I had to do this on an 87 190D, obviously it is not exactly the same.

I used a 3 foot section of 3/4"/19 mm ID heater hose. Ran the hose from the end of the heater coolant feed pipe over the top backside of the engine to the heater coolant return engine connection. The feed pipe in that configuration ran from the waterpump/thermostat housing at the passenger side front of the engine back towards the rear of the engine on that side. I disconnected the hose which connects the feed pipe to the vacuum control heater valve at the end of that pipe. If you know the hose clamp is in good condition you can reuse the one that is there, if not bring a good one with you. Attach the hose to the pipe and run it behind the engine over to the passenger side. Find the outlet from the heater and follow the hose from that to wherever it connects back to the block on the driver's side of the engine. Disconnect the hose from the heater from where it connects to the pipe or bib going into the block, get the hose situated so it's not rubbing or interfering with anything and you can close the hood, the you can cut off any excess and secure it in place with another good hose clamp. I ended up cutting about 6 inches of extra hose off the original 3 foot section to get everything to fit well. Bring whatever tools fit your hose clamps (benz factory clanps are usually 7 mm) and it will be easier if you have about a foot of extentions to reach down to where the end of the pipes and the hoses meet, otherwise you've got to reach your hands down inbetween stuff and that can always be a problem. Bring some premix coolant or water to top the system up as you'll lose some small amount of coolant when you disconnect things opening the system. A couple nylon tywraps to hold anything in position if needed and you should be good to go.