190E Engine Noise

93' 190E 2.3 Automatic
It has this tapping rapping not quite a knock sound, except when you're starting it, it's sounds terrible when it's being cranked.
Then after it starts it runs fine except for the tapping, it's louder than just a tick tick like a tappet, but it's not a real heavy metal to metal thunk thunk either, except when cranking to start.
The thing about it is, if the engine is under a load, accelerating or if you brake and run the engine up over 1.1k or 1.2k, the noise just goes away, or at least is almost undetectable. It is noticable at idle, louder when decelerating, and loudest when cranking to start.
I've had it to the MB Master Tech. Had the bottom end checked, put in new rod bearings. Didn't help. Everything else looked fine. Compression test and leak down were good. Had the oil analyzed for metal particles, it seemed fine. It doesn't miss or anything. It doesn't use much oil or water, a little but nothing out of the ordinary for a 14 year old car. It runs fine, except the noise.
To me it sounds like it's right in the middle of the engine at cylinder # 3, but I'm no tech.
This thing has people stumped all over the east coast, and no one wants to say for sure what it is. Of course they won't mind charging to take the engine apart and start replacing things until they get it right, but I'd like someone to know for sure what it is BEFORE they start into it.
Any thoughts on this ???
Thx
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It is definitely in the valvetrain... Camshaft lobe worn down or hydraulic lifter is worn or the pil supply tubes to the hydraulic lifters is clogged.
I'd suggest you run synthetic oil to see if it alleviate the symptom. When you first switch over to synthetic, engine will sound worse at idle... do not be alarmed... just drive it around town and then listen again... It should gradually get better as you drive.
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miles, it did sound worse, and it didn't get any better. And with the thinner oil it does tend to use a little more oil. Rings/ valve seals (??). But if I step up a grade thicker it's just thick enough to stop the oil usage. So there is some wear in there, but it doesn't seem to be critical just yet.
Just thinking, but if a lifter was stuck or a lobe was worn, wouldn't there be a miss in the engine?
Thx
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No... there won't be a miss unless it is in really bad shape. I am willing so bet it is the camshaft... We had 190E 2.3 also and the cam was worn at #1... pretty bad.
Just take off the valve cover and you can physically see the wear.
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Cam lobe, camshaft support bearing, also, while the top is open, I'd check the timing chain and its hydraulic tensioner if nothing found on the cam's lobes and support bearing.
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the noise you describe is a hydraulic valve lifter.I have had my 190e for over nine years.and have changed the lifters or tappets another name same thing.a few times they are very cheap,and easy to replace.its strange but you dont get a misfire.because it still opens the valve somtimes they go quite and when they lose a bit of oil they tap.its not worth changing one i would do the lot if you remove the old ones and push a stiff piece of wire in the hole at the top of the tap pit if there is no resistance it no good when fitting new ones prime with engine oil pushing down with a stiff wire on the ball valve in the tappit hope this helps fran
"EVO-X" wrote
> 93' 190E 2.3 Automatic > > It has this tapping rapping not quite a knock sound, except > when you're > starting it, it's sounds terrible when it's being cranked. > Then after it starts it runs fine except for the tapping, it's > louder than > just a tick tick like a tappet, but it's not a real heavy > metal to metal > thunk thunk either, except when cranking to start. > > The thing about it is, if the engine is under a load, > accelerating or if you > brake and run the engine up over 1.1k or 1.2k, the noise just > goes away, or > at least is almost undetectable. It is noticable at idle, > louder when > decelerating, and loudest when cranking to start. > > I've had it to the MB Master Tech. Had the bottom end checked, > put in new > rod bearings. Didn't help. Everything else looked fine. > Compression test and > leak down were good. Had the oil analyzed for metal particles, > it seemed > fine. It doesn't miss or anything. It doesn't use much oil or > water, a > little but nothing out of the ordinary for a 14 year old car. > It runs fine, > except the noise. > > To me it sounds like it's right in the middle of the engine at > cylinder # 3, > but I'm no tech. > > This thing has people stumped all over the east coast, and no > one wants to > say for sure what it is. Of course they won't mind charging to > take the > engine apart and start replacing things until they get it > right, but I'd > like someone to know for sure what it is BEFORE they start > into it. > > Any thoughts on this ??? > > Thx
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I would say camshaft,cause a friend of mine have a 1993 190 too and got the same problem a couple of years ago,he got the suggestion to get a new one from a mechanic at the MB Garage. It helped it sounded like a new car after the change. Regards

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