[xj] heater control valve rerplacement

XJ
1

I have a '85 XJ6 with a frozen heater control valve. I got a
replacement from Welsh with pn c-41051 and it is not the
same. The one in the car is two pieces with the valve part
of the bracket fastened to the back part of the bracket
which is fastened to the firewall. The replacement haw a
one-piece bracket.

The two 5/16 hex screws to the firewall do not loosen when
turned from the front side - like they might have locking
nuts on them. I can’t access the rear side of the firewall
to remove the valve.

In addition, there are two philip screws with tiny lock nuts
holding the valve side of the bracket to the firewall side
and one has the screw head on the front and the other on the
rear.

Is there another valve with a bracket similar to the one on
the car?

How can the firewall screws be removed - i.e. how can the
nuts be accessed?

Bruce Cunningham–
touchthiscar
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2

In reply to a message from touchthiscar sent Sat 18 Aug 2012:

You’ll probably find that many people on this forum have
gone with the GM style plastic replacement valve that is
listed in the parts interchange list - I know I have. It’s
way cheaper and light enough that it needs no bracket.–
Pjprofili
Marietta, GA, United States
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3

In reply to a message from Pjprofili sent Sat 18 Aug 2012:

ours is an '85 Series 3 with a normally open vacuum
controlled valve - my understanding is the GM valve is
normally closed and is for the Series 1 only–
Bruce Cunningham
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4

In reply to a message from touchthiscar sent Sat 18 Aug 2012:

Bruce,

I can’t remember if it is Normally Closed or Open, but I
have the Gm plastic valve in my Series 3 and it works fine.

Best,
Aristides–
The original message included these comments:

In reply to a message from Pjprofili sent Sat 18 Aug 2012:
ours is an '85 Series 3 with a normally open vacuum
controlled valve - my understanding is the GM valve is
normally closed and is for the Series 1 only

–
Aristides Balanos, 1986 XJ V12,VDP - www.e-psychi.com/jaguar
Roussillon, Provence, France
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5

touchthiscar wrote:

I have a '85 XJ6 with a frozen heater control valve. I got a
replacement from Welsh with pn c-41051 and it is not the
same. The one in the car is two pieces with the valve part
of the bracket fastened to the back part of the bracket
which is fastened to the firewall. The replacement haw a
one-piece bracket.

The first step is to verify that the valve works as intended, Bruce…

…ie, verify that it is indeed ‘open’ with no vacuum, and duly closes
when vacuum is applied - being fully functional and the right type…

The OEM did not chnage, but aftermarkets may come in various guises -
the GM mentioned by another lister is one of them. Which may be
substituted leaving the original in place - or forcefully removed.

If captive nuts were indeed used and no longer ‘captivates’, there is
certainly a problem, particularely if you cannot remove the bracket
either. Loose captive nuts must be accessed and clamped from the rear -
there are no other ways. However, nobody has mentioned this problem in
replacing the water valve…?

Frank
xj6 85 Sov Europe (UK/NZ)>The two 5/16 hex screws to the firewall do not loosen when

turned from the front side - like they might have locking
nuts on them. I can’t access the rear side of the firewall
to remove the valve.

In addition, there are two philip screws with tiny lock nuts
holding the valve side of the bracket to the firewall side
and one has the screw head on the front and the other on the
rear.

Is there another valve with a bracket similar to the one on
the car?

How can the firewall screws be removed - i.e. how can the
nuts be accessed?

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6

In reply to a message from Frank Andersen sent Sun 19 Aug 2012:

Bruce:

My car’s OEM heater valve was gone when I got the car. No bracketry
left either. The plastc unit is light enough to neeed no suppot
other than the hoses. It does it’s job.

I think the nuts are in the airinteke plenum under the grill in
front of the woindshield. Veeery carefully remove the screen and
washer jet to get to them.

I’d consider leaving the bracket in place or cutting it off.

Carl–
The original message included these comments:

I have a '85 XJ6 with a frozen heater control valve. I got a
replacement from Welsh with pn c-41051 and it is not the
same. The one in the car is two pieces with the valve part
of the bracket fastened to the back part of the bracket
which is fastened to the firewall. The replacement haw a
one-piece bracket.

–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

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7

In reply to a message from cadjag sent Sun 19 Aug 2012:

Does someone have a GM part number for the3 substitute valve?–
Bruce Cunningham
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8

In reply to a message from touchthiscar sent Sun 19 Aug 2012:

Bruce…

At the top of the page, there is a link titled parts
interchange… There, I found this info:
‘’ Heater Control Valve–the late-model plastic type is
available from Pep Boys, et al. One brand name is Factory
Air, Part No. 74803. This black plastic is good looking and
definitely superior to a metal type. The reference is to a
Series III XJ6 or XJ40. Part is about $12 US.’’ Henry Fok:
‘‘The difference between the 74612 and the 74803 is in the
size of the vacuum hose fitting. I unfortunately cannot
recall which one I bought for my 84 S3 - believe it was the
74612- but one has a fitting for a much larger diameter
vacuum hose than the other. Compare it to your car before
buying.’’

