My 2000 E55 has had the normal ticking noise from the lifters, but just recently a knock started. It speeds up when the engine rpms increase, but once the motor has warmed up it goes away. Took it to the dealership and the service adviser told me the shop foreman said to have the injectors cleaned. I said OK to that since the car has 105K miles. Service adviser called today and said knock is still there and the shop foreman now says the lifters need to be changed to the tune of $1,686 dollars. I asked why the foreman said the injectors need to be cleaned and now the lifters need to be changed. Was told injector cleaning will remove carbon build up which causes engine knocking and since that did not remedy the knock, the next step is the change the lifters.

I would appreciate feed back on what dealership is saying needs to be done and the cost to replace the lifters. Thanks.

 

If your NA 55 knocks at idle (like many M113s), dirty injectors were never the cause.

I changed my lifters as a DIY project. It’s time consuming (took me 4 to 6 hours including trips to the hardware store), but a straightforward job. In my case, changing the lifters caused it to run quieter. Don’t be surprised if you get a call about a couple of vacuum hoses after they’ve started work. The hoses harden and will crack with age. For a DIY person, hoses are very inexpensive. I envision preformed hoses directly from the dealer to be a bit more pricey.

 

I went to an in dependent repair shop and owner said it sounds like timing chain tensioner issues. He is keeping car overnight to start when cold. He said if timing chain issue then a lot less expensive than replacing lifters.