THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM

C19704 the original, not the superceeded part number).

NOS not used.

we all want one.

Found this on the web Jose.
https://www.etypeparts.com/c19704-origi ... -valve-nos
It says its for the Mk10 and the S Type and is original but this is not the original design that the S type had. I have attached a photo of the true original from my car. This one rusted out and I had to replace it with this new C19704 which is a different design. The part number is the same as the original.
If you have a C19704 of the original design NOS then you are a very lucky man.

yes Cass, that is the original C19704 Heater Valve (the Service Manual calls it Heater Tap and Heater Servo).

I have probably 6 of them, all used, all bad, but I found one recently in the Swedish car that looks promising.. just need to test it. When I removed it, fresh green coolant came out of it, but through the two ports, not the weep hole.

if we could get someone to remanufacture the rubber diaphragms inside, (there's two rubber pieces inside that deteriorate), we could get them remanufactured. It can't be impossible.

I sacrificed one to find out what's inside and you can see in the scan below it is a very simple design.

I too cut one open but I found the rubber diaphragms to be intact and the problem was that the inside had rusted out. The brown pile in the middle of the second photo is the rust that I removed from inside the lower vacuum bowl. If they had been made of Aluminium instead of steel they would have been fine or if the owners had used a decent anti freeze with a rust inhibitor from new.
I thought there was a guy in Australia who was refurbing these heater valves. I don't have his details but I am sure someone mentioned it in a previous post.

there's a firm in Australia that refurbishes Vacuum Actuators, (which these heater valves are), and I wrote to them asking if they could open and re-seal these valves, as well as remanufacturing them, whatever they need.

I think David wrote to them too.

how did you cut it open? Can it be resealed?

send me the good rubber diaphragms to get them reproduced.

I got lucky!! look what I found, a new old stock C19704 Heater Tap !!

[attachment=1]01-C19704-nos.JPG[/attachment

Found or bought and if so how much Jose?
Tell us where you found it and if there are more we might all buy one.

Cass, I sent you an email 2 weeks ago, since you didn't buy it, (and I waited, and waited), I bought it.

expensive? Yes. he knew what he had. I had to take a deep breath and pay.

Definitely new, has never seen coolant through its ports.

cass3958 wrote: ↑Sat Mar 10, 2018 11:05 am Found this on the web Jose. https://www.etypeparts.com/c19704-origi ... -valve-nos
It says its for the Mk10 and the S Type and is original but this is not the original design that the S type had. I have attached a photo of the true original from my car. This one rusted out and I had to replace it with this new C19704 which is a different design. The part number is the same as the original. If you have a C19704 of the original design NOS then you are a very lucky man.

Cass, the picture you posted above IS the one and only C19704 Heater Tap Valve of the S type, and only the S type, MK-X, and 420.

there is a somewhat similar Heater Tap only used in the Daimler Limo of the same period. So you have it reversed. The difference is the position of the vacuum feed and there is no mounting neck for the nut and bracket where it mounts in the S type.

I wonder who made them, there must be some documentation somewhere. It will surface one day. The upper half of the valve was made in aluminum, the bottom half in steel with a welded vacuum nipple with a threaded neck. Very smart little valve, and very few were made. Someone told me they were made by Packard. Not true. I've been looking at Packard GM, Ford, you name it Heater Valves since 2006 and I've yet to find anything close to it. Except one guy in Autozone who told me a 1965 Ford Galaxie heater valve would work and it did. Made in China, plastic.

I have 4 dead ones of those in the picture, a recent 5th one from a Swedish S type that has promise but I'm unable to test it right away, and the N.O.S. that I just bought. All the same as in the picture you posted, all 5 removed from S type.

C19704