earl3

^ yep

Carlo_Carrera

It is hit or miss.

wross996tt

Not trying to be difficult, but Everything you discuss here is hypotheses NOT FACT. The possibly mechanisms (physical, chemical, deterioration, etc.) are all hypotheses. There simply hasn't been anybody (including those with experience fixing the issue) actually running designed experiments to determine what mechanisms are at work and quite possibly it is an interaction effect (only to be discovered through factorial designs). BTW, you would call variation in the supplied adhesive a design flaw? Perhaps the design should be robust to the incoming materials, agreed, but to blame design for any variation in raw materials might be a little unrealistic.... Very few companies actually know how to do this type of work (robust design).

cdk4219

Please excuse yourself from trying to be difficult..... But, I really don't think that there will need to be any NASA style detective work to see that the fitting that was glued in has decided to depart from its moorings. One can also deduce that if some sort of adhesive was it's main and only form of anchoring ( which it is) that that has not done it's job. Utter nonsense.


It does make sense that the heater feed line pops out, as I would guess that there is a shut off somewhere downstream (when the heater is off) that doesn't allow recirculation and dead heads this fitting?


Of course we will have to do some very extensive testing on this hypothesis for some to understand it.

Essexmetal

Wross you are correct on the data and there is little to support which, when and why. You can bet Porsche has logged some FMEA time since the problems came to their attention. The problem lies in the fact they don't know which series run of parts don't have a possibility of failure. If your turbo, GT2 or GT3 pops a pipe on the street not to big of a deal, its the playing Russian Roulette on the track that has groups concerned. Besides taking yourself out there is a good chance that if there is a failure you can also take someone else out. As you pointed out there is no correlation to which set is going to fail so one needs to err on the side of caution. Removing the coolant and running Water Wetter reduces the slickness of the water on the track but it is still an unexpected change in grip for the guy behind you.
The problem escalated to a point at Mid Ohio they will not let cars run without pinning or welding.

CKD, the heater pipe is running at the same pressure as the rest of the system.
Also modern HVAC systems do not control the coolant flow for temp control but run the coolant full time through the heater core and the bleed the hot air off. Have not been into the 996 system but that is what we design for in other applications.
Rick

"02996ttx50

3m didn't intend upon the glue that made them post it notes and that worked out just fine. but glue is glue. surely there is some better way. i think it's the heat cycle thing too and wince when i think of mine at 111k its track days in the past and the propensity of these to fail as the years tack on... but this line sums it up from the poster that posited:

"forum derived subjectivity does not offset hardware derived reality".

i was bit sceptical before as to design flaws as causation, ( though miles from dock's planet ) and dubious..though i now think it's purely a matter of time with these and lookout. great! something catastrophic to look forward to!

jumper5836

I have to disagree, this is dumped out while moving leaving a long thin spray. Coolant doesn't evaporate that quick while water evaporates very quickly. Water in the case of not standing water just leaves damp pavement which there is not very much if at all, any grip lost and the water doesn't then transfer to the tire and stick on it. Coolant when sprayed leaves a sticky oily residue that is very slippery and when driving over it will transfer to the tire and stick to it. It could take several seconds of driving to scrub of the sticky coolant. There is a huge difference between the two.

wross996tt

Wow...you do realize it to Richard Feynman to figure out why Challenger failed....NOT NASA. You also realize that the tiles on the Space Shuttle are glued on (RTV)....seems that glue worked just fine in a rather extreme environment. I guess "utter nonsense"...LOL

Essexmetal

Jumper, my note was a bit edited. I agree with you about the two being very different. My point was missed. Many groups around the country will allow you to run Water Wetter in place of coolant as the fix for welding or pinning the pipes. My point was that it is not a fix just a less of an impact. Some do spray and some hose down the line very aggressively. We have had 3 owners with various levels of damage and 4 followers three with pretty much totaled cars. Every circumstance is different.

The science and results are well discussed, if someone is not forced to do the repair by the organizers then the rest is a balance between luck and intelligence.

Dock

And just what planet would that be?