Thick oil on bottom of filler cap

[kingy1912]

---

Hi all,

So i have had an oil leak from what looks like the cambox seal (has same issue with 2016 B9) in behind the DPF turbo cover area. Anyway due to this i had to top up and noticed a build up oil thicker oil sticking to the bottom of the cap. Wiped it off and drove the car for a bit and when i got back there was oil sticking to it but just ordinary engine oil.

I think it may be oil building up and sticking to it and due to no oil flow in this area it just builds up. My thinking is with these engines having high carbonisation of the oil that the oil up there is dirty and just clinging to the cap. Oil changes are done every 10K and garage has never raised this with me before. It is the first i have ever had the filler cap off so i have no idea what it was like previously. I did notice that the filler has a slopped ledge on it leading in to the rocker area and seems to restrict the flow of anything other than splashes in to the filler area. Car runs fine, sounds fine and appears to be no different than it has been before.

No there is a couple of things that have went on previously that may or may not be part of this. 

1) The car from new (June 2020) until April last year was serviced using the same grade as factory fill this was Total Quartz Ineo First 0W30 but after supply issues it changed to same grade C2 spec Comma oil. Now it appears due to issues with the engine this oil was changed from Total Ineo First 0W30 to Total Quartz Ineo First Extra 0W20 C5 spec across all engine models. I found out about this because my usual place could not get me in for a change so i took it to Citroen and they filled it with this. They provided me with an updated service schedule print out and the up to date oil info was presented on this.

2) When the new info about the 0W20 grade came out I believe production scale was not large enough to supply demand at that time so oil changes were done using Arnold Clarks own brand 0W20 C5 spec approved by citroen for use until the new Total grade was available. I am now on to the Total 0W20 C5 as i can buy it at a reasonable price from TMS.

Now is it possible that the changes from different oils have caused some kind of reaction causing this build up?? When i changed from 0W30 to 0W20 i called emailed total and they assured me that there should be no issue when moving to the newly recommended grade of oil. Not to disregard that the grade change may be the issue i am more focused on the change from the Arnold Clark oil to the Total 0W20 as this has been the most recent change. It is going to Citroen in 10 days to have the cambox seal replaced so i will ask them to investigate this but i think i will get another oil change. The last change 6K ago was the first change moving from the Arnold Clark oil to the Total.

I have also seen someone mention that it can be a result of an overheating of the oil causing oil condensate to build up. This is worrying considering these engines get really hot when doing a regen and hot oil seems to be part of the working process of these engines. 

I have added a link with the pic of the cap showing a small build up on the cap after my first drive since cleaning the cap off. This stuff was thin and just looked and felt like ordinary splashes of engine oil. Possibly over time it builds up in layers with the thinner stuff running off and the dirtier elements of the oil clinging together.

https://drive.google.com/file/d/1Y8IjgEd...drive_link

[Cumbrian]

---

Hi all,

So i have had an oil leak from what looks like the cambox seal (has same issue with 2016 B9) in behind the DPF turbo cover area. Anyway due to this i had to top up and noticed a build up oil thicker oil sticking to the bottom of the cap. Wiped it off and drove the car for a bit and when i got back there was oil sticking to it but just ordinary engine oil.

I think it may be oil building up and sticking to it and due to no oil flow in this area it just builds up. My thinking is with these engines having high carbonisation of the oil that the oil up there is dirty and just clinging to the cap. Oil changes are done every 10K and garage has never raised this with me before. It is the first i have ever had the filler cap off so i have no idea what it was like previously. I did notice that the filler has a slopped ledge on it leading in to the rocker area and seems to restrict the flow of anything other than splashes in to the filler area. Car runs fine, sounds fine and appears to be no different than it has been before.

No there is a couple of things that have went on previously that may or may not be part of this. 

1) The car from new (June 2020) until April last year was serviced using the same grade as factory fill this was Total Quartz Ineo First 0W30 but after supply issues it changed to same grade C2 spec Comma oil. Now it appears due to issues with the engine this oil was changed from Total Ineo First 0W30 to Total Quartz Ineo First Extra 0W20 C5 spec across all engine models. I found out about this because my usual place could not get me in for a change so i took it to Citroen and they filled it with this. They provided me with an updated service schedule print out and the up to date oil info was presented on this.

2) When the new info about the 0W20 grade came out I believe production scale was not large enough to supply demand at that time so oil changes were done using Arnold Clarks own brand 0W20 C5 spec approved by citroen for use until the new Total grade was available. I am now on to the Total 0W20 C5 as i can buy it at a reasonable price from TMS.

