C320 Make

Hello From Finland And I apologize for bad language. I have a problem which I do not get assistance from Finland. Studied car brand business performance poor. The car is a C320 V6 Auto (bensin) -01 year. Engine or gearbox is plop plop plop plop sound when the engine is warm and the gear connected to a D or R. Free set N does not produce sound. A cold engine produces no sound but the heat must be at least 40 degrees

The sound comes from 5 seconds to delay when the gear is set to D or R, and the engine is warm. So when in gear consists of a burden on the sound will play. The water pump is a new micro V clamp is a new driver for a new roller, new crankshaft damper.

The sound is not sharp metallic sound, the sound is a soft plop plop plop a flat, or NOP NOP NOP, difficult to describe. Is it the fault on the engine or gearbox? None of the other symptoms do not exist, otherwise the car is perfect and will change gears correctly.


Can anybody help me, I am grateful

C320 Make

I tried second Automatick C320 (gasoline) and it was the same voice as my car. But this car plop plop / NOP NOP sound is much much more quiet voice. Does this sound "normal" for this car model?

What's that sound is, I think this sound is, for many automatick C320 model, but my car is the same voice is much more noisy? What does this sound comes from and why my car sound a lot stronger than the second which I have tried

mleskovar

Sounds like the purge valve. Common, there is a TB to reduce the noise.

C320 Make

Thank you. But is it purge valve ticking sound sharp difference? This is not the same? Or? Purge valve ticking machine room from the front right side of the small "jar" Did I understand correctly?

This sound plop plop plop plop, and always in gear D or R sound never set N. Is it the same sound your car in gear? When the switch turns off (N) sound disappears.

This nop nop nop noise level at all times in gear D or R, but never sound gear set N

sound stops as soon as the switch is N (free)

Glyn M Ruck

The purge valve should click all the time - mount it on rubber or replace it to quieten.

It sounds as though you only have this noise when the engine is loaded in Drive or Reverse.

A cracked flex disc between the engine & the transmission (where the starter ring gear mounts) can cause this but the noise would be at the back of the engine & come from the bell housing. I'm not convinced that this is your problem.

Can you take a recording of the noise and attach it so that we can listen. We would all like to help & a recording will help with the language barrier.

47 is the flex disc with an automatic car. It attaches to the Torque Converter.

C320 Make

Thank you very much for your ansver, so friendly !

I speak on the phone and I tell specialist my problem...
Automatick transmission specialista say me on the phone that it is not gearbox, because it work very vell and that sound is not gearbox. i dont kow.

He get me one tip...timing chain tension tightener?

I dont know but the sound comes when the engine temperature is at least 30-40 degrees and the D or R gear with the brake in place. Now begins the steady tone for 5 seconds delay when connected to a gear (D or R) plop plop plop sound .... no metallic sound

When I move the selector to N position, the sound off.

Could this be a timing chain tension? Timing chain tensioner. Need to change the tensioner (TIGHTENER)? Or what?

Glyn M Ruck

It could be the timing chain tensioner or the Poly V belt tensioner or another pulley. The change in idle speed under load in R & D might make them more inclined to make a noise. I don't think it is the transmission.

Timing chain slap due to damaged tensioners is unusual but not impossible on the V6. More common on 4 cylinder engines.

Noisy belt tensioners, pulleys & AC compressor/alternator are more common on the V6 than timing chain issues.

C320 Make

Yes, it is a complex matter.

Feeling the engine without the belt. Without the belt Nop NOP / plop plop sound gear drops D / R setting about 40-50% of silence

What does that tell

rabney72

Take a sound clip and post it here if you can. There are way too may noise issues with these cars to narrow it down that easy.

Glyn M Ruck

Then I'm worried that the crankshaft damper pulley might be separating. It is a two piece pulley with rubber in between. There was a recall on these on some E320 vehicles. Used to break & fly around the engine compartment. Check the crankshaft pulley.

Post a sound clip.

C320 Make

I have a new crankshaft damper but knok knok is not stop

C320 Make

Hello. I believe that this is some sort of generally occur in "fault".

