SLK engine problem

[Neil Richards]

I am looking for a specialist in the Northwest preferably, who has experience in rebuilding or part rebuilding the 272 engine.

My problem I think is related to the premature balance shaft chain/gear wear (engine light on) which is well documented, law case in USA etc.
My car is an SLK 280 registered in 2007, owned from new and has only 65k miles. I really thought that the purpose of chain drive over belts was improved reliability and longevity......not the case!

It currently still runs well and the serial number of the engine is later than the 468993 stated in other reports which indicates it has the modified balance shaft/gear.
The pickup magnets were also replaced last year but the problem has returned.
I would like to get the engine repaired but have seen the complexity of the work on U tube and I am a little nervous about having the work done by some one as a first time. I also wonder how reliable the replacement parts are likely to be.
There must be a cause for this excessive premature wear. I have seen reference to only using Mobile 1 0w/40 fully synthetic oil and fleece oil filters. I do know that my Mercedes dealer used Castrol products from new, no idea if this is really a cause.

I have been in touch with a specialist engine builder who informs me that Mercedes do not make over sized pistons for this engine variant so cannot do a fully re-conditioned build if it needed it. A further worry if it were stripped down and further damage discovered.

Any advice greatly appreciated
Neil

 

[BTB 500]

There are three different balance shaft issues ... engine number ranges are in post #2 of this thread (you need to be over 895140 to be completely in the clear):

http://www.mbclub.co.uk/forums/engine/137229-complete-m272-engine-thread.html

 

[Neil Richards]

Thanks very much BTB 500. Really good information. My serial number is 27294230567801 so suspect solenoids seems to be a consideration, although these have already been done last year.

I have found out that MB Tech in Warrington have done the replacement balance shaft job so may give them a try. Will get them to double check fault codes and solenoids before taking the engine out.
Engine light seems to stay on for nearly a week then goes out for three days. Back on now.

Still wonder about the oil.... MB main dealer has used Castrol products with these references -
5w 40
229-3
5w 30
8w 30
Then the independent garage used
5w 30 Long life Quantum
5w 30s

The service guide refers to Mobil 1. Are the castrol products above correct/equivalent?

 

[Neil Richards]

Since had a look at the oils sticky thread.
Not really enough detail in my service record to actually identify what oil was used.
Inconclusive as to if this has contributed to premature wear of the balance shaft or indeed if the fault is the solenoids/magnets. The MB guidance bulletin was dated April 2009 and I have seen reference to the pickup magnets being a delay tactic/ploy so work was not needed in warranty!
Wondered if anyone any experience of later serial number (27294230567801) balance shafts wearing at only 65k mileage?

Testing and reporting to take place soon
Neil

 

[SLKGirl]

Wouldn't have thought there was much MB could do, as long as the oil used meets their specification, mine has to meet 229.5

You can simply select the MB spec on the drop down list on this link and it tells you what you can use

https://bevo.mercedes-benz.com/bevolisten/229.5_en.html

 

[Neil Richards]

Can't realy pin down the oil types actually used, but looking to get the balance shaft replaced if it actually needs it.
One comment i heard recently, is that is that the balance shafts are matched to the engine/crankshaft and that if changed they don't actually match and don't run the same!
Does anyone know if there is there any truth in this?

 

[st13phil]

One comment i heard recently, is that is that the balance shafts are matched to the engine/crankshaft and that if changed they don't actually match and don't run the same!
Does anyone know if there is there any truth in this?

According to the bulletin linked in the second post of The Complete M272 Engine Thread

"When replacing the balance shaft on engine M272, the counterweight must also be replaced. The balance shaft and counter weight are specific to engine designation. Order individual parts and kits specifically to a VIN number."

which would imply that if the parts are ordered according to the VIN, there's no problem.

 

[Neil Richards]

Thanks st13phil. I have decided to go ahead and get it sorted, visiting MBtech at warrington tomorrow.