Ivanrad

i just bought a mercedes 2001 c320 amazing car ! woot!. I purchased it from a responsible and honest software programmer that just wanted to commute from work to home. He has every receipt and service a and b performed on the date it was due. I bought the car for 6500$. and now i don't think I've heard it get progressively worse because its such a mild rattle. i am reading now that its the catalytic converter. theres not service codes that have popped up no malfunction codes or anything. Please help me. my local mechanic said it might be some protective plastic barrier .

Glyn M Ruck

I have no idea what your mechanic is talking about unless he means a loose exhaust heat shield.

Please try to explain this rattle & where it is coming from. Try & post a clip of the noise.

It could be anything from a Cat to a loose exhaust baffle to the purge valve ticking to a damaged suspension bush or rubber or if in the engine a small end bearing.

Take the car to Autozone to read codes just to make sure. It's free

Please give us more information & location.

Ivanrad

i just opened the hood and it seems to be originating in the belt area of the front. nothing looks loose. the car was involved in an accident and had the radiator replaced maybe that plays a part in it. Ill post a video soon. crossing my fingers .
autozone in california doesn't read codes for free anymore i just called .
Driving to the store really quick to see if the noise becomes different.

Glyn M Ruck

Ah - OK so it's belt area. So it could be a tensioner, alternator, A/C compressor, PS pump, timing chain etc. Most likely just a pulley.

Buy yourself a $50 OBDII scanner from Harbor Freight. Best cheapie on the market. You can't own one of these cars without one.



Remove the Poly V belt & see if the noise goes away. First check!

Obviously do not run the car for too long without the belt or it will overheat without the waterpump running.
Good luck!

Ivanrad

okay news update when i turn off the a/c the sound goes way down ..

Glyn M Ruck

You might have a compressor on the way out or it could just be the extra load on the system. Take the belt off & check everything it drives for noise. Also try & listen to another V6 Benz. The front end of these engines is not dead quiet.

The fact that the car was in an accident could mean something got damaged. Radiator might have clouted the A/C compressor. Also check the fan for damage. When you turn on the A/C the fan starts immediately.

Ivanrad

would this be reliable?
http://www.buy.com/retail/product.as...lerid=26076229

KalC240

better to get a reader that displays codes directly without need for laptop..

Ivanrad

but would it still give me the necessary code readings ?

KalC240

yes. most come with a manual and or PC software, explaining the codes , and also you can google any code for more information.

Ivanrad

okay sounds good thank you. how hard is diy maintenance like the belts etc

Ivanrad

also what about my smog , my cat passed the smog test, does that mean my cats are good

http://www.youtube.com/watch?v=2Ao6ZJr3GH0
updated video

Glyn M Ruck

If you passed smog your Cats are still effective.

I suggest that you buy a scanner that tells you what the code means without having to look it up & is known to behave with Benz. The little guy above is the cheapest that guaratees this which is why it's popular on this forum. One that you can keep in the glove box.

You can of course buy bigger units - here is what I use from Equus.

phister

Heres what I use. But as Glyn stated above, check everything along the belt. Sounds like it might just be the load from the ac compressor or something got messed up in the accident.

Ivanrad

okay sounds good . i might be just being paranoid the car in anyway isnt changing the ac hasnt gotten worse all the filters are in the right place and clean . its gotta be that belt , ac or something else . doesnt the smog guy listen for sounds ?

Ivanrad

okay its the ac compressor i kill the ac and after 10 secs the sound stops. when i turn it back on it vibrates like hitlers fridge

C230 Sport Coup

Does it make noise at ilde?
Belt tensioner and pulley is a common and easily fixed failure.

The plastic barrier your mechanic mentioned is probably the shield under the car.
They are a pain.

Ivanrad

http://www.youtube.com/watch?v=2Ao6ZJr3GH0
video of the issue thanks for your help

Ivanrad

no ideas?

FrankW

is the a/c working properly?

it might be one of the guide pulley bearing that wore out. can't really tell if it's a rattle or a grinding noise in the video.

Ivanrad

i think its more of a rattle . how much r pulleys

Ivanrad

the ac works fine. the air is weird, every time its on automatic it blows strong cold air, when its on manual i put the ac all the way up and it barely blows.

Glyn M Ruck

Those HVAC fan speed characteristics are normal.

You need to check that the gas pressure in the A/C system is not too high. But I suspect that the problem is the compressor or it's pulley. I strongly recommend that you have the compressor removed & checked. The pulley can shear off by design on these compressors & do incredible damage.

amo1858

sounds more like a tensioner going out. It usually makes more noise with the AC on because the AC is an extra load on the tensioner and it rattles. alot of times you can turn on the AC and watch the tensioner vibrate more, a dead give away.

Ivanrad

I had a mechanic carefully listen and diagnose my ac compressor sound issue turns out mine sounds excellent blows cold but needs the canal near the windshield , to be cleaned bunch of leaves and pine needles in there. easy fix.!
Thanks everyone for your help.