irokdastar

Hey everyone . So I was in my car today with the widows up and music and I noticed when I am in drive and I start giving gas to move it sounds a bit like a tractor or diesel . But when I put it park and Rev it sounds ds fine . Is this normal ? No warning lights or check engine light .

SHARP2177

I remember reading about this in another thread on this site. I am not able to find it today, but the owner found out that his catalytic converter was getting clogged up. Its an easy check at a muffler shop. They drill a hole somewhere close to the beginning of the exhaust, engine side, stick a meter in the drilled hole, and monitor the backpressur of your system. A matter of seconds will show stopped up or not.

irokdastar

does this mean i need new cats ? and how come this only happen when i am in drive not park

C280 Sport

Is there any rattle? When you say it sounds like a tractor like rattle and clanking noise?

irokdastar

It sound like a diesel . If you Rev a diesel it sounds like tick tick tick . It's not valve slapping . It's just sound like a diesel running . I do have a clunking when going over bumps but that's a suspension issue . Like I said when I put it in Park and Rev it sounds fine .

Fatz

A diesel engine does not have spark plugs. The fuel is detonated by the heat caused by compressing the air. If it sounds like a diesel, it could be due to pre-denotation.

I'm no expert but pre-detonation could be due to low octane fuel, bad fuel, a firing issue, or even a clogged cat, as suggested by sharp2177.

irokdastar

can it be an exhaust leak causing the sound ? i dont think its clogged cats because it only does it when the car is driving not stationary.

Fatz

I guess it could be an exhaust leak. I've had an exhaust leak before and the sound did not resemble a diesel. It was more of a low frequency hiss and it could be heard when stationary and revving the engine.

Is the acceleration or performance less than before you noticed the sound?

If performance seems the same with no hesitation or bogging down, then I think it could be an exhaust related issue. If there is a leak and it is on the underside of the tubing you might see a small water pool under the car; other than that just aft of the oil pan area when you run your A/C. If the exhaust is stock however, I think it is unlikely that there is an exhaust leak.

Do not discount a defective cat and or downstream blockage due to dislodged pieces of the cat core. A reputable muffler shop of indy should be able to eliminate the exhaust fairly quickly, as pointed out by someone else.

irokdastar

It drives fine . i did not notice anything out of the ordinary . i am going to take it to my mechanic on Tuesday and see what he says . Thanks for the help.

SHARP2177

Hi,

I would make all easy checks first. You are on the right track by checking possibilities online before throwing a lot of cash at the problem first. So, I would check the exhaust pressure as an easy check, but check fuel grade and other easy checks mentioned in this thread also. My CLK500 has run great so far with 135000 miles. But I keep up with these threads to keep informed and possibly save time and money later.

sukalewis

ra
This is also happening to me

Fatz

What work was done my the mechanic?

BenzAMG99

were you during the rain