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2012 C300 Sport 4MATIC
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Discussion Starter #1
For the past couple weeks, my 98 ML320 has sometimes been making a slight ticking noise under the hood on cold start. It's possible it's been happening longer and I didn't notice. It's been brutally hot and humid here lately, so I've been putting the windows down after starting up the car. The noise isn't loud enough to be heard with the windows up. It will go away on it's own after maybe 30 seconds to a minute, and if I give the car a little gas, it goes away instantly. It doesn't happen on every cold start.

Also for the past couple weeks, I've felt like the car has been running a bit hotter when I idle. It typically runs a hair above 80, but lately I've noticed it go as high as the half way mark between 80 and 100, or even slightly higher. It goes back down as soon as I start moving again. I just kinda chalked this up to the weather, until I started noticing the ticking as well.

Am I just being overly concerned here (historically that's been the case), or is it possible there's some sort of issue going on? Other than these two things, everything else with the car has been status quo. Thanks.
 

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I don't think that you are being overly concerned. I think that you are just seeing the car age. You didn't say what the mileage is nor did you discuss service history. I'm assuming over 100K and that you have kept service as required. My guess on the ticking noise is that the valve lifters are getting sticky and just showing their age. I understand your worry but tell us more about the service history - oil changes, coolant changes, etc.
 

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1998 ML320
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613 Posts
On my 98 I ran across two ticking noises both which seemed to stop when above idle. The first one was definitely a sticky lifter. I don't know if the cause was it just sitting too long on a dealers lot before I bought it or a slight sludge problem. After driving it for about a week or so it quieted down and has now stopped. So it may have just needed the oil to clean and lube the lifter a bit. That noise was more of a tick and distinctly to the side of the engine in my case drive side front of the engine.

The other noise is in the middle of the engine and it seems like a lot of guys are seeing this one even in 430's. This noise sounds more like a rattle ball bearing sound. I though it was my idler pulley at first. Others have thought timing chain or the chain tensioner . This noise comes back on mine at idle consistently. There is a video on YouTube that you can clearly hear the noise. It is on a 430 and is much louder than my 320. Oeschj said his 430 was that loud. He just seafoamed the oil and changed it and that helped but then he did the down the intake smoke out the block and that he was saying got rid of it. No more noise. I have no idea why the intake being seafoamed would have stopped his noise. I can see it being oil pressure or wear related.

Anyway your not the only one with this. If you search you'll find guys changing chains and tensioners and still having the noise. Never used sea foam before but I'm going to try it out on mine, just not comfortable on the smoke machine way of application :D
 

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2000 ML430 (Sold)
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Never used sea foam before but I'm going to try it out on mine, just not comfortable on the smoke machine way of application :D
Says he who beats his ML with a hammer on a daily basis.....;)


dustindustrial, does the noise start after the Secondary Air Pump shuts off, and the truck has slowed its rpms down to idle speed (500ish)? or immediately on start-up?
 

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1998 ML320
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You thinking the description could be the purge valve on the firewall? I forgot how loud mine was. It somehow settled down as well.

I do not beat it with a hammer. I prefer to think of it as attitude adjustment... Lots of things a hammer can be used for, opening windows, applying wax, turning things off
 

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2002 ML55 AMG, 2005 Chrysler Crossfire Coupe Limited, 1999 C280
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This may not necessarily be YOUR solution; but when my ML55 starts to tick it is always indicative of the need for an engine oil change.
 

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1998 ML320
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Curious FAR at if when you tick your sound is localized ie sounds like one lifter or do you get the more than one source? Does it just start up or fade in over time? When I was trying to figure out what was making the noise I found a lot of guys also looking for noises or at least what was causing them.
 

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2000 ML430 (Sold)
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Ticking is a good sign. If its ticking, its still alive. Its when it stops you need to get it checked. Or call the coroner........


Sent from my GT-I9000M using AutoGuide.Com Free App
 

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2002 ML55 AMG, 2005 Chrysler Crossfire Coupe Limited, 1999 C280
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Curious FAR at if when you tick your sound is localized ie sounds like one lifter or do you get the more than one source? Does it just start up or fade in over time? When I was trying to figure out what was making the noise I found a lot of guys also looking for noises or at least what was causing them.
Good question Wragie!

The sound always seemed to come from one lifter or at least generally from one location around the engine.

It was always on startup and a few minutes after; the sound would slowly dissipate as engine became warmer.

As I said earlier, an engine oil change plus filter would always 'solve' it for me.
 

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1998 ML320
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Really does sound like a sticky or varnished lifter that slowly pumps up doesn't it. Mine was driver side near the front. Wonder if this is a hot spot in the engines or just farthest point from oil pump or lowest pressure in oil system. I did look at replacing the lifter/lifters (just in case) right before I bought mine. Was very shocked to see the lifters priced down around $10 each. If the bores are not the problem just the lifter, then it really wouldn't be that bad a job to replace the lifters. Well maybe not that bad, if you can do this through the valve covers it might not be.
 

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1998 ML320
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Ticking is a good sign. If its ticking, its still alive. Its when it stops you need to get it checked. Or call the coroner........

I thought yours stopped ticking? Should we call 911 or SCAA or just send a liter of Mobil and some flowers made out of microfiber? :D

(That will teach me to speed read, miss all sorts of things.. LOL)
 

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2000 ML430 (Sold)
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Oh believe me. It was when mine stopped ticking that i did all the checking. I wanted to know what the hell made it stop finally!
The result was too much KFC going through the intake ;)
 
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