I am trying to find the proper way to flush and change the coolant in my 2005 Accord 4cyl. The procedure in my Haynes manual basically says to:
1.) Drain the radiator
2.) Remove the engine block drain plug (which they provide no picture of).
3.) Fill system with clean water and run engine until up to operating temperature.
4.) Turn engine off and allow to cool.
5.) Drain system as before, repeat above steps if necessary.
6.) Refill with proper mixture of proper antifreeze, blah blah blah.

Now my questions:
1.) The owner's manual says to replace at 120,000 miles or 10 years, then every 60,000 miles or 5 years. The Haynes manual just says every 60,000 miles or 5 years. My car has 104,000 miles on it. Is it ok to wait until 120,000 or should it be done sooner?

2.)I have seen posts here that say the block drain plug is above or beside the oil filter. Others say that this is a frost plug and don't mess with it or you're screwed. Is there a consensus on this? I don't know why Haynes couldn't have put a picture in the manual to clarify.

3.) Will the above procedure leave trapped water anywhere from the flush so that the Honda 50/50 premix will end up being diluted?

4.) I assume the overflow reservoir should be removed and cleaned out also?

Thanks!

 

The pdf of the 03-07 accord (you can buy from automanualsource.com) has a different procedure. It says to start the car and turn the heat on high. Shut off car and wait until the radiator is cool. Remove radiator cap, drain coolant out of radiator via plug on the bottom. Empty plastic overflow container. Then just refill the radiator. There is a good video on bleeding the air from the cooling system by ericthecarguy on YouTube. I should come up on a search.

That is all I did on my 05 TSX which is basically the same engine as your accord @ 120K miles. If you want to change the coolant early, it will not hurt anything.

 

Thanks for the quick reply! Are the manuals from automanualsource.com the actual Honda service manual by Helms? I was thinking about spending the $50+ for it but a $21.99 download sounds much better.

 

Yes, automanualsource manuals are OEM manuals.

Sometimes it is easy to remove lower radiator hose at engine or radiator to drain some additional old coolant. As long as you get most of it, you should be fine. I never have found the drain plug on my 94Ex, but I didn't look too hard.

good luck

 

I would not flush it, because the water remaining in the engine will dilute the coolant. I would also use Honda coolant, which is premixed, hence the first comment. I don't think the service manual says to drain the block, on the 4 cylinder, only the V6 because it has a block drain made for it. Only the radiator and the reserve tank, on the I4.

Remember to start the engine, and turn the heat up all the way. After you fill the radiator and reserve tank, install the radiator cap loosely, and run the engine till the fan comes on at least twice. Add coolant if needed, close the cap, run the engine again to check for leaks, and you're done.

 

I agree. I am going to follow the procedure in the Honda manual that TexasHonda gave me. Just curious why Haynes would publish a procedure that is contradictory to the factory recommendations?

 

Probably because the people who wrote the Haynes manual never read the Honda manual, and do it the same basic way for every make and model.