Radiator Cap

[Shannen Durphey]

>
>
> What difference does the rate of flow have to do with heat transfer ??
> Like I said, seems to me that it's totally irrelevant as long as the
> liquid stays in contact with the metal -- in fact, seems t'me that the
> faster the better, since that keeps the delta-T at it's highest !!
>

I spent one summer on the pit crew of a roundy-round racecar at our local
track.  Saw this:  No thermostat, car definitely overheated.  Install restrictor
plate in water outlet, car ran cool.  Their solution was to pick the right
diameter restrictor to allow engine to operate at a desired temp on a particular
day.

I'll probably get scalded for this one, but I think that removing the t-stat
actually can allow the water pump to cavitate, and possibly cause a pressure
difference between hot engine and cool (relatively) radiator which prevents
coolant from circulating.  While it may seem like I'm grasping for straws, I've
seen something like this in my work many times.  A car comes in with the temp
gauge on WAAYHOT but there's no pressure in the system.  The coolant level is
very low, so someone grabs new coolant to add to the system.  They can put in
one or two quarts before it starts overflowing, and the gauge never drops.
Engine's hot and running, thermostat's wide open, coolant's at the top of the
tank. But if you shut the car off, let it cool for an hour or so, restart it,
and immediately reach for the bucket of coolant, you can add a bunch and the car
never overheats.


> At this point, I pronounce the ads by the rad makers "HOKUM".  Now,
> someone prove me the idiot that most have long suspected  ;-)
>
>

All ads are hokum.  Buy my book to find out why :-]

> Tom Cloud
>
>    Warning, dates in calendar are closer than they appear !