Date registered: Apr 2008
Mentioned: 1 Post(s)
Quoted: 2 Post(s)
The 250C has an in-line single overhead cam six with a bulbous single valve cover. The spark plugs are on the driver's side. The 280C is a dual overhead cam in-line six with a relatively flat "dual" one piece valve cover. The spark plugs are located on top between the cams. Can you isolate whether it is a top end or bottom end noise? The lower end noise is very uncommon, and as said above, they're pretty bulletproof. More common are top end problems caused by oil starvation. Bottom end noise will be at engine RPM and come and go in intensity with slight throttle movement. The noises will be more like dull, relatively low pitched thuds, maybe accompanied by slight vibration. Your oil pressure also may by lower than the high normal of these MB's. The top end noise is half engine RPM (slower), more typical, and be a higher pitched tapping or knocking. This may or may not be continuous, and not generally affected too much by throttle movement. Take off the oil filler cap and check for fresh oil wetness, and note if there is an abundance of sludge. If so, the top end oil feed holes may be plugged or restricted. This is common when oil is not changed regularly and/or repeated overheating. Also, the newer oils are much better than the oils of this vehicle's era, so much of this type damage may occur over many years of less than adequate preventive maintenance. Let us know what you find.
They're not "rare", but there are not too many "really nice" ones around. What is the condition of the rest of the vehicle? How well do YOU like it? I've had my 280C for 23 years, and I don't care what "stated book or average" value is. I love it, and will probably hand it down to one of my sons like I did my 250S. I did put the stipulation on the 280S that it goes to his son when he is done with it, as I got from my mom when my dad passed away in 1990, and he bought it new. The April 2009 Old Cars Price Guide shows the '70 250C shows a price range from junk ($700) to pristine ($17000), and a comparable several year newer 280C up to $18000. Hope this helps.
Last edited by mbbuff; 04-04-2009 at 11:30 AM.