Hi all

I've got a meticulously maintained 1994 E320 Coupe Starmark at 85,000 miles- my pride and joy.

In the morning there is a consistent "metallic tapping"/ "metallic clicking" noise that occurs for about 5-10 seconds upon intial start up of the motor.

It appears to be originating internally from the top of the motor back toward the firewall. The noise has been difficult to source as it only occurs for a short period with a cold motor.

I'd really appreciate help with any ideas on possible causes.

Factory authorized service has already replaced all 24 valves once, all 24 lifters twice, inspected cam, air pump, replaced belt and belt tensioner, exhaust system inspected, cam freeze plugs inspected for leaks,and listened with a stethscope all around externally for sources of the tapping/ clicking noise. Oil pressure observed via instrument cluster, appears to be acting normally.

The motor has had religious 3000 mile or less oil changes since I've owned it at 60K, and I'm running 20-50W dino Penzoil. No engine flushes since I've owned it.

Thanks
-fad

Stay after them and demand that they get to the bottom of it. You paid an absolute premium price for Starmark for this very reason. They owe this to you, period, end of story.

Hang in there and good luck,

My Car is a 92 300Ce M104 24 Valve 3.0 Litre engine. it does the same thing. a click click click on startup for about 5 - 10 seconds.

I havent had it looked at, but I posted about it in another post someone posted that was about M104 timing chain. i asked about this in that message thinking it might be timing chain related, but the response to me was that the oil just wasn't on the lifters for the first few seconds during startup.

I hope you find out what it is exactly. I will call my mechanic on friday and see what he says when I describe it to him.

Alon

__________________
'92 300CE - Sold
2004 C240 - 744 - C7 Wheels - Android Radio
2002 C320 - 816 - Sport Wagon

If the lifters have been replaced, I would tend to think that something is blocking your oil gallery that provides oil to one of the lifters.

Thanks Larry, Alon, & Q for your insight and prompt responses.

Well,,,I've agreed to pick up the car this afternoon- unresolved- with credible assurances from our Shop Foreman that he'll continue to research possible causes by tabling the case within his regional meeting roundtable, Monday and get back to me.

I did bring up the timing chain/tensioner as a possible source/cause and he responded verifying with his observation that the clatter appears to be coming from the back-firewall area, reducing the possibility of this being the culprit (non-proximity).

Q- the hydraulic issue (oil galleries/ passages, oil filter/ by-pass valve, etc.) was raised and kicked around in light discussion also, but there does not appear to be a test to verify that this is the failure or cause (beyond replacing parts at random or tearing the engine apart?- - & I'm told this is not a real option).

The shop foreman also proposed this explanation: in his experience that some diesel's have similar design lifters and that this condition is "par for the course" on these diesels (remedied with by revving to 4000+rpm at initial start up for a few moments).

I'm curious if 85,000+ mile M104's with these lifters are exhibiting similar unresolvable tapping/ clicking/ chatter in mass?

I'll keep us all posted.
-fad

fad I also have the E320 with 97k miles and I do not hear anykind of tapping/metallic noise during start up.
engatwork
'95 E320
'97 Honda CRV

This tapping/clicking sound is apparently a normal occurence in cold weather. It happens for a few seconds until oil flows, then it stops.

In my 89 260E it happens for only about 2 seconds, only in the winter, and only if the car has been sitting for a day or more.

Eric Silver

"remedied with by revving to 4000+rpm at initial start up for a few moments"

I would not advise revving a cold, oil-starved engine. If it makes you feel better, my W126 does this on occasion too.

Try to use thinner oil, such as 5w-30, to see if the problem goes away. I think the oil filter is leaking oil back to the oil pan after the engine is off. When you start the engine, it will take seconds to fill up the oil filter before oil reaching the lifters. I do not know much about the gasoline engine. I wonder if there is a one way valve to prevent the oil going back to the oil pan or not. Please let us know what happen if you fix the problem.

David

There should be no "PAR FOR THE COURSE" for your car. Something is wrong. They just haven't figured it out yet. A couple of obscure thoughts come to mind. I still wouldn't entirely rule out the possibility of a oil starved lifter. There could possibly be a damaged or loose rocker shaft cap (not likely, but possible) at that end of the engine. Also, I have seen one case of a valve seat insert not being fully seated in the head causing the valve clearance on that valve to be excessive. Lifter was able to make up the difference, but it took a little longer than usual. This was a Mitsubishi inline 4 cyl. Something is causing this noise. If it were par for the course, why haven't the other 23 valves, etc. heard about it??

__________________
Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.

Jeff,

Since you bring up the Mitsubishi noise problem here, let me tell you what I know. One of the TSB from Mitsubishi stated that the tapping noise was caused by air trapped inside the lifter. The TSB provided procedures for the tech to get rid of the air. I do not think the air pocket is the cause here.

David

Here's the latest:

Our MB Factory Authorized Service- Shop Foreman has spoken to 4 technical specialists at his regional meeting and has passed me this information:

+3 of the 4 technical specialists have indicated that this condition is normal.

+1 of the 4 technical specialists suggests using General Motors Top End Cleaner (in motor oil) since condition may be caused by a piece of carbon stuck somewhere.

hmm....I recall reading a few posts here about resolving carbon issues in a 500E and will review to see if this E320 case may be similar.

-fad