Hi guys n gals.

My motor is due it's MOT soon so I'm giving it an oil and filter change while it's in there (do this every 6 months).

I've heard a lot of talk about how much oil to put in and the general consensus is to only fill it 3/4 full to allow for compression.

Is there any truth to this at all??

Mike.

The max line is the max line for a reason.. Just fill it right up.

Michael I have the 2009 mk2.5 1.6 zetec focus. I to have heard a lot of talk about how much oil to put in and the general consensus is to only fill it 3/4 full to allow for compression.

Not sure what to think myself but the manual states between min and max and I though that filling to the max or above slightly might explain why I have heard of some older zetec engines (mk4 fiesta ect) the oil seals would give causing the car to burn a little oil.

I always used to fill the old HCS engines up to the max mark with no problems at all but on the focus i have come up with a compromise. some say Max and ford say Between Min Max (although some ford dealers fill to the Max and a little past......) I sort split the difference. a Little below Max and Little above "Between Min Max".

I have included some pics of the manual Diagram oil levels and the red line I marked is what i fill my car to now. I dont think the full Max would matter too much but I would not go over it although To reassure myself I just split the difference between both recommendations and ended up somewhere in the middle lol!

Hope this helps.

I personally suggest up to about 80% and no more. unless they are flushing the engine altogether, there is oil still around in the turbo and the engine itself, which will drain over time.

Michael I have the 2009 mk2.5 1.6 zetec focus. I to have heard a lot of talk about how much oil to put in and the general consensus is to only fill it 3/4 full to allow for compression.

Not sure what to think myself but the manual states between min and max and I though that filling to the max or above slightly might explain why I have heard of some older zetec engines (mk4 fiesta ect) the oil seals would give causing the car to burn a little oil.

I always used to fill the old HCS engines up to the max mark with no problems at all but on the focus i have come up with a compromise. some say Max and ford say Between Min Max (although some ford dealers fill to the Max and a little past......) I sort split the difference. a Little below Max and Little above "Between Min Max".

I have included some pics of the manual Diagram oil levels and the red line I marked is what i fill my car to now. I dont think the full Max would matter too much but I would not go over it although To reassure myself I just split the difference between both recommendations and ended up somewhere in the middle lol!

Hope this helps.

Hi sonic.

I think I will try to get it somewhere around the 80% mark as you and jeebo suggest.

I just don't like topping things up all the way because there is no room for error!

I like to err on the side of caution plus, I can see the reasoning behind the "compression" logic....

Unless you know your engine is losing/using a lot of oil (e.g. leaking, worn piston rings or turbo bearings) then play safe and only fill the oil level to around 75% - 80%; here's a good reason why ...

Some diesel engines with a DPF use extra fuel (i.e. a 'rich' mixture) to help raise the temperature of the DPF during regeneration in order to burn off the accumulated soot in the DPF. As a consequence some of that extra fuel can find it's way into the sump and if too many automatic DPF regenerations fail then your oil level can rise quite a bit.

So if your oil level starts out at maximum then it can easily go over maxiumum; get that level too high and you can get to the point where engine runaway occurs.

Diesel engine runaway is where the oil level is so high that oil either gets forced past the piston rings or creates a lot of oil mist (which due to emission regulations) is fed back into the inlet. As a diesel engine is an oil burner even switching off the ignition won't stop the reaction. Stand hard on the footbrake, dip the clutch, put the car into 4th or 5th gear and let the clutch out suddenly; hopefully the engine stalls.

Do a google search for videos of 'diesel engine runaway' - they very graphically illustrate what I've just described.

If you know your engine's regularly losing/using some oil then you can always keep a 1L or 2L in the car.

no problem Michael. I think 80% as James said is a dead on mark.

i would always recommend that the oil level is checked around once a week just so you know if it drops or anything. I know of people (Father in law lol!) who never checks oil level until the oil light comes on, then problems lol! although i have him now in the habit of checking weekly so at least some good as come out of it lol!

James would you say the red mark on my diagram looks ok for my engine the 1.6 zetec?

personally, I would say thats too low. your better off having that distance between the max and heading inwards (just invert your red line)

Surely when ford designed this engine, they took into consideration that topping the oil up by the average Joe who doesn't know any better. I can't believe they would spend probably millions designing an engine and overlooked this.

What I mean is surely they have selected the min and max marks with consideration to the fact that the ecu can put in more fuel for the engine to do it's thing with the dpf and that the oil level could be on the max mark beforehand - otherwise what's the point in it..

Once the oil is contaminated with fuel it's going to need changed anyway.

I don't disagree stef, I personally prefer to play it safe and avoid max in these things to prevent other problems possibly coming about

Sent from my MY SAGA C2 using Ford OC mobile app

FYI I've just had myDPF removed and remapped (which I highly recommend if you know a guy in an MOT station) and they all say around 80% for compression.

I'm sold anyway, 80% for me with an oil change every 6 months.

James my apologies you are correct my red line is far too low.

when i was up loading the pic i was rushing and mixed up the min and max mark. I have included the pic again but it has been fixed. sorry everyone for that. but yes i agree around 80% is best. the green line in my pic is where i fill mine to now. does this look better James?

ok I clicked post before i added the image. so here is the image hopefully this time lol! Its been one of them days lol!

Looks perfect sonic :-)

That is certainly where I would look to fill it to personally!

Thanks fellas, I will be using this marking point in the future.