How the heck do you do this? I can find the drain =/

My reservoir is REALLY low. Would rather flush than just top off. Is it safe to flush the system with water, too, to remove rust and other deposits?

 

it goes something like this:
-remove the upper radiator hose
-remove the thermostat from the housing
-put the housing back together minus the thermostat
-drain the reservior
-remove the radiator drain plug, if there is none, remove the lower hose and drain coolant (drain it to a proper container to dispose of properly)
-remove the coolant plug on the block and drain the coolant out of there
-get a garden hose and shove it in to the thermostat housing where the upper coolant hose was connected, turn on the water and flush out whatever is in there for a few minutes.
-repeat for the radiator
-reconnect everything, put the thermostat, block plug and rad plug back in, then fill the system with fresh coolant
-start the car for a minute, turn it off, top off the coolant, repeat several times until the reservior is at it's proper level

It's a lot of work and I don't really recommend you do it at home since if you don't have a proper place to dispose of coolant you can kill a lot of animals/ contaminate the environment. coolant attracts cats/dogs/kids.

I would just say bring it to a shop to do since you won't have to deal with disposal, and they can do it a lot faster and just be done with it.

 

There is no radiator drain plug, which was what was bothering me.

If anyone else was wondering, the block plug is under the intake manifold, on the back side towards the transmission side of the block. Check out 14-25 of the service manual.

Why do you have to flush via the thermostat housing? If you have to remove the hoses anyway, can't you just flush the block and radiator separately, and not mess with the thermostat?

Disposal isn't a problem for me, as all the local shops who sell coolant in my area HAVE to offer public recycling services by law. I do this with all my fluids. I have 2 dogs and a cat, so I'm very picky about disposal.

 

mmm.. some cars do have them, some don't. I'm not too sure about our RA's though. I know my sister's old car had a drain plug on the lower passenger side of the rad

The reason why you have to mess with the thermostat is because it's closed when the engine is cold right? so you would be able to flush the rad separately as described, but you won't be able to flush the block since the thermostat is closed and won't let any water in through the upper hose.

thats cool that the shops over there have to offer public recycleing services , I wish we had that over here but we have to bring our used oils and stuff to a recycling depot. nothing too bad, but sometimes there's a big line of cars dropping off sofas and such and it sometimes takes a while to drop off the oil.

Edit: just looked at the service manual and it says there is a drain plug...
and the thermostat, I might just be thinking about how to do it on my sister's car.
sorry for adding confusion.

try looking at the lower corners of the radiator, you might have to remove the front splash gaurd to find it if it's on the bumper side of the radiator

 

just looked at some pictures of evo 8 radiators (i heard that they are the same as our ralliart) appears it's on the lower passenger side of the radiator on the motor-side of the radiator

http://www.boombopracing.com/ebay/pi...676-EVO8-1.jpg

http://www.agencypower.co.uk/images/apevoradiator1a.jpg

 

I'll have to take a better look this weekend when I jack the car up again. There's a lot of housing around the edges that might make it a pain to get to. If thats the case and I'll have to disconnect the hoses anyway, then that might be easier over all Either way, the process should be pretty simple besides that.

As a side note, are aluminum blocks really that problematic as far as rust deposits go? If it's not such a big concern, it might just not be worth the effort at 40k miles. Maybe I can just add more coolant and not worry about a flush yet? I guess the only way to be 'sure' is to flush it and see how much rust comes out. If there isn't any, then I wasted my time, but at least I know I did the right thing

 

never hurts to clean anything

 

Our radiator has a petcock instead of a drain plug, that might be where you're confused. If you're standing at the front of the car, the petcock is on the bottom of the radiator on the left side.

If you only have 40k miles, and your coolant is still clean and at the proper dilution, I wouldn't bother flushing it. I never did mine until I changed my water pump at 120k miles, and it was still pristine. If you do decide to flush it anyways, change your thermostat, since you're in there anyways and they're cheap.

Finally, aluminum doesn't rust.

 

^ that's right. it corrodes

 

but the corrosion forms a tight layer of corrosion which protects the aluminum from further oxidation. unlike iron which forms a loose layer of corrosion which lets even more oxygen in contact with iron below the corrosion, which is why iron/steel never stops rusting. mind as well flush out the block though because it might have rust particles which came off some of the steel components in the cooling system