Making a weird noise on startup. Please help!
 

This happen every so often. Most noticeable when it's hot outside. Sometime it's very loud and will only last about 2-5 sec.

It's been to the dealership twice already and they seem to not know what is causing the tapping/clicking noise. They told me they did every test possible and check everything and it's not showing any problem.

I had a couple recording of the tapping/clicking noise and forwarded to the SA!

The 2nd time, my car was at the dealership they told me they couldn't replicate the noise and kept it for 2 weeks to see if they can replicate the noise. Nothing! Not a single noise they said. But base on the recording I had provided to them , hey told me that they believed it's from the belt tensioner and replace all 3 of them to be proactive.

So I took it home and a couple days later the noise is back ! And I'm back at square 1.

Here is the clip I happen to record it last night


It's going back to the dealer this Monday.

My experience with MB is that they don't diagnose anything other than computer codes. Even though it is an obvious problem they only look at computer codes.

On top of that when it was there for 2 weeks they said they couldn't reproduce the noise. And told me that they was being proactive and think it's the belt tensioner and replace all 3 of them. But when I took it home. It still made the noise.

Here is another clip today

Gas or diesel? Sounds a bit like typical "diesel clatter," though it's supposed to be muted in the 3rd generation MLs.

It's a GAS model V6

That's MB's answer to a lot of stuff. They can't reproduce it. IMO they have the worse service of any brand I have ever purchased. They have gone away from diagnosing a problem to letting the computer do it for them. Sad for a company that had a great reputation.

Mine does this too. I read somewhere, but can't find it now, that this is normal and related to the direct injection. I asked the SA today because I was in anyway and that's what he came back with when he asked the mechanics. He mentioned cold start, which I'm assuming means hasn't been started for a while as opposed to temp. Anyway, I don't know how often it happens because you really only hear it if you start it and jump out to load, etc or someon else starts it while you're outside. That's what I'm told anyway.

It is not normal.
My 2013 ML350 Gas, had the same exact noise.
Started about 3000 miles.
It took them 2 days before they heard the noise (I heard it
almost every time I started and turned off the car).
As soon as they heard they knew what it was. They had
seen this problem before. A known problem.
Timing Chain Tensioner noise.
It them 3 weeks to get the parts, but it is now fixed. No more noise.
They replaced the left and right secondary drive chain tensioners.
It took them 4 days to do the repair, but I was provided with
a loaner car.

Been about a month now and no more noise.
Don't let them tell you it is normal.

Now the car has developed an annoying vibration noise in the
dash. Not sure if this is covered under warranty or not.
Not to impressed with Mercedes quality at this point.

Both Left/Right Secondary Drive Chain Tensioner was also replace on mine on the 2nd visit. But the noise still exist.

Thank you SuPER__S for posting this thread. Where are you located?

My ML500 does it too, and it started about a week or so after it was delivered new. It appears to happen almost everytime on warm startup if the engine has been shut down for at least 10-15 minutes or so. Doesn't seem to be affected by cold/cool or warm/hot weather at all. And like yours it seems to do it for a few seconds then stops, but it doesn't sound very 'Mercedes' like, and I've had a few people look at me strangely from outside. I can't tell if it's doing it on cold startup as the V8 roars very loudly on initial start each day after an overnight rest.

I haven't worried about it too much as my first service is coming up soon and I am going to get them to look at it then. Showing them your video will help alot, and save me from doing the same thing.

I hope your dealer can sort you out soon. I know it's a pain in the butt to keep going in all the time. I hope they at least give you a loan car to drive.

Please keep us informed of the outcome, and I will do the same when the time comes.

Cheers .... :y

Is there any chance that this noise can be from some of the hydraulic lifters clanking until the oil pressure builds up? If there is thin oil in the motor, this can happen. Fairly common problem in many motors.

Any comments on this possibility?

This could be a possibility. I have though about this also but didn't know what type of oil weight they have in it. I think it's 0w20 ?

I live in Texas where it's warm or HOT most of the time. What weight oil should I be using ?

They have break-in oil in there. Not sure what weight it is. But it is pretty thin.

I guess the only way to test this theory is to change to a slightly thicker oil. Kind of a pain in the butt though.

Dropped it off at the dealership today...

The mechanic that has been working on my ML and did the 3 tensioner came out and talked to me to better understand the noise. He was very nice and knowledgeable. He said that another customer came in and is having the same issue. Stated that the video clips I had of my car making that noise helped him a lot.

He told me that the last time my ML was there they replaced all the 3 tenionsor and now there is another updated bulletin advising them to make another updated. Had a long talk with him about all kind of possibility, I will get a better updated on my situation.

Anyways I told him I wanted to let the car sit for a good 30-45min and I wanted him to listen to it.. So once it was sitting for awhile.. He popped the hood and I started the ML and it made that noise and right away he said it's the LEFT CHAIN TENIONSOR.

I'll update as soon as they give me an update.....

Thanks again for keeping us updated. It sounds like your dealer is trying hard to look after you and get your issue sorted.

I have forwarded your 2 Youtube videos to my service advisor to see what they think. Thanks also for doing that, it's saved me the trouble.

I'm not due for my first service for another 168 days but I'm now thinking this is something I should get fixed sooner rather than later.

I'll let you all know what the dealer says as soon as I hear back from them.

Safe driving folks :zoom:

Here is another clip.

To those that have had this ... does it happen every time? And to those pointing to the tensioner, would that problem happen only sometimes? I feel like I've had this noise, but definitely not every time I start. Even after sitting all night, rarely have I heard it. Just trying to gather as much info.

It doesn't do it all the time only after a drive and siting for at least 30mim. It will do it but not all the time.

The loaner 2013 GLK they gave me also a does it but not as much as my ML.

The tech heard the noise on my ML and said it was the left tensioner. But he has already replace all 3 tensioner so I will keep y'all posted.

Great thanks a lot. If I have to take it in, I'd like to have something to point to.

No problem, I would take it in so they can fix it. The more the dealership know that this is a problem the better they can understand it and make a recall on it.

I'm taking mine in tomorrow and I suspect it's going to be there for a few days. As soon as I know any more information I'll keep you all posted ... cheers

Well it's been 3 days and the dealer still has my car. They're scratching their heads a little bit, but fortunately when I dropped it off I spent 15 or so minutes chatting to the service advisor and then we went outside, started my car and the noise occurred. We also had the workshop foreman with us too so he heard it as well. I have also shown them SuPER__S's Youtube videos which has helped too (thanks again SuPER__S!).

It's also getting the passenger window fixed. It was bouncing back down after I pulled the button up & then let it go to close it (auto close). The only way I could get it close completely was to hold the button up until it was fully closed. A few times it was very slow, and was shaking as well as it was trying to close. Other times it worked just fine. Weird. We had this same problem on our C250 when it was new, but oddly it fixed itself!

Plus I have a bad speaker vibration (I've got Harman Kardon) in the driver's' door speaker and rear subwoofer when I play louder/beefier music which they're looking at too.

I expect to have the car back before the weekend, but I'm not holding my breath.

Will keep you informed of any progress re the weird noise at startup.

Cheers folks .... :cheers:

Mine have been at the dealer for over a week now. They are waiting on parts (oil pressure check valve).

I'll update when I hear from my SA.

Got the ML back and everything seem ok so far.

They replaced the Left and Right chain tensioner (AGAIN) and also both upper oil check return valve.

I been driving around town and no noise so far.