Wankenstein

'95 EX coupe, M/T, B20.

Heater valve is leaking when shifted from cold to hot. Can just the rubber o-ring under the arm be replaced? The prior owner installed an aftermarket heater valve. It only leaks when the ball valve is shifted..when stationary it's doesn't seem to leak.

ezone

Get a new valve from Honda?

Wankenstein

Yes..going this route ($45 thru HondaPartsNow).
The current aftermarket one doesn't stop at full lock hot and cold like an OEM does. I can spin the arm/ball valve 360 degrees. The ball valve on it never fully closed for a/c use with the given cable length so at the time I purchased the car last February and was having cabin cooling issues it was related to the heater valve not fully closing.

I ended up removing the heater valve, loosening the screw and spinning the ball valve in incriments while running water through it and when it got to the point of the least amount of water flow (closed position/max cold AC) I correlated that position of the ball valve/arm with the maximum cable travel length for "max cold" climate control setting.

However, by adjusting it this way it probably never really produces "max heat" inside the cabin because the ball valve never achievs the full-open position when the climate control is set on max heat. I live in mid-west Florida where a/c need (Donald) trumps need for heat. Even so, it still gets heat to the cabin.

I noticed on my old '98 EX the OE/OEM heater valve arm is limited in travel: range between open and closed with or without cable attached, and it doesn't spin 360 degrees. To add to this I believe this limitation in range in travel (ball valve hole) may be related to complaints of 5th and 6th gens not cooling well..along with the undersized compressor. Just a theory and no proof though. Even with the new OE/OEM part I plan to test it first by running water though it and see if truly prevents flow in the full closed position. If not I will adjust it as I did the current one mentioned above.