Doing my own servicing?

It's a petrol. When I used to do this myself the oil stayed fresh/clear for a good few weeks.

Rob

A lot of sumps nowadays seem to be shaped to prevent full evacuation of the old oil via the drain plug, and it depends on the individual mechanic if using the vacuum pump method on his efforts to get it all out.

The cynic in me thinks that if the mechanic does not exacuate all the used oil, then less has to be replaced whilst charging for a full replenishment, therefore more profit for the dealer, and better bonus for the mechanic.

David

Even if a litre was left in, the resultant mix should still look noticeably 'cleaner' on the dipstick however.

Chris

Well yes, (if you have a dipstick), but I changed the oil in one of our cars last month (a petrol engine), around 4,000 miles after a 'main dealer' oil change, which was before we got that car.. Why, because of a fault that left one spark plug absolutely black with carbon. I wanted to be sure that the oil was not contaminated with fuel, so I changed the oil and filter.

When I change the oil, I have the car slightly leaning to have the drain plug at the lowest level, and also use a vacuum pump to remove as much oil as I can, including the filter housing. It is not a spin on filter like the Focus.

Anyway, 800 miles later, after the fault was 'fixed' (ie, no more mis-fires), the new oil was pretty black. This is rather contrary to my experience of changing oil in a petrol car.

I shall keep an eye on it. I do a periodic 'spot test'.

I would like to do a compression test, but there is a procedure for it on that car whereby the dealer software has to put the ECU into a special mode to allow it.

David