo]

I'm also wondering what oil to use when I replace it all, pretty sure fully synthetic is what I should use but not so sure it is best for an older engine as it's thinner than semi I believe.

We should all really change our oil as soon as it turns black which I'd imagine is way before a service is due.

 

[crispin]

long life only worth it if you do some long trips, I used long life on my S6 and it always said it needed a service every year as I did lots of shortish trips hence I would have been better oo using the fixed service interval. The car works it out.

 

[reggieroo]

Time for an oil change, fully or semi?

 

[adamss24]

Only use fully synthetic oil mate, either 5w30 or 5w40. I would use the thicker 5w40 if i were you however the 5w30 gives better fuel economy as it's easier to pump round the engine and also has better wear protectors to cope with extended drain intervals. Change the oil and filter every year or 6k regardless of what oil you use if you want the engine to last well !

 

[reggieroo]

I did an oil change the other day using some free 0-30w Castrol fully synthetic that I got off a friend. Since doing the oil change the engine sounds noisier, like a ticking noise that I didn't hear before.

Is this too thin for an engine that now has 133k on it?

 

[murran]

use fully synthetic.
i read an online blog by an oil expert a few years ago. he disapproved of semi-synthetic oils calling it a marketing excercise. he described it as mixing a smirnoff vodka "shot" bottle mixing it with a cheap vodka then over pricing it on sale.

0/30w is too thin really. an engine with 133k on it will have (comparativly) big gaps between the bearings/tappets etc. thinner oils will be able to get out of the gaps more easily and so the oil pressure will be less.