First of all, I would park the car and not start until this gets fixed.

According to your earlier post, the chain only has about 70K on it, which means you might be able to get away with just a tensioner.

$1000 is the going price for tensioner, chain, rails, and oilers. The chain and tensioner are are maybe $200 in parts and maybe 2 hours labor at most. It is a simple job but you have to be careful to keep the chain tight and on the sprocket.

Remove spark plugs
Pull R valve cover
Remove tensioner
Grind link to break chain at top of sprocket
Connect new chain
Turn engine with ratchet on 27mm bolt on front of crank to bring #1 to TDC
Turn engine, feed new chain in, pull old chain out
Connect new chain with link supplied
Install tensioner
Turn engine another full turn and observe that cam timing did not change
Put valve cover back on, put plugs back in.

You might have to pull the fan and shroud to get a wrench on the crank bolt.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe