problem w/ e500 need advice - PeachParts Mercedes-Benz Forum

#1 05-11-2002, 12:29 PM

haven't been here in a while and general lurker in need of help. 94 e500 w/78k miles. had since 53k miles and this is first potentially serious problem. about four weeks ago, started hearing a ticking sound just like a very loud watch. the number of ticks per minute is proportional to engine speed. it appears to be coming from the front of the engine but can't isolate which side. when i took it to dealer yesterday, it wasn't ticking but dealer says belt tensioner making noise. dealer says belt tensioner is bad and it and pulley should be replaced. says heard ticking today and believes it to be lifters and /or oil tubes. says may need to replace tubes, tappets, etc. wants to open it up and if see broken?/plugged? tubes then replace tubes. but that might not cure it and won't know unless button it up and see. also said might be a good time to replace chain rails as long as we are in there. next, check engine light had been coming on, but then going off for approximately 8-10 weeks. it hasn't been on for the past week or two so it and the tick didn't seem to be directly correlated. fault codes stored include engine misfire. any advice or thoughts on this matter greatly appreciated. being told i'm looking at up to $3000 depending on what they "find." HELP!!!
steve kotler
coral gables, fl

Glen · #2 05-11-2002, 03:32 PM

I'm not sure what advice to give you but I'll relate my experience. Early this year I took my '94 E500 in to my local MB dealer for what I thought was timing chain rattle. The noise only occurred at warm 'low' idle, that is, only with the car in gear idling about 500 RPM. In park, with idle at 650 to 700 RPM the rattle would disappear. With approx. 90K miles, I assumed it was time for a timing chain replacement.

On first inspection, the dealer determined the problem to be a bearing in the alternator. I was a bit apprehensive, but because they said if that didn't fix the problem I'd end up with a free alternator, I authorized replacement. I think it was around $500 for parts and labor but I reasoned that with 90K miles it might be a good time to do it. If you search the archives here, you'll find that a faulty alternator can cause many seemingly unrelated problems, e.g. stalling, limp-home mode, etc. So, I gambled.

I picked the car up and by the time I got home...7 miles...I heard the tell-tale rattling as I pulled into the garage.

The car went back the very next morning and they diagnosed the problem as a faulty belt tensioner. I wasn't convinced. I pushed and asked them to pull the valve covers and check the chain. The chain and sprockets all looked nearly perfect. But the upper chain guides were showing heat related fatigue...basically, they were very discolored and presumably brittle. I authorized new guides and they pointed out the oil tubes which I also authorized. At the same time, they noticed the wiring harness and recommended replacement. Things were starting to get expensive!

In the end, I authorized the four upper guides, oil tubes, and wiring harness. Remember the new alternator? I talked to my service manager and we worked out a deal. I ended up getting a new belt and tensioner for free plus the wiring harness at cost, no labor. Plus I have a new alternator. In retrospect, I would probably pass on the oil tubes...they are expensive, I think around $15 each x 16. But they are easy to get to so a diy'er could do them with relative ease. I think the total cost was round $3600 most of which was labor for the upper guides.

A note on the timing chain, the senior tech at the dealer talked me out of replacing it. In his opinion, it just wasn't called for at this point. He asked me to come down and look everything over. Indeed, the top end looked really clean, no visible wear that I noticed. So, if well maintained even the long M119 V8 chain will hold up. I had read so many stories of these chains needing replacement and/or breaking at the 90K to 100K mile mark, I was a little paranoid. I now have more faith in the engineers who designed this engine.

#3 05-14-2002, 12:24 AM

looks like new tubes and guides for me too. also advised to replace caps and rotors as they show severe arcing. i did the wiring harness 6 months ago. have also been through 3 ps pumps in 3 years. thanks for the reply.

Michael · #4 05-14-2002, 07:03 AM

Ouch on the PS pump! I'm on my first (knock on Burl) but plan to re-seal it soon as it's weeping fluid a bit.

Do you change your PS fluid? Any other reason you can think of as to why you're burning thru those PS pumps?

As to the main thread here, I think you should try to get it in front of a big0time experienced tech before you start throwing money at it. Good luck.