Mercedes C220d W205 - Reduce Engine oil after service

Mercedes C220d W205 - Reduce Engine oil after service

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Raptor7000r

Original Poster:

250 posts

71 months

Wednesday 22nd May
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We have a C220d w205 facelift model, the 2019 which we recently had serviced.

After service and checking the oil electronically, we seen the engine oil was above the maximum and said to reduce engine oil, there was no active warning although this did pop up once. It did often change to just about maximum to above maximum.

We took it back to the garage who checked the oil sensor to check if faulty and drained a little. This then showed at just under maximum, the garage said during dpf regens it could increase resulting in the error. A month or 2 has passed and we notice the same again, sometimes the reading is at maximum, other time it goes above and says reduce engine oil. We've checked when cold and hot and there's no difference still both variables.

Just at the weekend we done a 35 mile trip then 35 miles back and oil level showed as above maximum, just checking it yesterday it showed at under max and green at the correct level when cold.

Has anyone had any experience of this? Not sure if we should drain a little more out but it doesn't appear that when the engine gets warm it increases for example.

trevalvole

1,085 posts

35 months

Wednesday 22nd May
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You probably know this already, but I understand that when a car does a forced dpf regen, it can deliberately inject more diesel to increase the temperature of the exhaust and burn off the particulates, and under some circumstances, this extra diesel can end up in the engine oil, raising the level and also not helping engine lubrication.

Do you do lots of short journeys that mean the exhaust wouldn't get hot enough to burn off the particulates without the need for a forced regen?

Edited to add that it probably did a forced regen sometime during your 35 mile journeys, which it probably wouldn't be able to complete during much shorter journeys.



Edited by trevalvole on Wednesday 22 May 14:22

Raptor7000r

Original Poster:

250 posts

71 months

Wednesday 22nd May
quotequote all
Yeah, the car does get a lot of short journeys, Its the family car and is more or less used for short journeys nowadays rather than the 50+ miles that I occasionally used to use it for before.

How often are DPF regens done on these? Issue now is we tend to do a lot less miles and 3-5 miles trips regularly and irregularly 10+ depending on journeys.

I have a petrol we can use for local but like to keep mines for the more entertaining jaunts.

Sheepshanks

33,179 posts

121 months

Wednesday 22nd May
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Don’t know if it’s still the case but even before dpfs it was always a thing with diesel Mercs to leave the oil a little under full - mine held 6.5 litres and the dealer and the indie who took over would fill it to 6.2 - if filled to max they’d show a high oil level warning, supposedly as oil expands when hot.

Your usage of the car isn’t ideal - mine would be well into the teens of miles before being properly warmed up and wife’s much more recent Tiguan was the same, although that coped fine with shopping and school run use, even with often interrupted active regens.

trevalvole

1,085 posts

35 months

Wednesday 22nd May
quotequote all
Sheepshanks said:
Your usage of the car isn’t ideal - mine would be well into the teens of miles before being properly warmed up and wife’s much more recent Tiguan was the same, although that coped fine with shopping and school run use, even with often interrupted active regens.
I think you're right to use the term active, rather than forced, which I now remember is for when someone with the appropriate kit manually initiates a regen.

Raptor7000r

Original Poster:

250 posts

71 months

Wednesday 22nd May
quotequote all
Sheepshanks said:
Don’t know if it’s still the case but even before dpfs it was always a thing with diesel Mercs to leave the oil a little under full - mine held 6.5 litres and the dealer and the indie who took over would fill it to 6.2 - if filled to max they’d show a high oil level warning, supposedly as oil expands when hot.

Your usage of the car isn’t ideal - mine would be well into the teens of miles before being properly warmed up and wife’s much more recent Tiguan was the same, although that coped fine with shopping and school run use, even with often interrupted active regens.
I think this is a decent shout, was thinking if it continuously happens causing over indication of oil, probably better to drain half a litre so it allows for the increase when doing regens. Will likely go down this route as the car doesn't seem to use any oil in between services either.