There are a couple of other references, that may be worth
checking out…
However, if you have the part from Welsh on hand, I’m sure
you have what you need…
As Carl says, to access the nuts on the bracket, all you
need to do is remove the fresh air vent (carefully), and
they are easy to get to…

Otherwise, leaving the old one in place and adding another
contraption will likely just add clutter to the already busy
engine compartment…

Cheers!
David
www.EverydayXJ.com–
The original message included these comments:

Does someone have a GM part number for the3 substitute valve?

–
84 XJ6 (Driver) 89 XJS Convertable… Parts cars piling up.
Rockwell, NC, United States
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9

In reply to a message from DavidBoger sent Sun 19 Aug 2012:

There is an art to removing the grill over the fresh air vent - I
probably broke a dozen of them trying to perfect it. You’ll need a
SwingHook SW10 from Ulman Devices. Hook it under the fins, right
close to where the pin goes down - you’ll have to use the swinger
(as pry) to gently work your way over to the sweet spot where the
pin is. You’ll know by its resistance to pulling as you get closer
to the pin. Once you get up close as possible, then pry with all
your might, but don’t pull it up more than a half inch! Go do the
same on the other side, et Voila!–
The original message included these comments:

As Carl says, to access the nuts on the bracket, all you
need to do is remove the fresh air vent (carefully), and
they are easy to get to…

–
Ted Macklin/'85 XJ6SIII
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10

In reply to a message from TMack sent Mon 20 Aug 2012:

Yup:

I removed mine to spruce it up. Peeling chrome over yellow plastic
not fitting when contrasted against shining waxed Grsosvenor Brown.

Jagcare III discusses the procedure to remove. I used one of my
home made tools. In this case a slim screwdriver with the last 1/4’’
bent at a 45. I have a bucket of screwdrivers that are past their
primary use. Repurposed into poking asnd levering tools.

The plastic has tiny protuberances as pins. These are pressed into
a mastic in the body work. Odd, but effective. Mine only had one
pin. The grill had no pin and the mastic had never been pierced.

After I scraped away most of the peeliong chrome, I sprayed it with
rattle can aluminum. Looks like a sand casted alloy now!!

I crefully drilled it with my Dremel knock off and inserted a thn
screw, about the size of the remaining pin. Used my farrier nippers
to nip off the screwhead and voila secure metal pin.

Oh, one leg was broken!! I repaired it with Krazy Glue and all is
well.

Some day, I’ll fix the squirter. I know the pump works, I made new
wires and bench tested it! If the issue is in the stalk, bye bye
squirter, or I’ll create a different switching mechanism.

Well, the table project is doing well. Ran out of screws and
shoulders yesterday. Today, I better mend the post securing the
mail box. I got some post menders at ACE yesterday.

They hae a small placcard with kids and their soap box cars. The
real stuff, not the Daddy builts. I’ve dibs on t. Looks just like
my friends and I and our ‘‘racers’’. No slick wheels, just all manner
of spoked ones. As on the tricycles of the day or one looks like
it’s wheels saw duty on a pram!!

Carl–
The original message included these comments:

There is an art to removing the grill over the fresh air vent - I
probably broke a dozen of them trying to perfect it. You’ll need a
SwingHook SW10 from Ulman Devices. Hook it under the fins, right
close to where the pin goes down - you’ll have to use the swinger
(as pry) to gently work your way over to the sweet spot where the
pin is. You’ll know by its resistance to pulling as you get closer
to the pin. Once you get up close as possible, then pry with all
your might, but don’t pull it up more than a half inch! Go do the
same on the other side, et Voila!

–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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11

cadjag wrote:

In reply to a message from TMack sent Mon 20 Aug 2012:

…Some day, I’ll fix the squirter. I know the pump works, I made new
wires and bench tested it! If the issue is in the stalk, bye bye
squirter, or I’ll create a different switching mechanism.

The stalk switch is simply a ground for the washer motor, Carl - which
of course does’t make it failsafe…:slight_smile:

So if there is no motor action in-car one can contort ones body, to
ground the motor at its mounting. If there is action then - the stalk is
the culprit…or the wiring to it…or …or… And if the motor runs,
but there is no squirt, the hose or the squirter itself is clogged, of
course…

Here the washer must work, or one does not get a warrant of fitness -
hence it keeps my body supple…:))

Frank
xj6 85 Sov Europe (UK/NZ)===================================================
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12

In reply to a message from Frank Andersen sent Mon 20 Aug 2012:

thanks especially to Carl Hutchins for pointing out that the
nuts can be accessed under the grille at the base of the
windscreen. Turns out that they are tiny locknuts rather
than captive nuts - but I did find them and replaced the
valve successfully this afternoon.

Thanks also to those who suggested care to not brake the
plastic pins but I did break off one of them and I may fix
that some day but maybe not because the grill seems pretty
secure with only one pin anyway.

The old valve would open and close but it was gummed up and
the available vacuum was not enough to overcome the
resistance. The new one from Welsh works just fine.

Bruce–
Bruce Cunningham
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