[DeTomaso] Cabin heat question

[MikeLDrew at aol.com]

In a message dated 2/17/17 9:05:35 PM, fred at creekspeak.com writes:


I have read the different problems with unwanted heat in the Pantera cabin. 
I heard the console kick panels need to be shortened, one or more of the 
control levers are backwards, and a hardware store valve is needed to shut off 
the water to the heater. What is the real solution? When I turn on the fan 
it blows hot air even with all 3 levers to the left. I can turn on th AC 
compressor all the way with the fan and it will blow cool, but that isn't a 
good solution. Can someone please EMAIL me with directions so I can print it 
out easier. As usual, Thanks for your time and incredible expertise.


>>>Fred,

It's time to shed some light on all of this, as it can be confusing and 
there is a lot of misinformation out there.

I've never heard of shortening the console kick panels?   I don't 
understand what that could possibly achieve, but would be interested to know the 
story?   The kick panel on the driver's side is intrusive against the gas pedal 
and there is much to be gained by securing it to the center chassis 
structure with a sheetmetal screw and fender washer, but that's not a cabin heat 
issue.   So please elaborate and tell us what you've heard about this?

Heat pours into the cabin from three distinct sources:

1)   The heater itself
2)   The firewall
3)   The center tunnel

I'll address each of them in turn.

1)   The stock heater control valve was likely a standard European Ford 
part, although I don't know the source.   It might have come from an industrial 
product such as a Ford transit van, or perhaps something else?   It's diff
icult to know, because the valve is mounted to a bracket and sold as an 
assembly, and that assembly has a Pantera-specific part number.

All Ford heater valves, from just about any Ford you can name, have the 
same number, it's 18495.   If you do a Google image search on "18475-A" you 
will see a million different valves, all of them wrong for the Pantera.   The 
prefix sets out the specific Ford model the valve is used in.   The original 
Pantera part number is D16Y 18495-A (D16Y is 1971 spec), in the 1972 Ford 
parts book (which most people have never seen--I only have a scanned copy).   
The later, orange-colored parts book has an updated revision part of D36Y 
18495-A (from 1973).   I don't know what the difference is between the two 
valves however.   I have two of the latter valves in the original Ford boxes, 
destined for my and Lori's Panteras (someday).

Anyway.   The stock valve is a plunger affair, as opposed to a rotary, 
ball-style valve.   Moving the lever moves a plunger in and out which varies the 
amount of water that flows through the heater core (and in theory, blocks 
it completely when it is fully shut).   The odd thing about it is that it 
doesn't just have a single input and single output, as you might expect.  
Instead, it has provisions to be threaded to a metal pipe which comes out of the 
heater core, as well as provisions for TWO hoses.   The parts book shows 
only one of those two hose connections being used, so I truly have no idea 
what's going on with the other one.   Perhaps somebody who has a highly original 
Pantera can shed some light on the plumbing scheme?

The seals in those valves can break down, and they can leak, so that the 
heater is always 'on' even when the lever is closed.   The valves can also 
freeze in position if they aren't actuated periodically.   Many Panteras I've 
seen have had their stock valves replaced with generic one-hose valves, 
readily available at any parts store.   These probably seal better, but they 
require far greater effort to actuate, and can often overwhelm the relatively 
feeble stock control cable and lever (particular the plastic lever in the 
later cars--the early cars used pot metal levers and it's not uncommon to find 
later cars with broken-off heater valve levers).

Lori's Pantera has such a valve installed (by a previous owner) and it's 
almost impossible to move.   In practice, we just keep it in the 'on' position 
all the time….

…which leads us to the first 'fix', one commonly performed and likely found 
on the majority of the Panteras out there.   The heater is supplied by two 
hoses/pipes; an outlet on the front of the engine block, and an inlet on the 
water pump.   In practice, most people install manual shutoff valves in the 
engine bay on both inlet and outlet hoses, or alternately, just bypass the 
heater entirely and run a hose directly from the engine outlet to the water 
pump inlet.   

