benking

Hi Everyone,

I have an oil consumption issue on my 2006 CLS500 (w219) with the M113 engine. The amount I have to top up seems to vary wildly with usage, with mild running on the motorway its approx about 1L/1000Miles however I have seen that go down to about 1L/300Miles with heavy usage of the right foot! The car also has a fairly significant oil leak (probably rear main seal too but I can also see leaks from valve covers and breather chambers). I have been running the car for a while as the burning oil seemed to actually only be a small amount of blue smoke on hard acceleration until recently it failed its MOT on: Exhaust emits excessive dense blue smoke during acceleration (8.2.1.2 (g)).

The car has now done 172,000 miles and the previous owner lost some of the service history so not entirely clear how well it was maintained.

To try and determine what is going on I performed a compression test, inspected the spark plugs and inspected the cylinder walls with a bore scope. Compression seemed all good however when inspecting the cylinder walls I saw some ring shaped ridges further down the cylinder wall than TDC which I thought were a little strange.





Is this something to be concerned about? I do have full images from all tests so if the above image is not likely to be the cause I will post all the images to try to figure out what the issue is.

benking

Just for reference the plug for the above cylinder seemed normal, see attached image: