93LexSc400

hi i have a 93 lexus sc400 and the heater control valve is leaking coolant it does not affect my heat or a.c but i would always have to refill up the coolant into the reservoir and coolant tank i have heard some people replace the solenoid and the leakin was gone or would i have to just replace the whole aasebly anyone help or thoughts thanks

Carfreak70

iTrader: (16)

I would just get a whole used one...

stockhatch

iTrader: (12)

I ditched mine and installed a pex 90° fitting instead. Works great, gets rid of the bulky valve, and circulates coolant that in theory cools the back cylinder.

93LexSc400

if i just join the tubes would i affect my a.c

stockhatch

iTrader: (12)

It shouldn't. The blend door in the hvac air manifold closes off heater core flow when the ac is on, so you should be fine.

bugjug

Get a shutoff valve for the summer, it will make a difference.

97sc300t

iTrader: (1)

mine leaked and I ahd to bite the bullet and buy one brand new
sux trust me-I looked for a while for a used one no luck.

LeeSC300

iTrader: (1)

Could you elaborate a little bit more? I'm looking at deleting HCV along with my entire A/C set up..

stockhatch

iTrader: (12)

It's nothing really complex. I just stuck a pex 90° 3/4" fitting in there in place of the valve assembly. You don't have to mod the hoses or anything. Just clamp the fitting in and go.

LeeSC300

iTrader: (1)

Is there any detriment to keeping it an open loop system then?

stockhatch

iTrader: (12)

Personally, I dont think so. I can still get cold air if I want, so I dont see the harm in letting coolant circulate. I think its probably better than letting the coolant stagnate in the lines and heater core, but I dont have any kind of data to prove or disprove the theory.

LeeSC300

iTrader: (1)

Replace then bleed air? Sorry. I'm new to working on cars but my mind is pretty mechanical so I'm trying my best. Lol

stockhatch

iTrader: (12)

Coolant loss was minimal for me. I stuck the fitting in, and had enough in the rad overflow for it to bleed itself after a couple heat cycles. Just add a splash of coolant or distilled water to the overflow if you lose more than a dribble of coolant. It will pull what it needs from the overflow.

pain

so I can take the valve off and just connect the hoses together ? Will I still have a.c. and is there more to it or just that

KahnBB6

iTrader: (5)

You can, yes with a male-to-male coolant hose adapter and and two screw clamps.

You will still have A/C yes. You just won't have any heater function when the HVAC controller attempts to bring in more or less heat via the VSV and vacuum controlled actuator that connects to the actual plastic valve.

It's still better to get an OEM replacement if available or to replace the OEM design with an (apparently now discontinued) Four Seasons/Everco #74636 valve which requires just a little Dremel shaving on one side and the little arm swapped from your original valve to fit in just like factory... but with that aftermarket valve gone from circulation now there are other DIY alternatives to replacing the heater control valve and getting the HVAC to control it. There is a big thread on that somewhere here.

But yes for right now you can just get an appropriate size coolant hose coupler and two screw clamps to bypass a bad HCV valve entirely for the time being.