Now is it possible that the changes from different oils have caused some kind of reaction causing this build up?? When i changed from 0W30 to 0W20 i called emailed total and they assured me that there should be no issue when moving to the newly recommended grade of oil. Not to disregard that the grade change may be the issue i am more focused on the change from the Arnold Clark oil to the Total 0W20 as this has been the most recent change. It is going to Citroen in 10 days to have the cambox seal replaced so i will ask them to investigate this but i think i will get another oil change. The last change 6K ago was the first change moving from the Arnold Clark oil to the Total.

I have also seen someone mention that it can be a result of an overheating of the oil causing oil condensate to build up. This is worrying considering these engines get really hot when doing a regen and hot oil seems to be part of the working process of these engines. 

I have added a link with the pic of the cap showing a small build up on the cap after my first drive since cleaning the cap off. This stuff was thin and just looked and felt like ordinary splashes of engine oil. Possibly over time it builds up in layers with the thinner stuff running off and the dirtier elements of the oil clinging together.

https://drive.google.com/file/d/1Y8IjgEd...drive_link

Which engine do you have fitted?

[ComboLifer]

Is the oil creamy?
Head gasket?
Any oil in the water reservoir bottle?

[kingy1912]

Is the oil creamy?
Head gasket?
Any oil in the water reservoir bottle?

Nope nothing like that and can only assume it is temp related as i have not had the problem over the summer.

[boop]

Ohhhh, that's nothing. See mine at 10K:

   
   

[notsofast]

The sludge on boop's cap looks like an oil/water mix, whereas kingy's looks more like just oil.  I would go outside and look at my cap for comparison, though I'd have to clear several inches of snow off the bonnet first, so I'll leave that for now.   I've never had anything that looks like boop's cap sludge though, and if I saw that I'd want to do other checks to clarify if it might be a head gasket problem (though reading around suggests that milky sludge can also result from doing short trips and the engine not getting hot enough to burn off condensation).

[boop]

Yes, it has disappeared since.

[Multispacer]

Yes, it has disappeared since.

I think personally, I would be changing the oil more often [than the manufacturers recommend] nowadays, especially on seeing images such as in this thread. I've always stuck to the 6000 miles [that used to be the norm on older generation diesels] 

The reason behind this was [and I've told this story before, so apologies if you've read it on one of my older threads] A number of years ago at work the subject of oil changes came up [back when most people used to do their own servicing] One of my work colleagues had a brother who worked in the technical laboratories for a very large multinational oil company. As a project one year they got hold of as many commercially available engine oils they could from around the World [and we're talking a lot of different oils here] and subjected them to multiple tests in the lab. As you might guess there was a lot of data/results across the sample range. The one thing that was common in the results across the board on all the oils from very high priced to the cheaper brands was they all showed a noticeable degradation in performance after 6000 miles. Now I know many might argue that oil technology has probably moved on since those tests but so also has the power output that we tend to demand from smaller modern ICE engines, so I suspect oil still falls off in performance after that kind of mileage. I remember the guy saying at the time, that after they had the test results, all the lab staff used to change their oil every 6000 

[evdama]

Yes, it has disappeared since.

I think personally, I would be changing the oil more often [than the manufacturers recommend] nowadays, especially on seeing images such as in this thread. I've always stuck to the 6000 miles [that used to be the norm on older generation diesels] 

The reason behind this was [and I've told this story before, so apologies if you've read it on one of my older threads] A number of years ago at work the subject of oil changes came up [back when most people used to do their own servicing] One of my work colleagues had a brother who worked in the technical laboratories for a very large multinational oil company. As a project one year they got hold of as many commercially available engine oils they could from around the World [and we're talking a lot of different oils here] and subjected them to multiple tests in the lab. As you might guess there was a lot of data/results across the sample range. The one thing that was common in the results across the board on all the oils from very high priced to the cheaper brands was they all showed a noticeable degradation in performance after 6000 miles. Now I know many might argue that oil technology has probably moved on since those tests but so also has the power output that we tend to demand from smaller modern ICE engines, so I suspect oil still falls off in performance after that kind of mileage. I remember the guy saying at the time, that after they had the test results, all the lab staff used to change their oil every 6000 

Plus the fact that modern engines have to keep much more of their waste products inside between services which quickly turns the oil into soup.
I do mine twice yearly which sometimes equates to as little as 3k.

This thread reminds me of the cottage cheese you would find under the olive-green rocker boxes of BMC A-series engines...

[Mark604]

I could be wrong because I've not looked at it for a long time but after an oil change and the spanner symbol is reset I think it counts down from 20,000km to the next change. I do mine every 10,000km (6214 miles) anyway. At my roughly 25,000km every year that is five times every two years.