Rad plastic inlet failure mode

[Doug Johnson]

Does it seem as though there's a incompatibility between the hose and
plastic neck materials?  If so, would a very thin metal sleeve between the
neck and hose perhaps help?  Just a thought....

 ~ Doug


-----Original Message-----
From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com]On
Behalf Of Dan Cordon
Sent: Thursday, July 24, 2003 8:08 PM
To: Quattro List
Subject: RE: Rad plastic inlet failure mode


Having just had this experience on my 200 20V, I can agree entirely.
This is exactly the condition of my upper radiator neck when it finally
gave away. Luckily mine happened in the driveway, not on the highway!

--
Dan Cordon
Mechanical Engineer - Engine Research Facility
University of Idaho

<snip>

> Normally, the plastic is rigid and unyielding to attempts to
> deform it by pressing on it with fingers or by gripping it with pliers. As
> it nears the end of its useful life, the plastic becomes sort of punky,
> softer and more rubbery and easily deformed with pressure from the pliers.
> In the final stages of failure, one can grab the end of the inlet with
> one's fingers and twist off a piece almost the same as tearing the corner
> off of an asphalt roof shingle. The plastic has lost it's rigidity. All
> this is taking place under the covering of the rubber of the upper inlet
> radiator hose, which hides the deterioration from casual inspection. I
> suspect that the act of tightening the radiator hose clamp at this stage
> would accelerate the speed at which the system is moving toward
> catastrophic failure.
>
<snip>