Can you listen to your own car in gear (D or R) include a voice engine front or near the front wheel replaced by careful listening. The voice is steady stroke Clank / NOP NOP NOP / plop plop plop. Sound stops when you switch (N) It must be a typical fault. Since my test drive the car to give the same sound but about 10 times quieter than my car. Does your car if you listen very carefully. Test for 2 people. Another person setting gear D and the other person will go and listen carefully. Making the test require a warm engine. Thanks a lot

i_am_amused

I would never have been able to write this *at all* in Finnish or Swedish, so props to you, even though it's a bit off

C320 Make

Thanks. It is not easy Have you understood what I have been told and written. Difficult to write precisely because my native language is not "English". The world is big place I know

I hope that I get the answer and everyone can understand my question. I believe and hope that I get the answer to the large family around the world of mercedes

i_am_amused

My understanding is that you are hearing a noise at the front of the car, that is only heard in D or R, but goes away in N (what about P?) You also hear it on a second car, but much quieter.

It sure seems transmission related, and hearing it on two cars is probably a good thing.

C320 Make

(P) and (N) there is no sound. Question: is this sound anyone else's car?

My car, this is a very powerful voice, it belongs to at least 7 meters away. Another car that I tested, and sounds very quiet when you put ear close to the front tire and listen to (D or R) is almost a quiet voice.

Is it my faulty car and test the car just a bit faulty? Or? I want to know how the other cars. Question

amdeutsch

Threads merged. Same problem. Same OP.

C320 Make

Finally someone the same problem

Do you have exactly the same problem?

Switchboard (D and R) sounds (N and P) is not

Is this you sound hard? Is the C320 the car and how much driving? I have 160 000 km. what makes the sound?

C320 Make

The car has been mercedes workshop last week. But I think that something has been hidden.

Mechanic inspect the car, he eyes closed? I do not know ? I think, is it possible these symptoms .. the fault is a rear engine mount? (Transmission side) When changing switches D or R as 5 seconds after the connection starts to sound continuous pnop pnop pnop pnop.

No sound will be if the engine cold. This is strange.

Glyn M Ruck

Transferring these across as well to keep in one thread:

See number 10 for left & right mountings & number 40 for rear engine/transmission mount.


Here is the method for replacing the mountings on the newer M272 engine. Very similar to the M112. The M272 is a quadcam version of the M112. Mounting part numbers are different but method for replacement is similar.

https://mbworld.org/forums/attachmen...gine-mount.pdf

https://mbworld.org/forums/attachmen...gine-mount.pdf

C320 Make

If the fault is that rear engine mount, so why pnop pnop voice should not be a cold engine?

Voting begins only when the D or R gear and the engine is a minimum of about 40 degrees.

Brings warm and faulty engine mount rubber does not stretch when warm?

Defective cold rubber more flexible? but here's the question: Is there a chance to warm up this rubber? and why there is no sound when the engine is cold?

C320 Make

The problem must be automatic transmission flexplate. I have found internet audio sample (camaro)

I have the same sound but the camaro sample sound a little more metal.

I just wonder why my car is no sound (N) or (P) anyway The sound comes from a wide area

It is impossible to locate I believe that the problem is that!

Is that part of the expensive? Is it a big job? How much about work and part of the price?

Glyn M Ruck

The Left & Right front engine mounts are silicone fluid filled (built in dampers) & as they warm up the fluid gets thinner & they become more noisy if they are damaged.

If it is the flex plate it will only really make a noise when it is under load in Drive & in Reverse or when you start the car by cranking the starter motor. The ring gear is mounted on the flex disc. Automatic cars do not have a flywheel. Only the Torque Converter & Flex Disc. The starter motor usually makes a noise so you can't hear the crack in the flex disc.

To change a flex disc requires you to remove the Transmission to gain access. Quite expensive for labour. Listen with a stethescope or a screwdriver against your ear & the bell housing.

A good workshop can look at the flex disc with a boroscope to see if it is cracked without removing the transmission.

Good luck!

C320 Make

I asked the expert importer. Fault can not be a flex disc. I do not understand.

What else could be wrong?

This is wery stranger

Glyn M Ruck

Have you checked the engine mounts? Has the "expert" importer heard the noise?

Please try & post a recording of the noise.