Have a '93 220TE and the petrol engine is starting make a noise like a diesel, sometimes at start-up and when idling. Seems to be temperature-related, but not sure. Also getting a 'rattling' noise when accelerating at low speeds. Any suggestions welcomed. Thanks.

 

pinging?

 

No, it's more the sound of a diesel engine when idling - a 'clattering' noise, sometimes on start-up and then when the car is stationary. The noise under acceleration is difficult to describe: it's a sort of rattle, which disappears when the speed settles down: seems to occur partcularly when accelerating uphill.

 

it's a knocking noise then?

the noise in the diesel sounds like knocking especially if the fuel delivery is not the same on every cylinder. unburned fuel causes the knock.

in your case it is not a fuel problem but a mechanical problem. it must be the CONNECTING ROD.

during startup and the engine oil is cold, the viscosity is still low and therefore cannot circulate immediately. due to lack of pressure lubrication on the connecting rod bearing, the clearance got play, and have this noise. was this guess of mine make sense? when you shift to drive, the noise changes?

this is the only case that you might possible got in your car. it is not a valve tappet because you know this kind of sound.

make sure the oil pressure is 3bar at 2000rpm.

replace the connecting rod bearing before it start to damage the crankshaft journal. this way, you can save a lot of money and time.

 

Hi timguildford,

Have you ever found a solution to the problem mentioned above?

I have the same problem on my E220 sedan under acceleration. The sound seems to be coming from the passenger side, under the glove box somewhere.