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1996 S600
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13 Posts
Discussion Starter #1
Hi,

I am a new W140 owner. I used to have w124 and always wanted W140. I finally got 96' s600 and after a week of owning it I hear this sound. I hope its not a rod knock. My RPMs are also bouncing from 700-800 or so.

It sounds too me that its coming from the driver side throttle body. I had bouncing RPM on my W124 and it was linkage on the TB, but I didnt have this knocking sound.

I also checked pulleys and they look fine.

Any idea?



Thanks!!
 

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Premium Member
'99 S420 119K
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1,510 Posts
Sounds to me like ticking lifters.
 

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1994 S600 Coupe, 1995 S600 Coupe
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2,851 Posts
Ditto. When did you last change oil and filter? What oil is in it? You need at least 5w or 10w -40 synthetic, changed every 5000 miles or so. Smell the oil, and make sure it isn't thinned by gasoline.

Jon
 

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1996 S600
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13 Posts
Discussion Starter #4
I just changed the oil 2 days ago. Used Mobile 1 10w40.

When I bought the car oil was above max, I put it half way between min and Max line. I will add some more.

Does m120 have plastic oiler tubes or does it even have them at all?

If I put more oil and sound goes away is that really a permanent fix it should I do something else?
 

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1994 S600 Coupe, 1995 S600 Coupe
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2,851 Posts
No worries about tubes on the M120. Drive it awhile. It'll probably clear on its own.

Jon
 

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1996 S600
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13 Posts
Discussion Starter #6
Really? A reasonable solution is to wait it out?
I am not trying to argue or anything but I have a internal noise associated with the engine and it sounds too risky to just drive and hope it goes away...
 

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Premium Member
'99 S420 119K
Joined
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1,510 Posts
Really? A reasonable solution is to wait it out?
I am not trying to argue or anything but I have a internal noise associated with the engine and it sounds too risky to just drive and hope it goes away...
A LIFTER is part of the valve train; cam shaft, tappet, lifter. The lifter fills with oil from the oil pump pressure, and softens the blow of the tappet on the valve stem. When you hear a tappet clicking from a collapsed lifter it's because the lifter isn't properly filled with oil, and there could be several reasons for this. This situation is unlikely to kill your engine, but it IS annoying. Worst case scenario, pull out the lifter and replace it with a new one. Not cheap on a V-12.

Without knowing the mileage of your new to you W140, what kind of abuse it may have seen, the service intervals, etc., it's difficult to diagnose EXACTLY what needs to be done to resolve this issue. At this point you have a tick, not a slap, and the engine appears to be running smoothly enough.

The correct advice at this time would be as Jon stated, give it a few miles(100-500 mi) and see if it goes away as the fresh oil MAY resolve this issue. There are several additives on the market to free up sticky lifters. I DO NOT RECOMMEND THESE PRODUCTS. You sound desperate so I mention this for your information. Jon seems to be a very, very capable and knowledgeable MB specialist. I've seen many of his posts, and his advice is always spot on.

How is the oil pressure? Is it cold where you reside? Do you get the engine up to full operating temp when you drive? Was the engine recently over revved? Raced? Did the car sit for an extended period recently? Are you seeing metal bits in the bottom of the oil pan or oil filter? Did you see a lot of sludge built up on the oil fill cap or inside the valve cover when you changed oil? Was the old oil black, thick, smelled burned or had an odor of gasoline? The point is, there are several factors in play here.

If you would be so kind, please follow up with your results.
 

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Registered
1994 S600 Coupe, 1995 S600 Coupe
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2,851 Posts
Really? A reasonable solution is to wait it out?
I am not trying to argue or anything but I have a internal noise associated with the engine and it sounds too risky to just drive and hope it goes away...
It sounds like lifter click. If you have good oil pressure, drive it a bit, and see if it clears. Watch your oil pressure during the drive. The oil change drain down might have freed a spec of dirt that temporarily stopped up a lifter oil feed. That sort of stuff happens on every make and model with hydraulic lifters.


Jon
 

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1996 S600
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13 Posts
Discussion Starter #9
Hi,


Thank you for your explanation it makes me feel little better. I thought it was the rod originally so anything else is good news. I see Jon has a lot of comments but I just wanted to check as it didn't seem "right" to me to wait it out when my engine is ticking, but of course I don't know nearly as much about w140 as some people here which is why I decided to post. So thanks for the input.

Also, can the valve issue cause engine to rev and bounce between 700 and 800rpm at idle?

Mileage is 145k and it was dealer serviced with records (CarFax) until 2018. Since then I dont have too many records unfortunately. The video I posted was with the car fully warmed up after driving for 45min or so. Weather here is super hot and that day was in high 70s and oil pressure was above 3 when driving. I did not race the car or over rev it, the most it reved is when I get on a highway but I dont think it passed 3000RPMs at any time.

When I changed the oil, old oil filter looked fine, no metal pieces and cams (through the oil cap looked pretty good). Old oil looked brown not black when changed, I did not smell it though.

I added some more oil last night and will start the car soon to see if anything changed over night and with more oil.

To Jon: I really hope you are right and it goes away. I will report back after more testing. Would it be a bad idea to add little more oil over the max line?
 

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Registered
1996 S600
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13 Posts
Discussion Starter #10
I just started it and ticking is gone after adding little oil (from between min and max level to the full line on a dipstick). Pressure is at 3, but I only let it idle for few minutes, will drive it around little later.

Also I noticed my driver side fan barely spinning. Will have to check that one.

 

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Registered
1994 S600 Coupe, 1995 S600 Coupe
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2,851 Posts
Hi,


Thank you for your explanation it makes me feel little better. I thought it was the rod originally so anything else is good news. I see Jon has a lot of comments but I just wanted to check as it didn't seem "right" to me to wait it out when my engine is ticking, but of course I don't know nearly as much about w140 as some people here which is why I decided to post. So thanks for the input.

Also, can the valve issue cause engine to rev and bounce between 700 and 800rpm at idle?

Mileage is 145k and it was dealer serviced with records (CarFax) until 2018. Since then I dont have too many records unfortunately. The video I posted was with the car fully warmed up after driving for 45min or so. Weather here is super hot and that day was in high 70s and oil pressure was above 3 when driving. I did not race the car or over rev it, the most it reved is when I get on a highway but I dont think it passed 3000RPMs at any time.

When I changed the oil, old oil filter looked fine, no metal pieces and cams (through the oil cap looked pretty good). Old oil looked brown not black when changed, I did not smell it though.

I added some more oil last night and will start the car soon to see if anything changed over night and with more oil.

To Jon: I really hope you are right and it goes away. I will report back after more testing. Would it be a bad idea to add little more oil over the max line?
Don't over fill on oil. Will cause issues.

3 on oil pressure is ok at idle. Should move close to the top mark when driving.

Hunting at idle can be caused by several things, but first get a cheap smoke tester and check for vacuum leaks. Also check the boots between the mass airflow sensors and the throttle bodies as they like to crack and split open with age, especially on the bottom. You might have to remove them to thoroughly check them. They are about $120 each.

Jon
 
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