Either of these schemes is desirable for several reasons, not the least of 
which is safety.   If the hoses from the metal pipes in the center of the 
cabin to the heater matrix have never been changed, they are a genuine danger 
and can lead to all sorts of catastrophes if one bursts.   Just in the past 
few days you have heard first-hand testimony from owners (including Jackie 
Stewart) who experienced a combination of burns and fright when a heater hose 
burst and the cabin filled with steam.   What you haven't heard is the 
testimony from owners who literally wrecked their cars as a result.   One 
well-known person was running his car at a dragstrip in Dallas, and managed to 
find the wall and smash the hell out of his Pantera when the hose burst and 
high-pressure scalding water burned his feet and blinded him.

Yow.

Besides safety, addressing your original query, the metal pipes that carry 
water to and from the heater will radiate heat into the cabin, especially if 
the heater valve is leaking.   Preventing water from entering those pipes 
(either through the use of external shutoff valves or a bypass arrangement) 
goes a long way towards reducing cabin heat.

In Lori's car, we keep the in-cabin valve open all the time, and the 
external valves closed.   On those rare occasions where heat is desired, it's a 
simple matter to open up the external valves, in which case the heater 
performs quite nicely, as intended.   My car has the heater completely bypassed, 
but one day I do hope to plumb it and get it working properly.

If you still have an original plunger-type valve, hopefully it still moves 
freely.   If you are feeling ambitious, you can disconnect the inlet and 
outlet hoses from the engine, close the valve, and then test using compressed 
air or vacuum to see if it leaks.   If so, Larry Stock has heater valve 
rebuild kits available (and, I presume, will sell a rebuilt stock valve on an 
exchange basis).

2)   There is an awful lot of heat right behind you in the form of a 
hulking great engine.   There is not much between you and that engine except for a 
steel firewall and some very rudimentary heatproofing material, and the 
upholstered fiberglass interior back panel.   There is much to be gained by 
adding additional insulating material between the steel firewall and the 
fiberglass panel.   Actually, if one is making the effort, it makes sense to kill 
two birds with one stone and also install a layer of Dynamat or similar 
vibration-absorbing mat.   While this won't do an awful lot for heat (it does 
supposedly do something), it will dampen vibration and reduce perceived noise 
in the cabin.   

With a layer of Dynamat applied to the firewall, then one or more layers of 
heat insulation can then be applied atop it.   There is plenty of airspace 
between the firewall and the back side of the fiberglass interior panel, 
which can be safely occupied by heat insulation.   More is always better here, 
and there is absolutely nothing to be lost by doubling or even tripling up 
on such insulation.

3)   Similarly, the center tunnel is a prime source of radiant heat, not 
only from the heater pipes, but also (and more significantly), from the 
undercar pipes that transmit water to and from the radiator.   If you ever drive 
your Pantera with the center interior console removed, you will find the 
center steel box structure can become too hot to touch!   This is another area 
that benefits from the Dynamat/heat insulation treatment.   Even if the 
heater pipes are blocked off or disconnected, enough heat from the radiator pipes 
makes its way into the cabin that it is worthwhile to insulate the center 
box structure as much as possible.

Finally, it's worth mentioning that any and all holes in the firewall 
should be hunted down and blocked off.   I was once riding in a friend's Pantera, 
and my right elbow was almost burned by hot air blowing around the back 
panel and onto the back edge of the passenger door.   It turns out he had a 
hole in the firewall, and very hot air was blasting into the cabin, wholly 
unnoticed by the owner because it was on the passenger side.   We removed the 
interior panel to investigate and found some unused access holes for A/C lines 
that had been removed.   Plugging those holes made a huge difference in 
cabin comfort immediately.

FWIW, years ago Gray Gregory and I shared my Pantera on the drive to the 
POCA Fun Rally.   Crossing the Sierra Nevada mountains, we had to pull over 
and stop to put on jackets because my cabin was so cold!   So believe me, you 
don't need to suffer with cabin heat.   Fortunately it's relatively easy and 
inexpensive to eliminate it almost entirely.

Good luck!

