Ian Cameron wrote:

> I AM a statistician, and my guess is that we can find out why these
> head
> fail with a high degree of certainty.   .......   Once we've agreed on
> the
> important variables, I'll structure a survey form and owners can
> answer it
> and someone (not me) can collect and collate the data.  I'll do a
> regression, and presto! we'll (maybe) have a better idea as to what
> goes
> wrong.
> VARIABLES
> Coolant type, pH of water, time between coolant changes, average
> length of
> trip, average speed during average trip (including stops), range of
> ambient
> temperature during driving year.  More?  Fewer?
> Ian Cameron
> U of Victoria
> Victoria, B.C.

Excellent!  Now we can take a significant step toward knowing the cause
of head gasket failure and how to prevent or delay it.  Aside from Ian's
help, the two things we need are variables and the data.  I have
included a tentative list of variables I think are important below.
Please comment or submit a list of your own.

As far as the data goes, ideally everyone would fill out the Survey Form
once it is finalized, and send it back to the data collector rather than
the list.  Then the data can be provided to Ian for statistical
analysis, the results of which would be posted to the list.  The raw
data can be stored in the list files rather than the archive.  Hopefully
everyone will take the two minutes necessary to return the Survey Form
so the study really is meaningful.  Better to invest two minutes than
two grand on new heads if you can...

TENATIVE LIST OF VARIABLES

______   Model Year
______   Current Mileage
______   Mileage When Head Gaskets Replaced ("0" if never replaced")
______   Mileage When Leaks Appeared ("0" if no leaks)
______   Mileage When Gaskets "Failed" [Vehicle not drivable)("0" if
not  apply)
______   Coolant Type (Phosphate/No Phosphate/VW)
______   Water Type (Tap/Distilled/de-ionized)
______   Frequency of Coolant Change
______   Climate Where Vehicle Used (Cold/Cool /warm/hotNEED HELP HERE
______   Usage (Daily, Weekly, Monthly)
______   Driving Type (mostly town, mostly highway, equal mix)
______   Frequency of Short Trips of Ten Minutes or Less (Daily, Weekly,
Rarely
______   Warm Vehicle Up Before Driving?
______   Ever Experience Overheating Problems
______   Have You Augmented the Ground Wires at Engine/Head/Frame?
______   Garage Kept?

Others???  Fewer???

>