Cobra351

so according to alldata, the engine drain plugs are on both sides of the '03 V6.

my question is, is there a way i can drain all, or at least most, of the coolant simply by removing the lower and upper radiator hoses, after draining the radiator? i'm just trying to do a flush... any help would be greatly appreciated, thanks in advance!

94vtecmn

I've never seen a system that doesn't drain the entire motor by pulling the drain plug on the radiator. Are you sure those are not the "frost plugs" that you really never have reason to remove?

southie's civic

y would those come out to help a flush ?? wouldnt the coolant level in the head still be lower than the two holes those bolts go into

gwiffer

After draining the radiator, there was still a lot of coolant in the block after I removed the water pump on my V6. I let it spill out all over my garage floor, because I couldn't loosen the rear drain plug.

BLKFLSH

The drain plugs are lower than the radiator hoses, so they will let more coolant out. They aren't easy to get to, and I think the one on the front side has a temp sensor in it. There will still be some coolant left in the block, so I would not do a flush with plain water. Honda coolant is premixed 50/50, so any water left in the block will dilute that. If the coolant is not in terrible shape, I would just drain (as much as possible) and fill. When I did my coolant, I drained the radiator, and the rear block drain, and refilled, it took just under two gallons. You should also turn the heat on max, to let the coolant drain from the heater core. There is also a procedure for letting the air out of the system after it is filled with new coolant.

Cobra351

can you please point out where the rear drain plug is, and the procedure for letting air out? i would think the procedure is to pour coolant in with the heater at max, while engine is running

BLKFLSH

The rear drian plug is pretty much right in front of the passenger's seat, on the rear side of the engine block. I know you can see it with the passenger side wheel off. It has a small nipple on it, so that you can put a hose on the nipple, loosen the nut, and the coolant will flow through the hose into your container. If you don't use a hose, coolant will splash everywhere.
The procedure for getting the air out is in my 03 owner's manual, but it may not be in yours, depending on what year Accord you have. If I remember correctly, it says to fill the radiator, and the reserve tank, then put the radiator cap on one notch (not all the way down tight), then run the engine till the radiator fans come on at least twice, then top off the radiator, and you're done. Yes, the heat should be on full hot. Seems like alldata would have this procedure too.

Cobra351

thanks, will do. i didn't check alldata for that, because i wanted real world experience from someone who's done it. and we do have the same car, '03 v6 ex sedan(don't have the owners manual though)

BLKFLSH

Just in case you want it. You could register and sign in to Honda owner's link, and get all the owner's manual information there. The 03 owner's manual has a lot of information, such as spark plug change, coolant change, etc. In 06, when Honda started the maintenance minder system, most of the maintenance information was left out.