Ticky-Ticky-Ticky, not Tick-Tick-Tick - PeachParts Mercedes-Benz Forum

landev · #1 11-03-2010, 11:00 AM

Hi all,

I've noticed a new noise on the beloved '96 E300D. The noise is a 2 syllable ticking coming from under the hood at idle. The noise seemed to be intermittent at first, but I'm hearing it more often now. It cannot be heard unless you stand in front of the car (not from the rear, sides, or inside.)

Before opening the hood, I though it must be attributed to one of the accessories run by the belt, but upon further inspection (after changing the oil this weekend) it seems that the noise is coming directly from under the intake manifold (in the vicinity of the injectors.)

I'm guessing this is an injector complaining, but didn't want to go through the fuss of removing the manifold until I had some input.

There seems to be no noticeable change in how the car runs. I did however notice when I changed the oil that there seemed to be some oil (or diesel) on the pan. There's very little oil on the pan... not enough to even drip on the belly plastic, so where ever it's coming from , it is a very minor leak.

The noise is somewhat similar to the noise you might hear with a loose spark plug... kind of a compression-loss ticking.

If this is an injector replacement fix, I have a couple of questions... first, are rebuilt injectors acceptable? Also, in replacing an injector, is it best just to change them all at the same time?

Thanks in advance for the input.

-l-

spark3542 · #2 11-03-2010, 12:57 PM

The injectors are not below the IM, they are right on top of the valve cover.

Maybe a glowplug. I had the extra tick and even a chuff when I had not torqued down a GP all the way. (Anyone who's changed a gp on a 606 will understand the apprehension in not overtorquing a gp.)

Diesel911 · #3 11-03-2010, 04:37 PM

With your suspected Diesel Leak onto the Belly Pan I am thinking the Fuel Injection Pump O-rings might be leaking.
Next thoughts would be the Hydraulic Valve Lifters ticking or the Vacuum Pump.

Harbor Freight sells cheap Mechanics Stethoscopes or I use a 3 foot piece of Broom Stick Handle with an Ear on one end and opposite end making contact with what I want to listen to. Watch out for Hot and Moving Parts and find out where the Noise is coming from before picking something to fix.

landev · #4 11-04-2010, 10:50 AM

Thanks for the replies Mark and 911! The sound does indeed sound like a leak around a glow plug, but I torqued the plugs to spec when I changed them out a couple of years ago (boy was that a fun experience!)

I tried my stethoscope on the noise, but was unable to get down to where it was coming from. What I found interesting though was, as soon as I put the ends in my ears, the noise became alot more noticable (without even touching the car.) I suspect the stethoscope cut out all the lower frequency noise and only higher frequency sounds were then more noticeable.

I also tried a long screwdriver as a listening device, but there's so much stuff in the way that, by the time I got under the manifold, I was in contact with lots of other stuff, so couldn't discern where the noise was coming from .

I guess I'll just have to dig into it this weekend and see what the rub is.

Thanks for your help!

-l-

pimpernell · #5 11-04-2010, 11:23 AM

Quote:

Originally Posted by landev

Thanks for the replies Mark and 911! The sound does indeed sound like a leak around a glow plug, but I torqued the plugs to spec when I changed them out a couple of years ago (boy was that a fun experience!)

I tried my stethoscope on the noise, but was unable to get down to where it was coming from. What I found interesting though was, as soon as I put the ends in my ears, the noise became alot more noticable (without even touching the car.) I suspect the stethoscope cut out all the lower frequency noise and only higher frequency sounds were then more noticeable.

I also tried a long screwdriver as a listening device, but there's so much stuff in the way that, by the time I got under the manifold, I was in contact with lots of other stuff, so couldn't discern where the noise was coming from .

I guess I'll just have to dig into it this weekend and see what the rub is.

Thanks for your help!

-l-

You might want to take a look at the serpentine belt tensioner shock. I had a similar sound, and finally determined it was coming from the top shock mount. Mine was most noticeable at idle, and would disappear when you revved the engine. Pain in the rear to replace, but once done, the noise was gone. Hope you is as simple a fix.

landev · #6 11-07-2010, 01:31 PM

Pimpernell! I pressed hard on the engine shock absorber and 90% of the racket coming from the engine has disappeared. I can't tell for sure if this accounts for all the noise I'm hearing, but I will replace the shock first, then go from there. I suppose the glaze of oil on the bottom or the pan may have been coming from a weep at the crush washer... I'll investigate further and keep you posted.

Thanks!!!

-l-

landev · #7 11-13-2010, 06:47 PM

OK... I thought it would be a fairly simple job to replace the belt tensioner shock. When will I ever learn?

Anyone have tips to getting the bottom bolt out of that shock? What all needs to be removed to get the bugger out?

Thanks!

-l-

landev · #8 11-15-2010, 04:03 PM

Well, Pimpernell, you had the noise down. Replacing the belt tensioner shock seems to have taken care of my noise issue. I'm really amazed, as the noise sure sounded like it was coming from below the intake manifold.

I tried your method for removal of the lower bolt (i.e. pliers, screw driver, and a lot of patience. Frankly I don't know how you managed to get that damned bolt out! I fooled with mine for several hours (after looking at the manual and deciding I didn't want to buy the special tool that I would probably use only once!) I couldn't get a Dremel onto the bolt head, so filed it down to ~ 4mm... still couldn't get it out.

After about 4 hours, I decided to push the bolt out as far as it would go, then took a sabre style hacksaw to the bolt. This shortened it ~ 7mm, but it still has enough about 8mm of thread, and attached the shock to the engine just fine.

Noise gone!

This should be such a simple part replacement... why MB engineers decided to make it so difficult baffles me. To have to remove the fan shroud, fan, fan clutch, and belt (as described in the Star manual) just to get a bolt out (rather than making the bolt shorter, or putting an access hole in the belt pulley) sure seems a bit like poor planning.

Anyway, thanks all for your guidance!

-l-

Alastair · #9 11-15-2010, 04:53 PM

Hydraulic followers....?

They can go tic-ca, tic-ca, tic-ca.....

My ole 190D 2.5 used to do that with some grades of oil. Try changing the oil and filter, maybe even an oil-system flush....