Misfire & Droaning noise at high revs

[derekpayne]

Hi

Just purchased a C180 (W203 model), and I knew I had to replace the front discs when I bought it, I also have replaced the rear shocks as they were worn.

I have noticed that at around 80mph or any other speed where the engine is at the same RPM range I have a moaning or droaning noise which seems to be coming from the N/S, also the engine appears to be holding back and has a slight misfire.

I have had a good look around, I found one of the exhaust mounting brackets was broken, I welded that up, I thought it may have started resonating at a certain rpm but the noise is still there, and only seems to appear when the I am accelerating at high revs whether it be at 50MPH or 80MPH.

I was going up a long hill yesterday at about 60mph and the noise was there until I throttled off, and the misfire was there as well until I throttled off.

I have checked the plugs and re-gapped them, I just wondered if anyone else had come accross this problem as I cant seem to put my finger on it.

I would be gratefull for any advise or thoughts on this one.

Cheers

Derek

 

[derekpayne]

Right,

Apparently on the W203, there is a known fault with the radiator failing and coolant getting into the auto gearbox and torque converter causing the said symptoms, so I am going to flush the gearbox and torque converter and refill to see if its any better, if so a new radiator is the order of the day.

I will let you know how I get on.

Cheers

Derek

 

[derekpayne]

One Question before I start this oil change:

Dexron 2 or 3 which one to use?

Cheers

 

[derekpayne]

Right,

I have changed the gearbox oil, drained the torque converter, cooler and the gearbox oil filter, refilled with 6.5ltrs of ATF.

Initial short road test of the vehicle suggested that it was a lot smoother than before.

Took it for a good road test today along some dual carrageways, and the droaning noise has virtually disapeared although I can still hear it faintly if I leave the radio off, but it disapears quickly as you pull through the revs, what appeared like a misfire has also gone and the car pulled smoothly well past 70 (I wont say what speed I got up to as I could incriminate myself) with no misfire at all.

So I would recommend to anyone who has a vehicle that has gone past 40,000 miles without a gearbox oil change, to get it done ASAP, it will make a difference to the smooth running of your car.

Cheers

 

[grober]

If you haven't repaired/replaced the oil cooler/radiator problem the problem will rapidly return sadly. You may have put the cart before the horse?

 

[derekpayne]

If it does return, but I don't think it will as I believe someone has previously fitted a secondary oil cooler on it, then I will do the job again but changing the radiator at the same time.

Thanks for your advice, watch this space for more news.

Cheers

Derek

 

[Dieselman]

The droning noise is usually the torque converter clutch and possibly the gear gear clutch packs vibrating as the friction material has lifted off the backing plate. If this has happened it will return.

 

[SilverSaloon]

is your name Derek Payne? mine too!!

cheers

Derek