Would somebody ever deliberately overfill an M271 with oil?

Page may contain affiliate links. Please see terms for details.

Borris1954

Active Member
Joined
Feb 4, 2013
Messages
414
Location
South Bucks
Car
S204 C 250 CGI BlueEFFICIENCY, R170 SLK 230, B 180d AMG Line
The impending ULEZ expansion has finally twisted my arm and forced me to part with my beloved S211 320 CDi - something I would not have done otherwise, As a result on Monday I travelled "up North" and part-exchanged my E Class diesel estate Estate for 59 plate petrol C Class Estate. It a S204 C250 CGI BlueEFFICIENCY.

Cosmetically its in lovely condition, top of the range spec and has just turned 100K miles (barely run in?). The test drive was fine and the engine was super quiet with no rattles so I closed the deal and brought it home.
On the way home when starting it up after a pit stop at Hilton Park Services there was a definite rattle and slight hesitation to start but once running all fine. Over the next couple of days I noticed a pattern I have since read about for these M271 engines of a rattle free start up from cold and when immediately restarting when hot but a definite rattle if left for a short period and then restarting. So I think I am going to need to get the Cam Adjusters and chain etc sorted very soon? Up to this point there was no Engine Management Light (EML) on.

Despite the claim it was recently serviced I decided that very first thing I should do was change the oil and refill with correct MB stuff. This was when I discovered the sump contained just over 7.5 litres of oil and not 5.5!! I couldn't smell any petrol (although post COVID my sense of smell isn't a sharp as it was) and there was definitely no coolant mayo. Given no lights on the dash it would seem a deliberate overfill unless the dealers apprentice topped it up incorrectly during PDI.

Anyway on restarting after the oil change the engine was reluctant to start and rattled quite badly for a few seconds once it did start. After this it was then all nice and quiet again. BUT the EML is now on so I hooked it up to my SDS and ran a Quick Test and low and behold I now have:

P001762 "The position of the exhaust camshaft (cylinder bank 1) is implausible relative to the position of the crankshaft. The signal comparison is faulty" Both current and stored.

The car now seems to start Ok from cold with just slight rattle a second or two. I am now not inclined to drive the car any great distance until I have had the Cam Adjusters etc looked at.

But the big question in my mind is would some unscrupulous person dump in extra oil to try and mask this problem or am just being super suspicious...
 
Last edited:
Just for completeness when I first did an SDS scan on getting the car home (when no EML on) I had the following code

P233723 The knock limit of cylinder 2 was exceeded. No signal change: Voltage level is too low
 
Overfilling with oil would be a pretty poor attempt to hide engine faults. Be careful with codes from multi brand scanners, they can send you down the wrong path. You may find that one code will have others hidden behind it, then you are in danger of playing parts darts.
 
Some MB models throw a warning message on the cluster for oil level too high - I had this once on our 2007 Vito after a service.
 
Yes agree with you about scanners - I got caught out playing parts darts courtesy of an iCarSoft scanner when trying to fix a PTS parking sensor issue on my S211.
So I bit the bullet got my own MB Star Diagnostic System and have never regretted it. It's even more true for my 1996 SLK 230 where nothing else gets remotely close to using the pukka HHT module of SDS.

The codes above are from Xentry.
 
They could have added a litre or two of 'snake oil' oil additive in an attempt to quieten down a noisy engine. ?

I would also (personally) not share your view that at 100K miles that it is 'barley run in' . At 100K miles a M113 V8 is 'barely run in' . Not sure about a petrol M271 .

Best of luck with it . Let us know how things go 👍
 
Yes agree with you about scanners - I got caught out playing parts darts courtesy of an iCarSoft scanner when trying to fix a PTS parking sensor issue on my S211.
So I bit the bullet got my own MB Star Diagnostic System and have never regretted it. It's even more true for my 1996 SLK 230 where nothing else gets remotely close to using the pukka HHT module of SDS.

The codes above are from Xentry.
Yes I know exactly what you mean. I have both Star and icarsoft CR Pro and find that whilst Star is a bit quirky to use, it is by far the better tool for MB vehicles.
 
Instead of speculating in the actions of the previous owner... just get the timing chain (and hydraulic chain tensioner, and chain guide, and camshaft wheel sprockets) inspected for peace of mind.
 
Last edited:
But the big question in my mind is would some unscrupulous person dump in extra oil to try and mask this problem or am just being super suspicious...


I don't see how an oil overfill would mask the problem. I've done many oil changes on an M271 and in my experience the 5.5 L stated volume does not match the dipstick Max reading or anywhere near it. On my first change, I drained more than 5.5L, perhaps not 7.5 but certainly 6.5. I have always added a measured 5.5L since and it only brings the level to approx.1/4 to a 1/3rd of the way between min and max.

Someone has sold you a lemon and perhaps thought they could mask it with additional oil but I see no mechanism that would make that work. The rattle occurs until the cam chain tensioner is pressurised with oil and the oil level would not impact on how long that takes provided it's above the min mark.
 
Instead of speculating in the actions of the previous owner... just get the timing chain (and hydraulic chain tensioner, and chain guide, and camshaft wheel sprockets) inspected for peace of mind.
^this!
 
Yes I did an oil change and got 6.5 out after always being main dealer serviced. I do it myself now and it takes 5.5 to get it to 3qtrs up the dipstick. Hope you get it sorted
 
Yes I intend to do exactly that. It just occurred to my suspicious nature that excess oil was added for some reason but in the end its irrelevant as I intend to sort the car properly. Interestingly I just needed to move the car and note that the EML is now out so I guess that DTC is no longer current. Thanks to all who responded and I will post again when(if?) I get it all sorted.
 
Yes I intend to do exactly that. It just occurred to my suspicious nature that excess oil was added for some reason but in the end its irrelevant as I intend to sort the car properly. Interestingly I just needed to move the car and note that the EML is now out so I guess that DTC is no longer current. Thanks to all who responded and I will post again when(if?) I get it all sorted.
I take it was a dealer sale buddy . Are you sure you don’t want to throw the cat back to them ? It’s going to be £1000+ for cam gears, chain and tensioner and that’s if there’s no other issues .
 
Not cheap but you have to remember Quality doesn't cost but pays in the long term. If you want to use genuine MB parts (which I did) then you are looking at about £1.2K for the stuff you will need to do the job properly (including new thermostat as it will probably break on removal, coolant, oil and filter change etc etc). Then there's labour on top if you opt not to do it yourself which is probably about a day. If you do it yourself you will need to factor in the special tools to hold the crankshafts and break and redo timing chain links. Hope that helps.
 

Users who are viewing this thread

Back
Top Bottom