Date: Fri, 15 Jan 1999 00:36:31 -0600
Reply-To: Budd Premack <bpremack@WAVETECH.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Budd Premack <bpremack@WAVETECH.NET>
Subject: Re: COLD fresh air leaking (Solutions!)
Content-Type: multipart/alternative;
It seems that many of us (including me) have been troubled by fresh (cold) air leaks in the
heater system. I happen to have a complete (blower, heater core, ducts,
flap doors, etc.) spare heater assembly from an 86 GL sitting next to me.
Examination of it and my van, and a bit of advice from Darrell Boehler have
led me to the following conclusions.
Fresh air coming into the van is supposed to be stopped in two ways. (In a factory fresh van, employment of both of these methods will stop all fresh air infiltration.) The
bottom heat control lever operates a large interior air plenum flap that supplies fresh air
to the rear top ducts. Pushing this lever to full right theoretically
closes this. However, foam around the edges of all of the ducts flaps does
deteriorate, resulting in air leakage even when the flaps are in the closed
position. Repair of these foam edges does require removal of much of the
dash to gain access. This is a project to be avoided unless you have lots
of time and a comfortable (warm) work area.
It should also be noted that if the wires that are attached to the control
levers and run to the various flaps are bent, kinked, or misadjusted, the
flaps will not operate properly, and this can be the sole or contributing
cause of air leakage.
The second way of stopping fresh air is simply to use the thumb knobs on the
two dash air vents. Pushing them up closes those air flaps. They also can
have deteriorated foam edges, but are very simple to remove and repair if
desired.
Fresh air can also leak in if the duct connections to the dash vents are not tight. If the
air leaks out prior to reaching the dash vents, it does no good to close
them. There are 2 1/4 " ducts that go from each side of the center air
assembly to the respective dash vents. They can easily be loose at
either/both ends. This can be resolved by using duct tape and/or radiator
hose clamps, depending upon how anal you are feeling at the moment. Access
to the passenger side duct is simple, just remove the glove box. Access to
the driver's side can be gained from underneath the dash at the vent.
Access to the driver's side at the center air assembly connection can be
done by someone with small hands, if you reach underneath. Being a bit of a
contortionist is also helpful. Alternately, you can remove the instrument
panel, speedometer, etc. (not too bad a job, actually) and approach it from the top. BTW, I had loose hose connections on both sides. These hoses can also have holes in them, which can obviously be repaired with duct tape, or you can replace the hose with an original or make up a replacement from available materials.
If you want to really stop fresh air infiltration, you can stop it at the source, and not have to be concerned about hoses, flaps, and foam edges. Fresh air enters the entire van at the front, right behind the top front grill. Simply remove the grill and you will notice a large plastic mesh which covers the fresh air intake plenum. This can be covered with duct tape, cardboard, or whatever you want. I used cardboard cut to fit, wrapped with duct tape for strength and moisture resistance, and secured to the mesh with more duct tape. Those of us in cold climates should be aware that duct tape does not adhere well if it is applied when it is cold. One answer to this problem is to heat the tape and van front by getting into a warm place for about 30 minutes (which is all it should take to place a cover over the mesh). If this is impractical, try heating the area locally with a portable heater or hair dryer (especially useful if you can get into an unheated
garage that isn't too frigid). Alternately, or in addition to taping, you can secure the cover by using wire to hold it firmly to the mesh and/or surrounding brackets.
After I followed this last approach, my air leak was reduced substantially,
but was still not cured. Then Darrell Boehler informed me that there are
two mice sized round holes, one on each side of the mesh intake cover. So,
this weekend, as the temperature here will exceed 20 F for the first time in
several weeks, I will remove the top grill, locate those two holes, and fill
them with insulation and/or duct tape.
The beauty of the grill approach is that it is simple, quick, and easily
reversible when you again want fresh air, or if you finally get a chance to
pull the dash and fix any deteriorated foam.
These suggestions are not meant to be exhaustive, nor even completely accurate. For example, late 87 and newer vans get heated air from the dash vents, while earlier models do not. These procedures represent my 86 Syncro GL, which obviously has some ductwork/plenum chamber differences from later models.
Another source of cold air is a heater core that is partially/fully clogged. Air in the coolant system also reduces heater output. There are probably other related causes, which I hope other Listees can enumerate.
For those of us with air leaks, let us just remember our bretheren in air cooled vans and buses who often can only dream of warmth. I personally recall the fun of driving my
72 Westy in below 0 temps with a completely non-functional heating system. Remember, it is only two more months until the official start of Spring!
Budd Premack
86 Syncro, 84 GL, 73 Super
Minneapolis, MN (Land of Frozen Waters)
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