Knock in rear suspension - only when cold
 

87 SL 560 Very profound knocking when going over any kind of bump. Renewed exhaust hangers, no luck. Coming from rear driver's side, but only when temperature is below about 50 F. Could be oil in shock getting stiff from the cold? Mechanic says it looks like rear shocks are leaking. Going to replace shocks and rear subframe mounts. I think I read somewhere to try rocking the body left and right to test for sway bar linkage problems. That does not make any sound and suspension seems tight. Suggestions? Things to anticipate? Tips? Ever had similar problems?

Sure did.

Turned out to be a busted rear sway bar link on the driver's side.

warmer now, no knock
 

It has warmed up a little here in Phoenix in the last week and there is no knocking at all. Seems if it was the sway bar link that temperature would not be a factor. I am thinking shocks or subframe mounts. Oil in the shocks and rubber in the mounts would change with temperature.

Put on new shocks over the weekend. It is cold this morning. NO MORE KNOCKING. WOO HOO.