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[christky@erols.com]

US, 1990 Jaguar XJS V12 Convertible, 5.3 

How about the following issue? 

I believe that the hot air remaining and circulating in the engine
compartment has nothing to do with the XJS' s overheating problem.  I have
seen a lot of people discussing this, but I do not think this is the cause.
The hot air does not eskape from below because it is ligher than cold ar and
ends up high in the engine compartment.  The motion of the car will suck it
out from underneath but this will not help cool the car.  To prove my point,
if the car was designed to get rid of the hot air from the engine
compartment the Jaguar Engineers would have made vents on the cover of the
engine for hot air to rise out.  Finally, they would have made the fans work
the other way around, i.e. shoot hot air out rather than suching it in.  

What I know about cooling is that it is the radiator that is doing all the
work.  Air should circulate through the radiator for the cooling process to
take place.  Whether that air remains inside the engine compartment or
eskapes does not add up to the cooling process.

I would like to add to the crazy ideas I have just read on the List about
Emergency Cooling: 
I am putting two small fans in front of the radiator anyway - it is a matter
of days for the job to finish - and they will be wired so that they throw
air right AT the radiator.  Finally, I will redirect the windscreen washers
to spray water to the front of the radiator as well.  This will happen every
time I press the washer switch from the inside of the car, or perhaps by an
automatic electronic circuit that I will design.  I will have to use a timer
to wait a number of seconds between sprays.  The combination of water
droplets/ mist and the fans, will cause a cooling effect much like on the
human body when wind blows sweat away.  Water will evaporate and will cause
maximum cooling on the front face of the radiator.  Not only the air stream
from the new fans will cool down due to this, but also the front face of the
radiator like I said before.  Thus, according to my theory I mentioned
earlier for the radiator alone being responsible for cooling, this will
dramatically lower the operating temperature of the car rather than
bothering to get rid of the hot air from the engine compartment.

Does anyone think it is going to work for emergency cooling?  The garden
hose idea has been performed on my car, but it requires that the water is
cold.  Sometimes, the brake system/ electronics inside the engine
compartment heat up together with the rest of the engine parts and the
brakes/ antilock give me red/ yellow warning/ hazard lights.  After that,
the brakes lose their power assist and I have difficulty stopping the car.
There is also a mild vibrating feeling on the brake petal when this
situation arises and the normal brake pumping feeling vanishes.  From the
outside, the brake system makes a buzzing sound as well.  I use the hose to
cool the brake system down locally.  And it works!  It must me heat- related
then.  I did check for any leaks in the brakes, I did maintainance, I did
change brake pads, as well as I did bled the brakes.  It must be the
electronics that heat up and lose their correct values temporarily.    
  
Thanks,

Chris,
1990 Jaguar XJS V12 Convertible, 5.3

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