This weekend is going to be ok for working on cars. I have installed my new water pump, but the radiator is not in yet (it is brand new). My block and heater core are full of oil-contaminated coolant, so I want to really douche the whole cooling system.

When I had my om617, I removed the thermostat and replaced the thermostat cover and hooked up a hose to flush the system. Then I ran the engine with Shout for about 20 minutes, then let it cool and flushed again.

Now I have this om603 - and am trying to figure out the best way to pre-wash as much as I can before installing the radiator (don't want to get it all dirty inside). If I attach the lower split radiator hose to the thermostat housing and the heater core, and connect the upper radiator hose to the block, but not the radiator, I am thinking that I can attach my garden hose to the upper radiator hose and flush fresh water through the entire system (including the heater) - am I imagining things? I'm not sure how to get the heater core clean without running the engine (it's not quite ready to start, should be ready by Sunday).

Ideas, recommendations ?

You can flush in multiple directions like cover lower hose fitting and flush from upper hose fitting to block drain, cover upper hose fitting and flush from lower lose fitting to block drain, isolate heater core and flush from monovalve to head and the other way...

Sixto
87 300D

I replaced my radiator over the summer on my W126 603. Buddy used a power flush, warmed it up, dumped water and re-power flushed.

So power flushing five times before he was satisfied the blobs of oil were all out.

Hmmmmm - 5 times. Now THAT's a good cleaning. I hooked up a hose today to the upper radiator hose (from the radiator side of the hose), and watched clean water come out of the bottom hose (good enough for now).