DIY coolant flush (2004)

[Willard]

I flushed the coolant this past weekend. Here are some cell phone photos of the work.

-Allow the auto to cool off overnight (make sure the climate control is set on hot when you shut the engine off)
-Remove the radiator cap
-Remove and drain the overflow reservoir
-Loosen the radiator drain plug (you don't have to fully remove). It is a white plastic wingbolt with conventional threads.
-Drain radiator
-Remove the block drain plug (19mm wrench)
-Drain the block and prepare for a mess
-Clean up the mess
-Wipe off the bolt/block and replace the block drain bolt
-Tighten the radiator drain plug
-Add coolant to the overflow reservoir (max fill line) and reinstall the overflow reservoir
-Add coolant (I purchased 2 gallons of the Honda Type 2 premix)
-Replace the radiator cap
-Rinse the splashed coolant off of the engine bay/block/exhaust pipe/etc.
-Warm up the engine and check for leaks
-Once the car cools off... check to ensure proper coolant levels

Notes:
-The block drain bolt was 'very' tight.
-The easiest access to said bolt is from the top (it is just behind the front header heat shield).
-Good luck and don't cross thread the bolt during reinstallation.

Radiator cap (wipe it clean before reinstallation):


Coolant overflow reservoir (a little tricky to remove):


Radiator drain plug:


I used a section of hose to help keep the mess to a minimum:


Hose that I used:


Location of the block drain (very 'fun' to access):


Tools needed:

[dustino8]

Thanks for the writeup Willard! Should be a sticky.

I just saw this for the first time tonight. I'm changing the gaskets on the water passage tomorrow so I was browsing. I've read the block drain can be tough, and I'm still a bit unclear on its exact location, but I have a service manual so I'm sure I'll figure it out once I get under there.

Thanks again.

[rocky]

Lets add most shops will run the engine with the expansion cap off to allow the coolant to burp the air out of the system-merely topping up the coolant level as this happens.

Also, keep pets away from any antifreeze-you only have to hear one dog in pain as a result to know how bad it is.

[Willard]

Originally Posted by dustino8

I've read the block drain can be tough, and I'm still a bit unclear on its exact location, but I have a service manual so I'm sure I'll figure it out once I get under there.

It is on the front side of the engine... and was 'tight'. The phone above was shot from underside looking up (the item at the lower portion of the photo is the header).

Have fun.

[dustino8]

Originally Posted by Willard

It is on the front side of the engine... and was 'tight'. The phone above was shot from underside looking up (the item at the lower portion of the photo is the header).

Have fun.

I had no problem finding the drain bolt once I got under the Pilot.

Just out of curiosity, by front you mean firewall side? I was a little confused by your description. Just another note, on my '03 the bolt is a 17mm, and there is a "nipple" (like a brake bleeder screw) threaded through the middle of the bolt that you can attach a drain hose to, then just loosen the nipple. It isn't necessary to remove the drain bolt in this instance.

I found it easiest to access the block drain from inside the passenger side tire then slide your socket and ratchet towards the driver side past the oil filter, if that makes any sense.

Overall, draining the coolant is a pretty straight-forward task. Removing the water passage, thats a whole other story...