Cooling System - To Flush or Not to Flush?
 

After draining my coolant, I was planning on refilling it with plain water and letting it run at normal operating temp for a few minutes. After it cools, I am going to fully drain the system and refill with anti-freeze. It's an '85 325e, and from the looks of the coolant reservoir it looks like it needs a good flushing out.

Any thoughts about if this makes sense to do? What is recommended for cleaning out the system?

I have done exactly what you have described.

You could also run a coolant flush additive first (200miles or so) then, go straight water, then back to coolant.

What would you recommend for a coolant flush additive? I was under the impression that those additives could cause damage to some components or sensors.

I wont hurt the sensors.

I dont necessarily think you need to flush it. I depends on how bad it looks. But with a 1985 model a flush might remove some of the heavy deposits.

I used Prestone Superflush.

If everything is working fine and you are concerned then just leave it.

Use a flush, then use distilled water until it flows clear. Fill with coolant afterwards.

Well I ended up just filling it with tap water, running it at operating temp, then drained it again the next day and refilled with anti-freeze. One thing I'm dissapointed about is that I used a pre-mixed antifreeze and even though I drained the system at the engine block, it must still hold a significant amount of water because my anti-freeze is reading a bit on the weak end of the scale with a tester.
I was under the impression that if you had your heat controls set to high, and drained the radiator as well as the engine block, you get pretty much everything out of the system. Apparently this may not always be true.

Good point & very frustrating. How's things now? Interested in your progress.

Cooling System - To Flush or Not to Flush?
 

They flush out their garden hose each spring to make sure it is not plugged up.
.... cooling flush I didnt have cash 4 radiator upp lower hoses ps flush etc.
... How often should you get an induction service and evap system flush and