Any time I've ever done a coolant flush, I put tap water back in, and although I've never had any cooling system problems, I think I'm going to switch to distilled water from now on (after reading here). But when I do a flush, I normally pull the radiator drain plug and collect the coolant, then I either do one of two methods:
1. Fill the radiator up with the hose pipe, run it, and drain it while collecting to dispose of, doing this a couple times. It's hard to have enough jugs to collect it more than a couple times, and after that it's really diluted anway, so I just let it drain to the driveway. What do you think?
2. When I did my Nissan Frontier recently, I was able to pull the drains in the block to get quite a bit more out. Since I think by then, I had drained at least 2/3 of the coolant capacity (other than what's in the heater core?), I closed the block plugs, left the radiator plug open, and just put the hose pipe in the radiator neck (letting it fill), started engine and ran until what came out of the radiator plug was perfectly clear (which didn't take long as I think by then it was near clear to begin with), letting that fall to the driveway.
Now, if I do method 2, and drain the block drains again before filling with AF and distilled water, is there still too much tap water left in the system? If so, what I can do, which is what I'll have to do for method 1, is to do one or two final fills/runs/drains with only distilled water before adding the AF. This would prevent having to use the distilled water for several drain and fills. And I just like using the hose pipe and letting it run while draining to completely get rid of all the old coolant. Otherwise, if just draining and filling, you'll always have some old AF left in there. Should I not worry about that?
Unfortnately I think the block drains on the '87 300ZX are harder to get to (turbo), so I'll probably do method 1.
1. Fill the radiator up with the hose pipe, run it, and drain it while collecting to dispose of, doing this a couple times. It's hard to have enough jugs to collect it more than a couple times, and after that it's really diluted anway, so I just let it drain to the driveway. What do you think?
2. When I did my Nissan Frontier recently, I was able to pull the drains in the block to get quite a bit more out. Since I think by then, I had drained at least 2/3 of the coolant capacity (other than what's in the heater core?), I closed the block plugs, left the radiator plug open, and just put the hose pipe in the radiator neck (letting it fill), started engine and ran until what came out of the radiator plug was perfectly clear (which didn't take long as I think by then it was near clear to begin with), letting that fall to the driveway.
Now, if I do method 2, and drain the block drains again before filling with AF and distilled water, is there still too much tap water left in the system? If so, what I can do, which is what I'll have to do for method 1, is to do one or two final fills/runs/drains with only distilled water before adding the AF. This would prevent having to use the distilled water for several drain and fills. And I just like using the hose pipe and letting it run while draining to completely get rid of all the old coolant. Otherwise, if just draining and filling, you'll always have some old AF left in there. Should I not worry about that?
Unfortnately I think the block drains on the '87 300ZX are harder to get to (turbo), so I'll probably do method 1.