heater bypass valve question

killj0y · May 20, 2015

this might not exist but in case it doesn't has anyone fabbed up a stronger bypass? I ask because I've had it pop twice in just a few short years of ownership and it feels like a weak link in the cooling system. Before I go and start tinkering with ideas I was curious if anyone has found something not plastic. I currently have it bypassed which is fine but I do want a functioning heater when winter is here if only just for the missus.

RonD · May 20, 2015

I assume you have the 4 hose bypass/heat control valve.

Plastic shouldn't be an issue, Radiators are the same plastic.
If it is leaking out the actuator then get a Motorcraft replacement, even from wrecking yard, 3rd party replacements on these are often "leaky"

Older Fords w/AC often had the same 4 hose bypass/heat control, Pre-'75, made of metal but you would need to find NOS(new old stock) because current replacements would be plastic.
Some may also be cable operated so you would need to build/modify for vacuum actuated.

killj0y · May 21, 2015

RonD said:
I assume you have the 4 hose bypass/heat control valve.

Plastic shouldn't be an issue, Radiators are the same plastic.
If it is leaking out the actuator then get a Motorcraft replacement, even from wrecking yard, 3rd party replacements on these are often "leaky"

Older Fords w/AC often had the same 4 hose bypass/heat control, Pre-'75, made of metal but you would need to find NOS(new old stock) because current replacements would be plastic.
Some may also be cable operated so you would need to build/modify for vacuum actuated.

actually leaking isn't the issue it will be fine then the entire nipple up to the main portion just blows off and dumps all the fluid instantly. this last time I didn't have tools with me but I got lucky that I had a multitool in the glove box along with a mini mag I was able to bypass it using that and I always have extra coolant in the toolbox.

RonD · May 22, 2015

Only 16psi of pressure in the system, which is nothing to sneeze at, but still isn't all that much pressure for molded plastic to fail.

killj0y · May 23, 2015

RonD said:
Only 16psi of pressure in the system, which is nothing to sneeze at, but still isn't all that much pressure for molded plastic to fail.

unfortunately I didn't have a pressure gauge on it, but it did fail twice the first time I have no idea the age or condition of the valve. the second time it had been in there less than two years. that's about all I know at this point. the only times my cooling system has failed has been this valve. once during my drive home (about 20 min) the other driving on the beach.

RonD · May 23, 2015

Rad cap is the pressure release valve, rated 14-16psi, and if it was bad it would take less than 2 years to know it

Is the by-pass valve under stress from a hose, or hoses being too short?
Often times ends of hoses crack and people cut them off, which is fine, but if they get too short then it could put stress on a plastic part.

adsm08 · May 23, 2015

If you weren't in Texas, or a similarly warm area, I'd say just delete the bugger with some metal barbs. Since you are in the south you might notice the minute loss of AC efficiency.

killj0y · May 23, 2015

adsm08 said:
If you weren't in Texas, or a similarly warm area, I'd say just delete the bugger with some metal barbs. Since you are in the south you might notice the minute loss of AC efficiency.

well as of right now it's bypassed with a straight through coupler and the ac has suffered a bit but it's doable. still considering not replacing the bypass until I need too around November or december. I'm considering doing an electric fan conversion maybe this will finally convince the wife.

Dune Runner · May 26, 2015

The replacement control valves being sold are cheap chinese junk. I replaced mine a few months back and I just noticed it's leaking already. Bought a Motorcraft one and though it's made in Mexico it looks just as cheap. I will keep an eye on it and see if it holds up any better.

RonD · May 26, 2015

I think in the late '60's and '70s cars with A/C used similar 4 hose bypass/heat control valves, with all metal construction

These would most likely be cable operated but could be modified for vacuum control.

killj0y · Feb 8, 2016

I keep hearing about metal valves but I can't seem to find a metal 4way valve only 2 or 3 way. Bummer guess I'll try the motorcraft one and keep the barbs around the toolbox just in case.

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heater bypass valve question

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