Small Oil Leak, Any Ideas




Towards the end of last year I noticed after motorway (highway driving) the next day in the garage there would be a small patch on the garage floor (At first I thought this may have been overspill from a recent service), I dont do many highway driving so it was a while again before I did and noticed it again a couple of months after the service so booked the car in (which it was November/December). They had the car in and noticed spill on the undertray too and said I had a leak and they needed to find it. They called me to say it was the engine oil pan gasket and replaced. I have not done much highway driving since but there were no marks on the garage floor so thought all was well until today! the car was on the ramps and he let me stand under the car when I noticed two separate dark stains on the undertray on the front left passenger side in UK) near the primary cat. I got a torch to look around and there was what looked like fresh oil on the topside of the engine oil pan and around the lip so something higher up had come down onto it, I looked further up and the only thing I could see was fresh oil on a screw on the engine side of where the bell housing for the gearbox screws into.
So from the above it looks like the leak is higher than the engine pan.
Any ideas guys please? Much appreciated
Last edited by Phil_T; Jul 12, 2019 at 09:17 AM.
Also, UK driver side is front right (why they call it RHD). Left and Right designation is determined while you're sitting in the car looking out the front windshield.




Yes fixed its passenger side which is front left. (Car is RHD)




The screw with oil was around this area, then oil on the pan lip below and the undertray.
It was all over the side and lip of the pan circled below.
Last edited by Phil_T; Feb 28, 2017 at 02:33 PM.
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The Best of Mercedes & AMG
I already have them, just haven't got around to them yet.




What does HB and VC stand for?
The car only has 24,000 miles on which I have put on from new, as above what does VC stand for?




Last edited by Phil_T; Mar 1, 2017 at 01:54 PM.
What does HB and VC stand for?
The car only has 24,000 miles on which I have put on from new, as above what does VC stand for?




I noticed last week too I could smell abit of oil burning which I have not smelled before and it was also the 2nd or 3rd time the oil cap and valve cover top around it had oil stains after cleaning it previously.
https://mbworld.org/forums/c63-amg-w...mon-issue.html




1. This oil leak appeared after the 3rd year service on the gearbox which the leak is in that area.
2. I came back to them with this problem after the 3rd service stating there is now an oil leak after the service as it was on my garage floor! The car at this time still have 2 weeks left of the 3 years manufacturing warranty.
3. At the time of point 2 they could not get car booked in before the 2 weeks but I bought Mercedes extended warranty. I stated this happened as above and was the dealers fault as the leak is also in the same area worked on but the dealer said the leak was coming from an area that was not worked on (They described at the time in person where leak was and that it was not covered by extended warranty because it was a seal)
I therefore paid £350-£450 including oil to fix what they said was the problem
4. I returned to Mercedes at a later date of using the car only a few times over serveral months that there was oil on my garage floor again, I paid £100 diagnostics for them to tell me they cant see where the oil is coming from, We have cleaned it off so come back after 1000miles (I explained this is a second car so will take a while)
5. I went back after 700 miles over the course of several months, paid £100 diagnostics again for them to say we cant see where it is coming from and you still have 300 miles left to do. I asked them what they will do next and they said they will need more diagnostics at £100 x hours they need to find. They also said if they find it to be coming from a certain area they cant reach that would be engine out job at £100 x 10 hours!!!! So I went away and drove the car another 300 miles.
5. A few months go by I have the car up on some ramps at a garage which I saw all the oil again so cleaned it all off, booked the car into Mercedes while driving the car a few days
6. Finally the car went back into Mercedes and all they said was there was no more oil leak!!
7. A few months go by with the car being driven 4 short times, It went in for its service this Monday which they said you have an oil leak (No ****) So I explained everything above.
There is no way I should pay for anything, this happened after the 3rd year gearbox service with the leak around that area so something has obviously happened. I have paid for one so called fix plus two lots of diagnostics.
I have also found 10 examples on UK forums alone with some more on this forum stating they have a gearbox oil leak in the same area, same car and after 3rd year geabox service!!! Coincidence???? I think so!!
Last edited by Phil_T; Jul 27, 2018 at 08:13 AM.
Oil leaking from block/trans area
I have a leak from above the rear of the pan, between the engine block and trans. Would this possibly be the PCV leakage draining down? Theres a rather large amount dripping, my splash pan was full and spilling out.




I went to pick up the car yesterday but have to leave it with them again because fixing a seal to do with the aircon has now made a hissing noise and intermittent rattling when the fans inside are blowing or if the ac is on.
In regards to the rest of the oil problem they have done the upper pan seal which I had to contribute to but at their cost they have done the lower pan seal again and done the gearbox rear main seal because it had to be pulled to do the upper pan. They also noticed while working on the car the drivers side engine mount was slightly leaking (not same side oil leak was from) so they replaced the drivers side engine mount (explains why I could probably feel a slight vibration through the car and when my leg was against the tunnel)
So hopefully the oil leak is fixed but time will tell, I just hope they can fix the ac problem. At a guess from reading other posts its eitheir ac regass, condensor or something else?




After the service last year I took their word for it that it was fixed (upper pan leak) and put the car away for 11 months under the cover and on the trickle charger. (Had health issues which is why car was garaged)
The service is due next week so took the car out for a run and the gearbox isn’t shifting right almost like its slipping, in comfort the changes are not smooth up or down and on two occasions it has changed from 3rd to 2nd that harsh it was like the car had been rear ended!
I heard the manager was leaving before my upcoming service so I rung Mercedes HQ for them to get in writing what he told me last year “if for some reason there is still an oil leak we will fix this free of charge due to misdiagnosing wrongly twice previously” Mercedes Hq also spoke to him to say that I am having gearbox issues since the upper pan leak “fix” that they also replaced the rear main seal at the same time.
The manger has turned round to Mercedes HQ and said he never told me they would fix it for free if there was still an oil leak, he also said they never pulled the gearbox away from the engine!!!
Wow I honestly don’t believe he has lied about all this, As last year they also said they fixed the upper pan leak by resealing without pulling the engine!
This cannot even be done! Also how do you replace a rear main seal without removing the gearbox? Luckly I have paperwork that says they did the rear main seal!
This morning I have taken it to a garage for inspection and guess what!! Still leaking from upper pan and now leaking from gearbox bellhousing between the engine after they pulled the gearbox!!! No wonder it’s shifting weired.
Last edited by Phil_T; Jul 12, 2019 at 09:12 AM.




- Firstly should that lower engine oil pan be sealed with selant? I am sure it was a gasket and previously I couldn’t see no sealent round there at all.
- Am I right in thinking if there is a problem with the rear main seal which they changed and also because the new 2nd oil leak they have caused means engine oil is getting into the gearbox and onto the flywheel? Which would also explain the slipping and jerky gearchanges.
- You cannot do an upper pan job without removing the engine? If you look it some of the pictures there is loads of black sealent on the block like its been done on the outside




