300D 2.5 TURBO ticking

[detroit442]

Hello Everyone, I've been searching the archives of this and the tech forum for a similar problem I'm having. I bought a '91 300D in January and have been very pleased. However, I began to notice a slight ticking noise after the engine warmed up. I checked the oil and the level was correct. I went ahead and had the service done as it was due soon. After the service (done by a Mercedes shop) the ticking got more severe. Again, cold it hardly ticks at all. I took it to a shop near my house and they said it needed and engine overhaul. The car only has 178,000 miles. Not satified with that answer I took the car back to where I bought it. The tech used a stethescope and localized the noise. To me it sounded like a lifter tick. He said it was the timing chain. I ordered a timing chain and tensioner and hope to install it this week. After reading some of the other post I had a question about the vacuum pump. Would a vacuum pump that is going bad be fairly quiet on start up and then get loud? I'm also going to replace the belt tensioner shock as it is also moving a little more than I would like. Finally, I got hold of the Mercedes timing chain replacement procedure. Is the timing marks easy to see? I appreciate any help y'all can give.