Radiator overflow hose/nipple - what's it for?

[steinbru at vnet.ibm.com]

Ref:  Your note of Tue, 23 Jul 2002 20:34:21 -0400 (attached)

Dave, you've fallen prey to a weakness in the design.  The plastic gets
brittle and the location is prone to having force applied, either to get
the hose off or from getting in the way of other work.

That is the vent, at highest point in cooling system, where air is
removed from the system.  This prevents vapor lock in the cooling
system.  There has been mention of a "repair kit" --but it was lousy and
temporary.  Folks have tried all kinds of things, with varied success.

I might have an end cap with an intact nipple if you know some place
that can do that kind of rebuild --the old rads *look* imminently
rebuildable but I never found any place that would actually do it around
here.  The plastic end caps are just crimped on over a gasket --I'm sure
it takes some fixturing to do the work.

I may be coming through before long, how stuck are you?  --Gary

----------------------------- Note follows ------------------------------
Date: Tue, 23 Jul 2002 20:34:21 -0400
To: quattro at audifans.com
From: Dave C <conner at cfm.Ohio-State.edu>
Subject: Radiator overflow hose/nipple - what's it for?

On the type 44 radiator ... what is the purpose of the overflow hose
connected from the top of the radiator to the overflow tank?

My little plastic nipple broke off.  While I'm trying to think of a way to
repair it I have to wonder why can't I just plug it up?  I think the
overflow setup is similar on the 4kq as far as the tank and pressure cap.
But instead of the overflow hose the 4kq has only a vent with a screw in it
... used to vent air from the system.  I think my radiator is solid aside
from this broken nippleotherwise... I just wiggled a bit too much on this
little plastic thingy while flushing the coolant and messing with the hose,
etc.

If this overflow hose is actually important/useful could someone suggest a
way to repair it?  I've not heard of a kit.  I'm thinking it might work to
splice a short piece of 1 1/4 inch OD pipe into the radiator hose with a
nipple attached to it somehow, and run the hose to it, then screw a plug
into the hole where the nipple used to be.  I haven't figured out which
types of pipe are available in the right dimensions or how to attach the
nipple.  If it turns out the overflow hose is unnecessary I'll be happy to
save myself the trouble.

thanks,
Dave C.