Spider Heater Valve Repair (Was: Re: 84 spider heater (intermittent))

[Rodney Tidwell <rodneygt@xxxxxxxxxxx>]

Hi all,

Last week I posted about a problem with my spider where the heat worked
somewhat until the car was completely warmed up.  But, then, the hot air
would cool.

Warren Howard reminded me of some earlier digests that had discussed a
"rubber gasket in
the valve control [which when] aged, . . . would swell up.  Then the
natural heat expansion from turning on the heater would cause the gasket
to swell [even more] choking off the supply of water going to the heater
core."

Bruce Giller posted also telling me that it was likely my heater valve
was shot.  Bruce also provided me with some great advice for testing,
locating and removing the heater valve.

Others also offered me advice.  I appreciate that all of you took the
time to respond.

Now, let's get to the subject line.  Last Thursday or Friday after
receiving Bruce's & Warren's replies, it was too late for me to order a
valve and have it before the weekend (I always get a kick when someone
tells me to go to my local alfa dealer as if such an entity existed - in
my case, a  700 to 1000 mile round trip).  Anyway, I wrote Bruce (off
digest) inquiring as to whether or not I would be able to use a
"universal" heater valve (you know, basically, a little pipe with an
opening and closing door - like in a milano).  He said no and explained
why.

Basically, the spider heater valve is a very compact device designed to
fit in a small area.  The fittings form a right angle, but, while one is
for a heater hose, the other bolts to the heater core. It is plastic and
works via diaphragm opened and closed by a spiraled rod connected with a
piece of rigid linkage to a bar operated by the heater cable.  BTW, on
the spider, the heater valve controls how much coolant exits the heater
core.

I understand that the valve may be a bear to remove on '86+ spiders with
air (there were interior changes in '86, including the little shelf
below the steering column - don't know how much, if any, difficulty this
adds).  It was not that difficult (if you're a contortionist :-) ) to
remove on my '84 spider which has a/c .  I removed the valve from my
spider twice this weekend (2nd time to adjust linkage) and found the
minimum items that can be removed to complete the task

Procedure for removal:
1)Place an old towel under the accelerator covering about the top right
1/4 of the driver's side floorboard (this will catch the few ounces of
coolant you will lose)
2)Put a drop light, 10mm wrench, 10 mm socket, 6mm (I think) socket,
ratchet wrenches, various extensions, a u-joint for the 10mm socket and
a standard screwdriver on the driver's side (U.S.) floorboard.
3)Locate the heater housing (move the defrost/floor vent cable up & down
- - you'll be able to see the floor vent open and close)
4)Remove the driver's side defrost duct from the heater housing (just
above the floor vent, you'll see a black plastic piece of duct work
attached to the heater housing - remove the two small bolts at the
bottom - I believe the bolts have 6mm heads, you'll have to check - the
top of the defroster duct is not bolted, it is held under a lip, just
pull)
5)Remove the rigid plastic duct from the rubber duct (the duct work you
removed from the heater housing in step 4 is connected to the defrost
vent with a piece of flexible rubber ducting)
6)Locate the heater valve (you'll probably have to get on your back
under the steering column - The heater valve protrudes from the heater
housing just above the piece of plastic duct you removed in step 4)
7)Remove the heater hose from the heater valve (use your screwdriver to
loosen the heater hose clamp, then pull the heater hose from the outlet
on the heater valve)
8)Free the linkage on the heater valve (the heater lever located on the
console is connected to a lever on the side of the heater housing via
cable, the lever is connected to the heater control valve with a piece
of rigid linkage, the leg bone's connected to the thighbone. . .anyway,
there is a little spring keeper which holds the rigid linkage on the
lever - pull the spring off to free the rigid linkage -the screwdriver
may come in handy here)
9)Remove the heater valve from the heater housing (two 10mm nuts secure
the heater valve - remove them - you'll probably be able to use the
socket on the outside nut - you'll probably only be able to use the
wrench on the inside nut - you'll now be able to work the valve off of
the two studs)
10)If you have a new valve, reverse the procedures to install.  If you
don't, read on.

If your valve will not open enough to allow easy flow, it may be
possible to repair it (at least temporarily).

Procedure to possibly repair the valve (it has worked for me):

1)Drill out the four rivets (when you inspect the valve you'll see that
the two halves are held together with four copper rivets)
2)Seperate the two halves (it just pops apart)
3)inspect the diaphragm ( the problem with mine was that the rubber had
began to disintegrate - a layer of the rubber diaphragm had become
porous much like a sponge - if you've ever had a leaky toilet that
needed a new flapper valve, you'll know what I'm talking about - the
diaphragm was taking up more space within the housing than it used to,
thus, cutting off coolant flow even when "open")
 4)Remove the bad layer of rubber from the diaphragm (use 220 grit
sandpaper or finer until you reach a "good" layer of rubber)
5)Put the valve back together (use four 6/32x1/2 bolts and nuts in place
of the old copper rivets - if you can blow through it now, you're
probably in good shape)

Well, maybe someone can use the procedure sometime.

Thanks all,

Rodney G. Tidwell
McComb, MS

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