GT-350 Water Valve

[oldcanuck]

Yesterday.... out for a nice fall cruise. All was going well.... running well on fresh 93 pure......good oil press and water temp.

On the way home I notice all of a sudden the water temp gauge goes down to nothing, then pulling into my driveway I hear a little hissss.... by the time I get out and open the hood, full on hissing and a little steam from the water valve on the passenger side of the firewall..... small puddle of coolant about the size of a basketball....

I assume after 56 years the old valve has given up......  Do these things wear out, and when is the best place to get a good replacement.... NPD ?

Thanks in advance.

[Bob Gaines]

Yesterday.... out for a nice fall cruise. All was going well.... running well on fresh 93 pure......good oil press and water temp.

On the way home I notice all of a sudden the water temp gauge goes down to nothing, then pulling into my driveway I hear a little hissss.... by the time I get out and open the hood, full on hissing and a little steam from the water valve on the passenger side of the firewall..... small puddle of coolant about the size of a basketball....

I assume after 56 years the old valve has given up......  Do these things wear out, and when is the best place to get a good replacement.... NPD ?

Thanks in advance.

It depends on your expectations. NPD sells a replacement that will work but doesn't look exactly like original assemblyline .There is a O ring between the body and the bracket . That is the place where coolant typically comes from . If your lucky you may be able to easily replace that .  It is a hardware store item. Sometimes the screws holding on the bracket to the body or frozen. That can be a problem if wanting to replace the O ring. The inside valve can corrode to the point it ether does not pivot and close off flow or the little paddle stopper that stops the flow corrodes away. That typically renders the valve useless. Keep in mind when inspecting that the valve doesn't completely close off flow just the majority of it. The next possible problem is the vacuum pod . You should be able to apply vacuum to the nipple and see the valve inside move . Also when you apply vacuum and cap off the nipple to the valve it should hold its position . If it doesn't then the rubber diaphragm inside the vacuum pod is compromised . i don't know anyone rebuilding those vacuum pods so this renders the valve useless too. Sometimes you can find NOS units . If you find one for less the 250.00 it is a deal . Used units can be viable but they need to be inspected for all aspects that I mentioned . 

[oldcanuck]

Thank you Bob.....

I will remove later it this week and report back as to I can see/identify.

Due to living in the southeast, and the car being black..... I don't think I have ever turned the heat on.... could that be part of my problem, or partly to blame ?

Bob

[Bob Gaines]

Thank you Bob.....

I will remove later it this week and report back as to I can see/identify.

Due to living in the southeast, and the car being black..... I don't think I have ever turned the heat on.... could that be part of my problem, or partly to blame ?

Bob

I don't think so. It may effect the movement of the valve if corrosion was able to buildup because of non use so it wouldn't move freely.The leakage is most likely due to corrosion acting on the seal area . That effect comes with age. What concentration of antifreeze you have will plus or minus the time this happens.

[Royce Peterson]

Usually the bracket rusts out that holds the valve to the firewall. Replacing the O ring does not fix it. You can replace the bracket with a new one or patch it with metal, then re - plate it. New brackets are pretty scarce.

As mentioned the anti freeze is likely the cause of the bracket rusting out.

[oldcanuck]

Actually nothing rusted out that I can see....and actually the valve being crusty on the exterior, is extremely clean on the inside.... ?  I run a 50/50 mix....but I cant say whet the POs ran in FL and CA before me...... the piston inside moves freely, but cant really see the range of motion. How does the valve come apart so I can check the o-ring ?

[Royce Peterson]

Three screws hold the valve to the bracket. You have to remove the three screws to see the O ring and the corrosion on the bracket. The valve must first be removed from the car.

[oldcanuck]

Three screws hold the valve to the bracket. You have to remove the three screws to see the O ring and the corrosion on the bracket. The valve must first be removed from the car.

Done did that..... and the gasket was in tact as well.... thats how I could see inside and the plunger/piston bottom or top.

[Royce Peterson]

There's not supposed to be a gasket. Only an O - ring. Someone added a gasket perhaps.

[Bob Gaines]

I have seen some occasionally with a paper gasket too . I don't know why all with or all without but at least some came that way.

[oldcanuck]

Guys,

I think I found the smoking gun..... after a more detailed inspection... I can see where the o-ring groove is in the triangular base plate of the valve. Looks like it may have been replaced by a thin rubber gasket. After peeling the gasket off the removable plate.... I see a small amount of corrosion on the plate, and the rubber gasket appears to have some tiny age cracks...... I guess I can clean it all up, make a new gasket and give it a little coating of RTV for assembly.....

I hope this is it....I appreciate your assistance Royce and Bob.

[Bob Gaines]

 I would use a O ring in the groove. I think it is stronger and more durable.

[Royce Peterson]

I would use a O ring in the groove. I think it is stronger and more durable.

Unfortunately Bob is correct - the O ring on flat non - corroded metal is what works. The coolant becomes acidic after maybe 5 years and must be changed to keep this from happening in the future.

[oldcanuck]

Neither a new o-ring or rubber gasket worked.

I'll be on the hunt for a replacement, but since my a/c has been in boxes and not installed in a few years, I'll probably just take the valve out of the loop and install the hose direct to the heater.

Again, thanks to both Bob and Royce for the assistance.