I know this has been discussed before, but I just want to know for sure in my situation what to do. It is a 1987 300E with 154k and when it starts and is cold, the chain makes that thwacking sound until the oil gauge hits 3. That is all i can hear, so based on this and the fact that it is the original chain, should I have it done? Will changing it improve performance/economy? Also, what is a ballpark estimate on cost to do the job?
Much thanks in advance