Hey guys... hope this isn't something horrid to admit, but I've got a 2005 Crossfire, not a 'true' Merc (was going to get a 320SLK, but the Crossfire had lower mileage!). As many of you probably know, it has the M112 3.2 V6 in it, and most every other component in the car is Mercedes as well.

Anyway!

The car has 22,000 KM's on it - I'm Canadian, sorry, I'm not sure what that is in miles, but it's very (very) low. Car was well taken care of by previous owner, it seems. Everything is in great shape - I'd say an easy 'A' if I were grading it. The only real problem is this damn ticking from the engine...

At first, I swore it was a collapsed lifter. The car had been sitting for so much of its life (a seven year old car with 22,000 KM's is crazy-low) that I assumed that a lifter (or multiple lifters) seized because of sitting around idle so much. The mechanic that I took it to (Chrysler dealer... ugh) replaced the lifters, since they thought that the problem too. I know, I know - dealers are bad. I'm very good mechanically, but I mostly work with 'old tech' engines, and I have a third-party warranty that's really only good at major dealerships, so I didn't have a choice.

Anyway, the lifters are replaced... engine still ticks, and it also has a miss at idle - both problems existed before the replacement, and still do afterwards, so obviously the lifters are NOT causing the problem. The noise is noticeable regardless of whether the engine is cold or warm. The ticking seems to 'peak' in frequency and volume just shy of 3000 RPM's, and either from overall engine noise or just speed, is hard to hear afterwards. The miss happens mostly when the car is warmed up.

So... any ideas? I've got a link to a video, here, of the engine idling - any ideas appreciated. The frequency of the sound does go up and down with the revs, by the way. My only other guess was exhaust manifold gaskets, but the mechanics swear that they are fine (and any mechanic should be able to tell that much).


Thanks for any guesses.

 

sounds to me like the exhaust manifold. Ive replaced 2 on the SLKs actually in the past also i would just check the connection of the exhaust pipe to the manifold. i could have told you that that sound is definately not a lifter.

 

My main guess as well; I could have SWORN it was a manifold, but the dealer mechanic keeps saying no. I'm probably going to go to a respected Mercedes mechanic (they like the car, which is good!), and see if they can sort it out.

Thanks for the tip, by the way!

If anyone else has any guesses, by any chance, they're also welcome, but I'm betting manifolds as well... that said, I've never heard of an exhaust manifold leak that caused a car to miss at idle, so I think I'm chasing two different problems, here.

 

i guess it could be a manifold gasket leaking. try spraying some brake clean or 2+2 at the manifold gasket area and see if the noise goes away . it should not be causing a miss. usually if 112 engine is missing, its usually bad wires.