Hmm - well a non franchised garage has already put 4 litres in during a recent service

I had exactly the same issue myself with my local Ford Main Dealer a few years ago.

After getting my car back after a full service I noticed that, on the receipt, they had put 5W-20 oil into the engine. Throughout the handbook it religiously states that 5W-30 should be used and absolutely nothing else. Car is Ford Mondeo Mark 3 2.0 Petrol, by the way.

Of course, I took this issue up with the dealership. Their service manager assured me that Ford had now changed the oil specification for my vehicle and that 5W-20 oil was perfectly suitable for it! I have to say that I wasn't convinced but I let it go at the time.

I left the 5W-20 oil in the sump until the next service, when my trusted local independent garage put the recommended 5W-30 in.

I did notice, while my car was running on the 5W-20 oil, that some of it was being used up; I had to top the oil up by a small amount a couple of times before the next oil change was due. I hadn't found it necessary to have to do this previously, nor since.

My bet is that the Ford Main Dealer no longer kept 5W-30 oil because I believe all the modern Ford engines use 5W-20. They obviously purchase their oil in substantial quantities, probably thousands of litres at a time, and I don't suppose that they consider it's worth their while to purchase an alternative oil as well which they probably wouldn't use a great deal of.

Needless to say I never went back to my local Ford Main Dealer and my car had always had the recommended 5W-30 oil in it's engine ever since.

Edited by Galaxy on 01/02/2018 at 20:29