martin lynch wrote:
> I have a 2001 Honda Civic and need to drain and fill my radiator. I
> have read some tutorials but have a few questions:
>
> 1) Some have advised draining the radiator, then filling with
> distilled water and running for a while, then draining the water and
> filling with coolant. However, if I put water in, won't that get
> circulated into the engine block? If so, when I refill the radiator
> with my pre-mixed 50/50 coolant (comes this way from Honda), then my
> coolant in the system will be super diluted as it mixes with the water
> I introduced into the engine block. Am I missing something here?

no, you're correct. i wouldn't call it "super diluted" but it's
definitely weaker than normal. you can top up with undiluted antifreeze
to get the right mix if this worries you.


>
> 2) If the car has a bleeder valve (not sure if it does, I'll have to
> check), how does it work? Do I simply open the valve while filling the
> radiator while the car is off? Or do I fill the radiator, close the
> radiator cap, then open the valve while the engine is running?

the latter.

>
> 3) If I do the bleeding method where I open the cap and run the
> engine, do I simply observe the fluid in the radiator while the engine
> is heating up, and pour coolant in as the level drops, WHILE THE
> ENGINE IS RUNNING? At what point do I need to worry that the coolant
> will get so hot that steam blows my head off? Or does this not happen
> since I'm running the engine with the cap off, preventing a pressure
> buildup?

fill as much as you can with the engine off. squeezing the bottom hose
helps a lot. then run and bleed air with the valve - if you have one.
if not, simply overfill the expansion bottle, run, then let cool
overnight. contraction on cooling will suck the fluid you need back
into the radiator, provided you have no air leaks.

other tips on effective drain include unscrewing the plug on the block
to let all that fluid out too, and keeping the cabin heater valve open
so that drains as much as possible also.