Replacing Drain Valve o-ring.

[Saml01]

So I discovered my damn drain valve is leaky. Not terrible but it is dripping. I found a thread that explained how to service it, so the first thing I tried was tapping it with a hammer. It didnt help. It leaks in the off position, doesnt in the on. My guess is, if the o-ring isnt shot then its probably packed in with crud causing a poor seal.

Two questions.

1. Has anyone found a source or have a size for a replacement o-ring?

2. Has anyone just deleted the valve?

I am leaning toward option 2 just to eliminate a point of failure. I would either plug all the lines OR loop the one coming down from the rad cap into the radiator, and plug the one that bypasses the thermostat.They should have just put a plug on the damn rad like in a car.

 

[jfeagins]

I buy o-rings either from the True Value hardware store here in town, or go to Lowe's. I take the old one with me and am able to match it up 99.9% of the time. Otherwise, I pony up and order either at the local Stealership, or online @ Mrcycles.com.

Lately, I've noticed Sean Morley is the "go to" man for most all parts Gen I. You CAN NOT GO WRONG buying from Sean, big parts or small.

 

[Saml01]

Does anyone know exactly how the drain valve directs coolant in off and on positions?

http://s495.photobucket.com/albums/rr319/saml01/?action=view&current=CoolantVmax.jpg

According to the diagram, if we assume the valve is OFF, it would make it seem that hot coolant is bypassing the rad all the time. In the ON it allows the rad to drain passed the thermostat. If my assumption is correct, ditching the valve all together will actually increase the cooling efficiency because all hot fluid is passing through the rad. The only thing that needs to be considered is why do they have the bypass, my guess is to increase coolant flow when the engine is cold, but that means you have decreased efficiency when the engine is hot.

 

[one2dmax]

You can probably take apart the valve assembly and clean up the corrosion and put it back together with the old o-ring. I probably do have a new one on hand anyway. Most of the time they leak where the pipe comes out of the t-stat housing.

Sean

 

[Saml01]

HA. I knew it.

This is the drain ON vs OFF side by side. Its only singular purpose is to drain the radiator.
The line that comes down from the waterneck isnt even tied into the valve, its simply a bypass around the radiator. This makes me wonder why they did that. I would imagine the thermostat has a hole in it to let some coolant pass until its up to temp when it opens completely. So ditching the valve is almost a no brainer.

 

[Saml01]

Just did some major thinking and nevermind. I cant get rid of it. The thermostat probably doesnt have a hole in it like I thought. It uses the bypass to get hot water behind it, thats why its there. Once thats up to temp it opens up.
If its true thats a hella gay design, almost makes me want to crack open the water neck and drill some holes in the thermostat to get rid of this line.

Anyone have a thermostat laying around so I can confirm?

 

[MaxMidnight]

Coolant flows out from the bottom of the radiator, through the thermostat to the pump.

My understanding is that the valve is there to allow coolant to drain from the radiator when emptying the system.
If it wasn't there then the closed thermostat would prevent the coolant from exiting via the drain plug.

When filling the system it will give air a path to exit.
Having an air pocket under the thermostat would be a VERY bad idea!

 

[Saml01]

Pretty much thats it. However you can fill the system with it closed off because you have the bypass feeding the same point behind the thermo. In the future, if it ever leaks again I will pull out the thermo drill some small holes around its circumference and ditch the valve.