Hi everyone
My car has been making a soft ticking sound for a good while now. It's coming from the passenger side of the engine, here's a video where I tried to capture it:
The sound gradually builds as the car gets up to operating temp. - when it's cold, it doesn't appear to make the noise. I have already replaced the hydraulic cam followers on the passenger side, that didn't help. I can also rule out the auxiliary belt system as all the components there are new and I've run the engine with the belt off and it still made the noise.
I suspect that the exhaust manifold on the right side might be going out - these have a double-walled construction and I've read multiple reports on German forums of the innards breaking on the V6 (M112) models especially, which leads to noises described as similar to the one I'm getting. Unfortunately, I have not found a decent quality audio/video recording of a confirmed case so I'm not quite yet willing to drop $500 on a new manifold just on a hunch. I bought a set of used manifolds (described as "perfect" in the ad, of course) and when I got them the passenger side manifold made a distinct rattle when tapped with a finger (the driver side one is perfect, of course... figures!) so I don't wanna install that either.

Is there anything else that could be making such a noise or should I try my luck with another used manifold?

Thanks in advance for your help!

 

 

Well, like I said I've already replaced (most of) the lifters on that side, so I really doubt that's what's going on here... I say most of because I'd ordered a full set but they sent me a few wrong ones, so I just focused on the ones to the rear of the engine where the noise appears to be coming from. I've also heard the lifters clacking before after letting the car sit for a month or so, that sounded entirely different - much more metallic and harsh than the soft ticking I'm getting now. I've pretty much convinced myself the problem is likely a cracked/loose exhaust manifold interior - I've ordered two more used passenger side manifolds, hopefully one of them won't have any rattles. Here's the set I already have - the video should make clear why I don't want to install the passenger (right) side manifold: There's quite a few stories of these manifolds going bad on M112 and M113 engines - the M112 apparently received two updated designs, but the same doesn't appear to be true for the M113.

The color on my car is code 347, "quartz blue" or "chalcedonblau" in German. It's pretty common on these cars around here from what I can tell.

 

i would cut your losses on that engine and drop in a used/working 55 AMG engine of the same year. thats what i did when i had a lifter tick on my 500 engine. plug and play... you may be able to get $500 back on that engine on ebay, used 55 engines go for about $2000 last i checked. its not hard to rack up $2000 in parts alone on diagnosing valvetrain sounds...

 

Here in Europe, used 55 engines go for closer to $6000... Also, throwing out a well-running engine just to get rid of a minor noise seems like using a sledgehammer to crack a nut.

I'm going to replace the passenger side exhaust manifold with a non-rattling used one tomorrow - we'll see if that fixes my issue.

On another note, the engine has now started to make some lifter noise from the driver's side on cold starts... It goes away after some minutes and some revs, but it's still annoying. Might give it a whole new set of lifters if I find the time, or maybe try out some magic oil additives. But first I want to fix the ticking.

 

looks more like your chains have to be replaced

 

 

Well after replacing the manifold, I can now say with certainty that that was not what was making the noise - the old one was looking perfect and didn't make any noise when tapped.

That places my suspicion back on the valvetrain - I'm still skeptical about this being a lifter because those sound a lot harsher in my experience, but who knows. I was thinking it might be a worn valve guide, which would really suck...

I really don't think this is the chain I'm hearing. The noise is coming from one specific cylinder (I'll have to try and find out which one by finding which injector's noise it's synchronous to) and a chain would make more of a constant rattle.

 

the chain loose makes the valves loose sync

 

don't just throw money at guessing. This item is worth going to the dealer or a true Benz mechanic for a diagnosis. I got a check engine light for secondary air pump. I put it on and I got the same error message. My off brand Benz mechanic charged me $100 for the diagnosis; it was a vacuum line. So check and fix once. As for replacing the engine, That's just comical.

