700tons

On a 2005 TSX, does anyone know how to drain ALL the coolant out of the system including the engine block. I can't seem to find any drain plugs on the block anywhere. Does anyone know anything about where these might be located ? Also, what's the best way to bleed air from the cooling system after a full drain/refill ? Or should I "flush" and refill instead ?

curls

I just did a drain/fill (as per the Helm's / Service manual) and it mentions nothing about the drain plug on the block itself. You can get about 5.5 litres (quarts) out using a simple drain/fill, and that's what they recommend.

Pretty easy overall:
1. Turn on car, set temp to "HI", turn off car.
2. With the car cool, remove radiator cap.
3. Place large container under the drain at the bottom of the rad. No need to remove the plastic undershield - there's a small access hole at the front that lets you see the WHITE drain plug (horizontally mounted, white "wings" on it. I needed pliers to break it loose as it was on really tight).
4. Loosen but do not remove drain plug. It will drain (in time) without removing the plug completely. If you remove it completely, prepare for a mess as it shoots out in 2+ directions!.
5. While that is draining, get a 10mm wrench and remove the two bolts holding the reservoir in place (L&R side near the top, hard to miss).
6. Remove cap from reservoir. Lift out reservoir and drain into acceptable container. Rinse it out if there's any gunk in the bottom, which there shouldn't be.
7. Reinstall reservoir. Don't put the cap back on yet.
8. Wait for the radiator to completely drain. As mentioned, this can take a while!
9. Once it's done draining, re-tighten the drain valve. Wipe area clean with rag.
10. Use pre-mix, or mix your own 50/50 antifreeze now.
11. Using a suitable and clean funnel, fill the reservoir to the MAX line. Put cap on snugly.
12. Using a suitable and clean funnel, slowly fill the radiator. It should take about 5 litres/quarts itself. Once it's to the bottom of the filler neck, replace cap LOOSELY. I would wrap a few rags aroudn the base of the filler neck as some will bubble out in the next few steps.
13. Start engine, turn heat back to comfortable setting (say 70*F / 20*C).
14. Wait for radiator fan to come on TWO times. Shut off car.
15. Using another rag and wearing eye protection, slowly and cautiously remove radiator cap. Watch for steam! I'd wear gloves, too.
16. Fill radiator to base of filler neck again, if required.
17. "burp" the lines by gently squeezing upper rad hose (as close to the engine block as you can). You might see air bubbles escape, and then the antifreeze level will go lower. Top-up (again) and repeat this step until you cannot get any more air out of the system.
18. Replace radiator cap tightly / properly.
19. Wipe up any spills/drips ASAP.
20. Drive for a few days and check level again when cold. Top-up if necessary.

Done!
(20 steps sounds complicated but its actually dead simple. This is straight from my memory of the service manual on Sunday. It's as accurate as you'll find without reading the manual yourself. Also note that it says to only use Honda Type 2 antifreeze/coolant but my research and consultation with a few mechanics said that the Prestone 50/50 extended life "all makes all models" stuff is perfectly fine even in Honda/Acura systems, so I went with that).

nigelboyne

just did this myself i found putting the rear wheels up on ramps i got just 6 liters out of the coolant system,total is 7.4liters. let it drain as long as possible, i to couldnt find a drain plug on the block. when filling up the system i found filling the resevoir up to the max first and then the rad while massaging upper rad hose didn require any more attention and no air in system.

700tons

Thank you both very much !