Mike

-------------- next part --------------
   In a message dated 2/17/17 9:05:35 PM, fred at creekspeak.com writes:
   I have read the different problems with unwanted heat in the Pantera
   cabin. I heard the console kick panels need to be shortened, one or
   more of the control levers are backwards, and a hardware store valve is
   needed to shut off the water to the heater. What is the real solution?
   When I turn on the fan it blows hot air even with all 3 levers to the
   left. I can turn on th AC compressor all the way with the fan and it
   will blow cool, but that isn't a good solution. Can someone please
   EMAIL me with directions so I can print it out easier. As usual, Thanks
   for your time and incredible expertise.
   >>>Fred,
   It's time to shed some light on all of this, as it can be confusing and
   there is a lot of misinformation out there.
   I've never heard of shortening the console kick panels?  I don't
   understand what that could possibly achieve, but would be interested to
   know the story?  The kick panel on the driver's side is intrusive
   against the gas pedal and there is much to be gained by securing it to
   the center chassis structure with a sheetmetal screw and fender washer,
   but that's not a cabin heat issue.  So please elaborate and tell us
   what you've heard about this?
   Heat pours into the cabin from three distinct sources:
   1)  The heater itself
   2)  The firewall
   3)  The center tunnel
   I'll address each of them in turn.
   1)  The stock heater control valve was likely a standard European Ford
   part, although I don't know the source.  It might have come from an
   industrial product such as a Ford transit van, or perhaps something
   else?  It's difficult to know, because the valve is mounted to a
   bracket and sold as an assembly, and that assembly has a
   Pantera-specific part number.
   All Ford heater valves, from just about any Ford you can name, have the
   same number, it's 18495.  If you do a Google image search on "18475-A"
   you will see a million different valves, all of them wrong for the
   Pantera.  The prefix sets out the specific Ford model the valve is used
   in.  The original Pantera part number is D16Y 18495-A (D16Y is 1971
   spec), in the 1972 Ford parts book (which most people have never
   seen--I only have a scanned copy).  The later, orange-colored parts
   book has an updated revision part of D36Y 18495-A (from 1973).  I don't
   know what the difference is between the two valves however.  I have two
   of the latter valves in the original Ford boxes, destined for my and
   Lori's Panteras (someday).
   Anyway.  The stock valve is a plunger affair, as opposed to a rotary,
   ball-style valve.  Moving the lever moves a plunger in and out which
   varies the amount of water that flows through the heater core (and in
   theory, blocks it completely when it is fully shut).  The odd thing
   about it is that it doesn't just have a single input and single output,
   as you might expect. Instead, it has provisions to be threaded to a
   metal pipe which comes out of the heater core, as well as provisions
   for TWO hoses.  The parts book shows only one of those two hose
   connections being used, so I truly have no idea what's going on with
   the other one.  Perhaps somebody who has a highly original Pantera can
   shed some light on the plumbing scheme?
   The seals in those valves can break down, and they can leak, so that
   the heater is always 'on' even when the lever is closed.  The valves
   can also freeze in position if they aren't actuated periodically.  Many
   Panteras I've seen have had their stock valves replaced with generic
   one-hose valves, readily available at any parts store.  These probably
   seal better, but they require far greater effort to actuate, and can
   often overwhelm the relatively feeble stock control cable and lever
   (particular the plastic lever in the later cars--the early cars used
   pot metal levers and it's not uncommon to find later cars with
   broken-off heater valve levers).
   Lori's Pantera has such a valve installed (by a previous owner) and
   it's almost impossible to move.  In practice, we just keep it in the
   'on' position all the timea|.
   a|which leads us to the first 'fix', one commonly performed and likely
   found on the majority of the Panteras out there.  The heater is
   supplied by two hoses/pipes; an outlet on the front of the engine
   block, and an inlet on the water pump.  In practice, most people
   install manual shutoff valves in the engine bay on both inlet and
   outlet hoses, or alternately, just bypass the heater entirely and run a
   hose directly from the engine outlet to the water pump inlet.
   Either of these schemes is desirable for several reasons, not the least