 

whats comical about upgrading a plug and play AMG engine , for about $2500 instead of spending $3000 replacing the valvetrain with all new parts? Some of us aren’t afraid of pulling a Mercedes engine... if he’s replacing lifters I’m sure an engine swap isn’t outside of his scope of capability. Unfortunately for him this isn’t cost effective in his country

back to the thread at hand, that noise is just a noisy injector. I recently installed a reconditioned injector from eBay and it made this same noise, I may get another as the noise also annoys me. I agree that ticking lifters sounds different

 

Thanks for the input! I've been thinking about the injectors as the source of the noise, there's a Spanish seller on eBay selling sets of 8 flow tested injectors for about 150 bucks, I might just go ahead and give those a try. I'm already dreading the wrestling match with the wiring harness on the fuel rail...
Do you think a slightly rough idle (might just be paranoia... but I can feel some vibration through the seat, wheel and especially on the driver's door window "sill") might also be caused by the bad injector?

I think I also have some lifter tick going on on cold starts - it disappears after a few minutes and sounds much more metallic and harsh.

As for the engine swap debate: You're correct that I would think a swap would be doable for me - although I can't do it at home so I have to rent a lift, which can cost quite a bit as I'm not the fastest mechanic in town (engine r/r in my 4cyl Saab ended up taking me about 4-5 12 hour days and cost about a grand just for the shop rent, although I also did a bunch of work on the engine while it was out - all new timing components). But in my opinion, it is a bit of a sin to throw out a nicely running engine just because of a noise - also, with a used AMG engine you really can't know if it's gonna develop an issue at some point without opening it up, which of course puts the cost at about the same as just overhauling the current engine plus the price of the used AMG engine. You do get the added HP as a benefit though of course

 

There are a few more things to take into consideration regarding the AMG swap, i think

m113 engine is known as a super reliable platform. Now the AMG m113 is just that, but hand-built with extra care. I’ve put over 50k miles on my swap and it’s run like a dream. I think if you buy a lower mileage AMG engine, from a car that looks like it was cared for (other than maybe a minor collision) and it’s a win/win situation (at least for people in the US with access to these prices). Not only that but since my engine swap I’m able to get up to 32 mpg! I can provide pics for proof if anyone doesn’t believe it, I know it’s hard for to me to believe my 5.5 v8 from 2002 performs better than most 6 cylinders to this day. My old 500 engine could get mid-20’s mpg but the 55 is just more efficient it seems

in my experience, these engines are not “hit or miss” they are largely reliable besides the occasional noisy lifter issue. So while I would agree otherwise about taking a gamble on a junkyard engine, I say just make sure to do your homework on the donor car, hell maybe even run a carfax report lol.

as for the injector issue-

the problem with these eBay “refurbished injectors” is that while they maybe really clean, and even flow tested. They are not sonically tested. I believe the one refurbished injector I installed is one of my noisy ones unfortunately so I may switch back to my original one. Perhaps these injectors just get noisy after 100k miles and need changed anyways ...

regarding the wiring, it’s really not that bad..if you disconnect the ignition coils and injectors (use a small hooked pick for the injector plugs), you have to disconnect the egr valve plug and the job is fairly straight forward. Save yourself the headache and read my two recent threads about injector pintle caps and o-rings, if your engine has close to 100k miles you need to be super careful while lifting the fuel rail or you may break off a piece of pintle cap into your engine like I did. I spent hours trying to vacuum all debris out of my 8th cylinder as unfortunately when the pintle cap broke off, cylinder 8 was the one with the intake valves open at that time!

Luckily i compression tested afterwards and everything is great. But save yourself some headache and read through my recent threads on the matter

 

Heh, actually that pintle cap thing happened to me also and I ended up just leaving it, figuring that metal is stronger than plastic. Made some scary noises for a few seconds, then it probably got blown out the exhaust valve, now everything seems fine again - fingers crossed...
And yeah, you do have a point on the AMG engines. Did you use the original 500 ECU or did you swap that from the AMG (along with TCM and shifter control unit as those are tied in to the "drive authorization")?

 

The engine runs smooth as butter (well, normally, right now I am tracking down some pesky o2 sensor /vacuum leak issues) and didn’t throw any CEL’s so I never bothered swapping ecu etc

i did swap in an AMG trans, only because I rushed my engine swap and ****ed up the original trans. Figured it was a good excuse to upgrade to an AMG transmission anyways

 

just an update, yesterday i noticed my noisy injector was no longer noisy

today its back again