When To Fill Collant Overflow Bottle ?

[Wacky Dee]

are you meant to add coolant/distilled water to the overflow bottle (up to the "max" line about half way accross the bottle) when the engine is completely cold or hot ?

My understanding is, when the engine is hot it will blow coolant out INTO the overflow bottle ... and adding cold/room temperature coolant to the overflow bottle while engine is hot does not seem like the brightest idea (ie. adding cold water to an already hot engine block). And when the engine is cold, it will suck all the coolant from the overflow into the radiator... So I am assuming if I open the overflow cap to fill it up whilst engine is cold, the radiator might suck in air together with the new water (unless the radiator is full).

So in short, when the f#@&* am I supposed to add coolant to the overflow bottle ? Hot or cold ? Before or after topping up radiator ?

Oh and if anyone knows where the coolant bleed valves are an a R34 GTT please do tell I couldn't find it on the plenum (does the NEO rocker cover have to come off to see it??)

Also, how the hell do you bleed the coolant that's stuck inside the engine ?? Radiator drain drains the coolant from the radiator ..but how do you drain the coolant from the engine AND the heater pipes ?

I used to think replacing coolant was a simple task ...ugh

[lachlanw]

add coolant to the over flow bottle any time you want it makes no difference .

undo the radiator drain and pull the rad cap off . leave it for a while . it will all drain out .

surely you can do a search and a topic will even show you pictures where the bleed piont are . one is at the front on the leff kinda near #1 injector . cant remember if you have to remove "neo" cover as mine is permenantly off . rear one is about where the other end of the intake manifold is . they stick out like dogs balls because they always have a shiney gold sticker with red "do not open when hot" on them .

[mad082]

add water when hot or cold. doesn't really matter. although hot would be better as it will suck any back in if it needs it. if it is cold then just top up the radiator first then the overflow bottle. it's isn't an issue putting cold water into a hot engine because the very small amount of water it draws in will be up to the same temp as the rest well before it has made it through the radiator, let alone into the engine.

s for draining the coolant, opening one of the bleed screws will release the vaccum that will hold some water in the engine. i'm guessing you will probably need to remove the NEO cover to get to it. once that is off there will be one at the front of the plenum. it's a 10mm bolt with a warning label on it as lachlanw said. i wasn't aware of their being a rear one, but i had a 33, so they may have added one for the 34. i think there is also a drain bolt on the side of the block, however you don't really need to bother with that.

to drain all the water out of the heater, before you drain the coolant, run the car with the heater turned on for a couple of seconds (make sure fan is also on) to allow the tap to open. and leave it on when you turn the car off. then when you fill the radiator back up run the car and leave the heater on when you bleed the system.

[Wacky Dee]

thanks guys all that info will come in handy tommorow when I flush the system and put the new thermostat on