Mechanics

MERCEDES HELP PLEASE

1982 Mercedes Benz 300sd • 5 cylinder 2WD Automatic • 201,200 miles

I have a 82 300sd idles rough and white smoke black smoke when accelerating valves have been adjusted
Avatar
Sam30
February 20, 2011.



Check the compressions and report the readings here,

mark (mhpautos)

Mhpautos
Feb 20, 2011.
From front to back 1-310 2-300 3-0 4-300 5-315

Tiny
Sam30
Feb 20, 2011.
I would be looking at a fuel delivery problem, have you had the injectors tested?

Mark (mhpautos)

Mhpautos
Feb 20, 2011.
No but the number 3 cylinder has no compression

Tiny
Sam30
Feb 20, 2011.
OHH sorry I did miss read that, early morning here and I am still having a heart starter coffee. Well no comp is a problem, you will have to get a leak down test done, this is a air fitting fitted into the glow or injecter port and at TDC on that cyl low pressure air is added, you will hear it leaking out the exhaust or inlet if a valve or in the Rocker cover if a piston problem, I would also just re check the valve clearances on that cylinder as well.

Mark (mhpautos)

Mhpautos
Feb 21, 2011.
I have checked th em again and again they were reall tight whene I got car couple weaks ago could it be a burnt vvavle

Tiny
Sam30
Feb 21, 2011.
More that likely it will be a burnt valve, the leak down test will prove this, regardless with no compression the head will have to come off to investigate anyway.

Mark (mhpautos)

Mhpautos
Feb 21, 2011.
Ok how can you tell a burnt valve by looking at it

Tiny
Sam30
Feb 21, 2011.
Best way to check with the head off, is that it will be visible burnt with a section burnt away, if it looks ok, with both valves fully closed invert the head and pour a little kerro around the valve, if it drains away, leaking valve, but with 0 comp, I feel that you will see a bad valve quite easily.

Mark (mhpautos)

Mhpautos
Feb 21, 2011.
Removed head the piston has a hole bout the size of a dime in it thanks for your help I wont be fixing this one just part it out

Tiny
Sam30
Feb 27, 2011.