Okay so now that summer is fast aproching up here I want to be able to shut my heater core off without having to splice the lines together. I did a little reasearch and it sounds like I can't just shut one side off like on a Chevy, I'm going to actually need to be able to bypass the heater core when I shut it off so that it won't over heat the car. I already know one thing, im not spending $140 for a new oem valve. I could go to a junk yard and pull one off that I have no clue about and may or may not work, or I could make my own. I would like to make my own but I'm not quite sure how. my idea was a two valve situation, one for the intake side of the heater core and the other for the bypass pipe. So that when I don't need the heater I could reach down and close the inlet and open the bypass pipe. Hopefully the price would be closer to twenty bucks instead of 140 for the new valve. Another option might be a three way ball valve on the inlet side and make one off position open the inlet hose to the bypass pipe and close the heater core inlet, and the other would close the bypass and open the heater core inlet, that would of course cost more around $50-$60.

What do you guys think?

Edited April 4, 201312 yr by mikaleda

 I bought a couple of these and they aren't exactly the correct pipe size for the old oem hoses, but pretty close.  Might be the easiest route.  http://www.ebay.com/itm/300723733776?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

This one might be a better fit. http://www.ebay.com/itm/77-78-79-Subaru-GL-DL-Brat-1600-1800-Water-Heater-Control-Valve-Cable-OP-NORS-/321079248524?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D163%26meid%3D6732691103664024605%26pid%3D100005%26prg%3D1088%26rk%3D1%26sd%3D300723733776%26

Cool thanks for sharing, the way that valve looks, maybe I'm wrong and one side can be shutoff without overheating the engine. Does anyone know more about these heaters?

The cheapest option is to use 3 standard 15mm (or 1/2 inch) plumbing slim-line isolator valves; here in the UK they can be bought for about £1.00 each. Make an 'H' out of standard copper pipe. With olives or straight connectors soldered on to the ends to make hose clamping 'bumps' and two 'T' solder joints with an isolator in the 'cross bar' and an isolator on each 'riser', connect the 'risers' to the heater core in-and-out and the 'decenders' to the engine in-and-out. 

 

Pipe - about 12" length : 50pence from junk yard

3 valves: £3

2 'T' connectors: £1.00

4 olives: 20p

 

£4.70 - now that is cheap... What's that in $... about $7.10

 

When the weather warms up open the cross-bar valve and close the other two.

okay so i've been doing a little searching and i think i know what i want to do. firstly i'm going to get some copper tubing to make an H, on the inlet side of the H i will hopefully have a three way ball valve for selecting weather the water runs through the heater core or the bypass. next i need a way of shutting off the outlet side of the heater core so that it doesn't form a "drip leg" that could catch sediment in the cooling system and inevitably clog my heater core. i am thinking about what kind of valve to use on that, i would like a cable operated one so that i could connect it to the old heater control cable (if they didn't rip it out with the old control valve).

if i was able to do that it would be as simple as turning the knob to cold air and reaching down and turning the three way ball valve and if its done right it should last longer than the car. looking up what it will cost now, finding a used 1/2 three way ball valve that is in good shape might be the only way to make this feasible, but i'm not positive that i cant find a new one for a decent price. 

Is this for a pre-EA82 (i.e. EA71/81)?

Edited April 5, 201312 yr by NorthWet

yes this is for my 80

i looked up the just the valves i would need and i can get both for $32, so with pipe and threaded connectors it would cost around $40 i think. that's not to bad but i'm going to see if i can make it just a little cheaper with the same quality parts, BTW the valves are bronze ball valves rated for 500 degrees and 400psi, i wanted overkill.

Edited April 5, 201312 yr by mikaleda

My heater control valve is leaking from the piston / lever.  

 

I'm curious how everyone elses DIY turned out.

 

If i put in a custom 3 way valve i still need to control the damper. How did others get around this?

 

thanks!

This may be a stupid answer but why couldn't you just unhook the hoses going into the firewall and join them with a short length of copper pipe? Come winter hook them back to the firewall.

Around here, the weather switches too much to not have a valve.

I would just put in another factory one since i have 5 or in your case put in one of these in the middle of the heater core inlet line. You could either do that in the engine bay or the cab then delete the factory one with 5/8" heater hose.

try looking for a heater valve for a 96 toyota corolla....very similar in design but easier found....I used one a few years back to bypass a $1300 mercedes benz control valve.