When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have a 91 C4 Cab. The floor sill/door channel on the passenger side and the metal brackets on my convertible top get very hot. The heater/Air Con work normally.
There are two potential sources of the heat, the oil cooler line and the heater line that both run through the door sill.
I can disconnect the orange hose that runs from the flapper valve to the heater ducts to see if this is the source of the heat.
My mechanic thinks it is the oil lines are too close to the door channel that is causing the problem.
Your guess/experience please
Joe Perret
Had same issue; my wife's feet would get basically scalded. There's a paper hose that's a PIA to remove that is likely punctured/degraded; hot air is circulated through there regardless of the HVAC setting. It also costs like $30+ and it's literally just a foot and a half of HVAC tubing.
If you remove the carpet/cardboard thing that sits around your OBD input (there are 3 or 4 screws to undo, it's easy), you will see exactly what I'm talking about.
If its not the heater, then check the installation of your oil tank and the lines that run from the thermostat to the oil cooler. Ensure that they have the rubber insulators that keep them isolated from the body.
+1 on the paper hose (see attached pic from mine) - though in my experience, get the original Porsche parts as the driver's side tube is specifically molded at the top end and many aftermarket ones aren't (which make them near impossible to install). Both tubes and assorted screws came to about 100 CHF (in Switzerland, which for Porsche parts is almost free) and the part numbers are:
964 572 528 01
964 572 527 01
PS - Duct tape: not a good solution, as installed by the previous owner of the car.
Thanks all for the inputs - here is what I found so far....
1. The major problem was caused by the "HEATER VENT INSERT" Part #: OEM-96457204301 called a "Insert Bleeding or Insert Ventilation" by Porsche)
. Those are for venting air in and air out, primarily when you close the doors. They are right below the seat belt spools.
If they are bad (mine was melted) they can cause the differential pressure needed to open the flapper valve ("Heat Control Box" 964 572 087 00 (L) ) sending in hot air from the heat exchangers. The heat not only goes into the door sill area, but also air pores through the broken vent ("Insert Bleeding or Insert Ventilation" ) and heats the area behind the panel, in my case where the convertible top fold down,
I removed both sides HEATER VENT INSERT, made a temporary cover plates while I wait for my replacement parts from Pelican, and the big heat problem went away. The door sill on the passenger side get "warm" but not hot to the point I can't hold my hand on it.
2. Next step is to fix the oil cooler lines, which I believe to be the remaining cause. This will be expensive, because the hoses are old and should be replaced while I am in there.
If it's the hose, you can use an aluminum laundry dryer vent hose and custom cut it as needed. I find it a perfect fit and an upgrade from the original part. $15.
@tmistry bringing up an old thread and i have the super hot passenger foot well. i bought silicon hose to replace the ducting on the heat exchangers (from headers) and they work fine. do you have any pics of the passenger side footwell fix?
Found this flap 964.572.043.02 completely melted under the seat belt spool. My servos are now working properly, the flap has a good seal, duct & jubilee clamps are brand new both sides and CCU is set to cold. Haven’t started the car yet since I’m waiting for other parts but my question is:
When the engine is off and no airflow from P2 or P1 on the diagram, what is the “natural” position of the metal flap? “A” or “C” position? I already checked they are not seized. They swing freely. I’m hoping it will dump from the lower exit of the differential pressure flapper Found this melted under the seat belt spool on the passenger side
06-28-2016, 03:07 AM
Hot Passenger Side Floor Sill/Door Channel.
