2.5L running cold
 

The weather turned cool and my 300D only gets up to about 40c, first thing that comes to mind is the thermostat [COLOR=#A0A0A0]602-200-00-15-MBZ. Is there any special tools or special procedures I need to know about before I replace the 'stat?

No. Unbolt the housing, replace the thermostat paying attention to the clocking tab, plunger facing in toward the engine. Replace the thermostat seal as well. Bolt it back up, torque to spec.

It kinda sucks having that turbo in the way. It was a piece if cake on my OM601.

Well, I for one would recommend testing the new thermostat in a pot of water on the stove, so you have some confidence it will do the trick. I like to check for both opening temperature and also make sure that it fully opens at the specified temperature as well.

It's a good idea to test it. It would be more important to test a Duralast thermostat than an OE MB thermostat. I have gotten 2 bad thermostats from Autozone, but not one bad OEM thermostat.

These engines can be finicky to bleed. Remove one of the temp sensors by the upper hose fitting while filling so there's less to bleed. If you hear gurgling from the dash, there's air in the cooling system.

Sixto
83 300SD