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So i was driving around tonight and noticed that the car wasnt sounding so great under acceleration. It had been sitting out in the cold for a while, so the engine was still warming up and this is the first time ive had it out in cold weather this year (below 40).
Basically the noise sounds like someone tapping their finger on metal. Its a steady click click click click click click click. The click does not vary with the RPMS, it is constant and not very lound. I'm also getting the feeling that my CATs are going bad, i get a vibration that sounds like a metalic vibration between 2000 and 2500 rpms, but at no other time. So im probably going to be replacing them with racing cats sometime soon. I remember hearing they were cheaper (around $150), anyone have a link?
Guys, my car is in shambles, i havent washed in in 2 or 3 months, this is so wierd for me. Guess what i'll be doing over thanksgiving Zaino all the way. Last year i handwashed the thing while it was snowing over the break(only lightly though). Man, i miss working on the car, why does school have to be such a bully for time Maybe ill fabricate an intake over Christmas to bide my time, also, i found a guy who can refurbish wheels for about $60 a piece, so i think im going to do that instead of getting new ones. Ill post pics when its finished (late december, christmas present).
This may sound stupid but a few weeks ago I thought my car had developed a strange noise when cold at idle in drive and reverse. It almost sounded like metal on metal. Once on the gas out of idle I could not hear it and did not hear it in Park. Then I started noticing it in Park, all of time. Once I noticed it in park I was able to look under the hood with the car running. Because of my twitchy idle (may need motor mounts) the plastic cover was rubbing up against the intake manifold causing a sound I would not expect from plastic touching metal. If you are standing looking at the car it was the back left of the cover that was touching. I could not get it situated to stop rubbing, so I took it off. I hope that this may be your problem but I doubt that it is that easy, but I had to mention it just in case.
i think i "might" have the same clicking noise that u may have.... try sitting in ur car... with ur car on and have the air vents blowing something hot/cold/air jsut as long as it's on and blowing something.... u should hear the noise... then turn it off... and see if the noise is still there....
then if the above applies to u... open up the engine bay... facing the car, look down and behind the rad there should be a hose black pretty thick... i say 1" diameter... and see if the clicking sound syncronizes with that hose... casue when i hear the noise i also see the hose moving... thats the most i know about this strange noise... and i'm currently away from the car for about a month so ya... hope u finds out what that noise is...
Guys, my car is in shambles, i havent washed in in 2 or 3 months, this is so wierd for me. Guess what i'll be doing over thanksgiving Zaino all the way. Maybe ill fabricate an intake over Christmas to bide my time
Make sure you spend some time with your family too - they'd probably like that it's sad to be tucked away in a garage all thanksgiving when you've got lots of family around to hang out with. enjoy the car too though some.
King320 those symptoms you describe are exactly the same as I had on my CLK320 earlier in the year. Turned out the cat had gone and the MB dealer kindly put a new one on and mugged me for £800.
Wish I'd have gone for a hi-flow cat as had one on my Corrado VR6 (SLC) and it released a few more HP or certainly made it feel like it.
i think i "might" have the same clicking noise that u may have.... try sitting in ur car... with ur car on and have the air vents blowing something hot/cold/air jsut as long as it's on and blowing something.... u should hear the noise... then turn it off... and see if the noise is still there....
then if the above applies to u... open up the engine bay... facing the car, look down and behind the rad there should be a hose black pretty thick... i say 1" diameter... and see if the clicking sound syncronizes with that hose... casue when i hear the noise i also see the hose moving... thats the most i know about this strange noise... and i'm currently away from the car for about a month so ya... hope u finds out what that noise is...
The noise you describe is coming from the coolant mixing valve located close to the firewall of the engine bay, these valves are used to regulate temp for the climate control system. Had this problem on 2 W208's.
Hello everyone, I have a 1999 CLK Cab, LOVE the car... restored it to 100% to MBZ standards and specs. However, lately when I turn the car on, in the morning, I hear a loud knocking noise from the engine... then after the car is warmed up the noise goes away. It still has full power and everything works. What could be wrong? Thanks
Hello everyone, I have a 1999 CLK Cab, LOVE the car... restored it to 100% to MBZ standards and specs. However, lately when I turn the car on, in the morning, I hear a loud knocking noise from the engine... then after the car is warmed up the noise goes away. It still has full power and everything works. What could be wrong? Thanks
The term "engine knock" means a lot of things to different people. In your case, I'm going to guess it's probably the purge valve.
What's the purge valve? The non technical answer is - a black circular thing, about 2" in diameter, towards the front drivers side of the engine bay, by the ABS box. It has a couple of wires, a couple of tubes and has the word MOT on it.
I recommend you find it while the car is running normally. Then, the next time you hear the knock, touch the purge valve and see if you can feel it pulsing in synch with the knocking sound. If so, that's the problem. Some have tried insulating the valve, while others have been satisfied with just knowing it's occasionally loud and that it may or may not fail.
If you disconnect the purge valve and the noise stops, then you 100% have identified the problem. The downside to that approach is the ECU will turn the check engine light on. The code is a P0412. If plugged in again, the code can be cleared with a code reader. I believe the CE light will turn off on its own after enough time has passed.
Hello MarcusF, thank you for your reply.... I have to tell you this knocking started after I did an oil and filter change. The guy overfilled the oil, next day he took some out. I don't know if this something to do with it. Thanks, Ross
Since I don't believe in coincidence, is this the same type of oil you've always used in this car (brand and weight)? Same filter manufacturer? When you check the oil, where on the dipstick is it?
Overfilled oil will aerate. Aerated oil doesn't lubricate properly and it will cause bearing knock (while it is aerated). However aerated doesn't get better as the car warms up, so I doubt the oil is aerated. Sounds more like a lifter is bleeding down and has to be pumped back up.
Hi MarcusF, thank you so much for your replies!! The noise has been gone for over a week and it works just fine... This happened again, where the noise came and then it went away... I think it is aerated, I drove the car for over a year and it never did that. How do get rid of the "aerated" status? Ross
Like most other crankshafts (flat cranks being the exception), it has counterweights. The red arrows point to the counterweights. If the oil level is too high, those counterweights can splash in the oil. When a crankshaft counterweight splashes into oil, it causes air to mix in with the oil. Like beating a scrambled egg – there are then air bubbles in the oil. Aerated oil is when “air” is in the oil. That's why aerated is pronounced "air rated". Normally, oil doesn’t compress. Once air is mixed in, the air in the oil can compress. This aerated, compressible oil doesn’t lubricate parts like normal, uncompressible oil, and you’ll hear things like rod knock and lifters that won’t pump up. Once aerated, the air will leave the oil on its own. I’ve never timed it, but with the car turned off, in 10 minutes the oil should be completely back to normal.
Hello, the noise is back.... I changed the oil filter and he noise came back. How would I get the air out of the oil? Will an oil change take care of the problem. Should I add Lucas product to the oil to cut the noise? Thanks everyone!
Not sure about Mercedes, but other car brands have had problems with start up knocking caused by piston slap, also it could be from lifters valve lash and variable valve timing drive as well as timing chain. Like someone said knocking means different things to different people. It could also be motor mounts, or a shield that got bent or ? We can't hear it so its hard to guess on here.
11-18-2005, 02:16 AM
Zaino all the way. Last year i handwashed the thing while it was snowing over the break(only lightly though). Man, i miss working on the car, why does school have to be such a bully for time 
Maybe ill fabricate an intake over Christmas to bide my time, also, i found a guy who can refurbish wheels for about $60 a piece, so i think im going to do that instead of getting new ones. Ill post pics when its finished (late december, christmas present).
