I have a 2005 RV class C sitting on a 2005 Chevy Express 3500 with the 6.0 V8. I started to flush the radiator and the coolant system and did not get much rust out of the fluid. Just wondering if I need to use a chemical flush. I did not drain the block using the drain plugs on the side of the block. Not easy to get to. So I drained everything and then filled it up with water and got it hot (190 degrees). Used a burping funnel on the radiator cap and waited until all the bubbles stopped appearing. Now will see what the fluid/water looks like when I drain it again. The procedure to drain and fill is such a pain. No drain plug on the radiator. Have to remove the lower hose and upper hose so it can drain and then fill.
A chemical flush might be too much. Any thoughts
The heater works and I have never had it overheat.
I have driven it pulling a jeep all over the USA and pulling hills has never overheated but it does get up above 210 f. I just turn on the heater and open the windows until it cools back down.
I need to add 50/50 mix but I know there is still going to be some water in the engine block. Is that going to hurt anything? Should I use full strength and just add half as much coolant with the water? We have really clean water here in CA. East Bay Mud.

 

If the water looks clear after a couple fu\lushes I would call it good. When was last fluid change?

 

Not sure since the rig has been sitting for a few years. I occasionally take it out for a few miles run. I am thinking the rust maybe just from sitting for awhile.

 

I have ordered a new radiator cap as they do go bad after many years. Anyone know how much fluid is let in the engine block? I wonder if I just ran the engine for a few seconds to make sure as much water as possible can get flushed out using the water pump. Any comments?