It's oil change time, and I have bought Mobil 1 5w30 ESP 507 spec for my A3 2.0TDI.

The oil that's already in the car is filthy, despite only having been in there for 8k.

I also have 5 litres of fresh oil (5w30) that was destined for my Ford Focus before I sold it.

My question is, would it make sense to drain the old oil, put the Ford spec oil in for a day or two to dilute the crud thats left, then drain that, change the filter, and put the Mobil 1 507 in?

I'm planing on extracting the oil from the top, so may leave some in the sump. Would the wrong spec ford oil cause any problems if left in the engine in small quantity?

i just think it's better to have some wrong spec clean oil, than some right spec filthy oil.

Wondering about your thoughts on this....

 

 

 

 

Keith.

A diesel engine will turn oil black very rapidly so don't place too much reliance on the colour. Having said that, if you want to use the Ford product as a flushing oil before changing to the right spec. I doubt it would do any harm.

More concerning to me is your plan to suck the old oil out of the top of the engine. That would leave any sediment in the sump to contaminate the fresh oil. I would want to see and feel that sediment to check for any solid particles. Why can't you drain the oil from the sump plug?

Hello Keith,

I’m of the same mind as Cliff, and question why you would want to syphon the oil out rather than remove the drain plug - take it your 10 year old model has a drain plug, and appreciating some more recent model don’t. 

Re Mobil 1 5w/30:- a good oil ( I use it in our non-Audi) available in Wilco for around £24,  but the preferred oil for the Audi is the recommenced/was recommended Quantum brand, and I use their Longlife 3, (on EBay) which although will last for c18k, I change it every year at around 6 to 7K. 

Re. Blackness of oil, I think you will gain more by getting your current oil up to temperature (min 10 mile run) and leaving it to drain off for at least half an hour. Ok, using the Ford oil for a couple of days should be fine, but I would not trade off the benefits of this against syphoning rather than draining. 

As a matter of interest, what oil filters are you using Keith?

Kind regards,

Gareth.

I've done the oil change now, I did it the conventional way with the drain plug. My main reason for considering the syphoning route was ease of access and reluctance to use axle stands. I sorted out those issues, but the job was still a faff, as the convertible has a metal undertray held in with 20 ish bolts! I didn't run the ford oil through it, just went with the Mobil 1 esp.

Glad I did it the right way.

Better safe than sorry.