   of which is safety.  If the hoses from the metal pipes in the center of
   the cabin to the heater matrix have never been changed, they are a
   genuine danger and can lead to all sorts of catastrophes if one
   bursts.  Just in the past few days you have heard first-hand testimony
   from owners (including Jackie Stewart) who experienced a combination of
   burns and fright when a heater hose burst and the cabin filled with
   steam.  What you haven't heard is the testimony from owners who
   literally wrecked their cars as a result.  One well-known person was
   running his car at a dragstrip in Dallas, and managed to find the wall
   and smash the hell out of his Pantera when the hose burst and
   high-pressure scalding water burned his feet and blinded him.
   Yow.
   Besides safety, addressing your original query, the metal pipes that
   carry water to and from the heater will radiate heat into the cabin,
   especially if the heater valve is leaking.  Preventing water from
   entering those pipes (either through the use of external shutoff valves
   or a bypass arrangement) goes a long way towards reducing cabin heat.
   In Lori's car, we keep the in-cabin valve open all the time, and the
   external valves closed.  On those rare occasions where heat is desired,
   it's a simple matter to open up the external valves, in which case the
   heater performs quite nicely, as intended.  My car has the heater
   completely bypassed, but one day I do hope to plumb it and get it
   working properly.
   If you still have an original plunger-type valve, hopefully it still
   moves freely.  If you are feeling ambitious, you can disconnect the
   inlet and outlet hoses from the engine, close the valve, and then test
   using compressed air or vacuum to see if it leaks.  If so, Larry Stock
   has heater valve rebuild kits available (and, I presume, will sell a
   rebuilt stock valve on an exchange basis).
   2)  There is an awful lot of heat right behind you in the form of a
   hulking great engine.  There is not much between you and that engine
   except for a steel firewall and some very rudimentary heatproofing
   material, and the upholstered fiberglass interior back panel.  There is
   much to be gained by adding additional insulating material between the
   steel firewall and the fiberglass panel.  Actually, if one is making
   the effort, it makes sense to kill two birds with one stone and also
   install a layer of Dynamat or similar vibration-absorbing mat.  While
   this won't do an awful lot for heat (it does supposedly do something),
   it will dampen vibration and reduce perceived noise in the cabin.
   With a layer of Dynamat applied to the firewall, then one or more
   layers of heat insulation can then be applied atop it.  There is plenty
   of airspace between the firewall and the back side of the fiberglass
   interior panel, which can be safely occupied by heat insulation.  More
   is always better here, and there is absolutely nothing to be lost by
   doubling or even tripling up on such insulation.
   3)  Similarly, the center tunnel is a prime source of radiant heat, not
   only from the heater pipes, but also (and more significantly), from the
   undercar pipes that transmit water to and from the radiator.  If you
   ever drive your Pantera with the center interior console removed, you
   will find the center steel box structure can become too hot to touch!
   This is another area that benefits from the Dynamat/heat insulation
   treatment.  Even if the heater pipes are blocked off or disconnected,
   enough heat from the radiator pipes makes its way into the cabin that
   it is worthwhile to insulate the center box structure as much as
   possible.
   Finally, it's worth mentioning that any and all holes in the firewall
   should be hunted down and blocked off.  I was once riding in a friend's
   Pantera, and my right elbow was almost burned by hot air blowing around
   the back panel and onto the back edge of the passenger door.  It turns
   out he had a hole in the firewall, and very hot air was blasting into
   the cabin, wholly unnoticed by the owner because it was on the
   passenger side.  We removed the interior panel to investigate and found
   some unused access holes for A/C lines that had been removed.  Plugging
   those holes made a huge difference in cabin comfort immediately.
   FWIW, years ago Gray Gregory and I shared my Pantera on the drive to
   the POCA Fun Rally.  Crossing the Sierra Nevada mountains, we had to
   pull over and stop to put on jackets because my cabin was so cold!  So
   believe me, you don't need to suffer with cabin heat.  Fortunately it's
   relatively easy and inexpensive to eliminate it almost entirely.
   Good luck!
   Mike