conate

Went to replace HCV and found PO had already wired arm in closed position. It was not fully closed but that was not why my feet were on fire. Found the weld on the firewall was cracked in the area where torque tube goes back to transmission. U shaped weld. I was able to seal most of it with some high temp RTV and now the heat has dramatically decreased but there is still some coming through. I will address when car cools.
I installed new HCV and small hose to it. Started car and let it come to temp. Turned on AC and HCV did not close. When should the HCV close? I suspect its a vacuum issue from control valve. Checked operation of all the interior vents and all are working as they should.

928porschemangreg

Follow the vacuum line to the right to a 3 way, then it goes off to another 3 way. All those plastic lines tend to pull out of the rubber connections. reset them in and put little wire ties around them to hold them in. My vacuum increased in this area after I did this. I put cardboard over the engine, then a blanket, and lay right over the top, in order to see in that area.

chitown928s4

Try moving the arm that made a difference with my sitch. Before the metal tube was hot after moving the arm it got could. Cant remember which way. Run the AC and youll figure out.

conate

Followed the lines all connected. PO was meticulous with everything mechanical on the car. When I get the chance going to pull console and check actuators. Probably tomorrow....seems like I am waking up at 1 AM and going to garage for an hour or two of work ......

86gtvert

Is it possible to loop the coolant hoses that come into the cabin/heater core? I understand this will eliminate the possibility of heat (short term fix) but I dont plan on driving the car during the winter months anyway. My major concern with this theory is the affect it will have on the running temperature of the car. By eliminating a portion of the cooling system, would this not raise the engine temperature?

I am just trying to brainstorm "outload"

conate

New update...heat is coming through floor from catalytic converter. Checked the cats and the heat shield is on. Both cats are relatively new. The cats ARE the MAIN heat generators on my floor. I will have the exhaust system checked out ....there is a chance the cats are bad. What an adventure!!!

OTR18WHEELER

save this link in your favs
http://www.nichols.nu/cat05.htm

conate

Link saved...going to have to get a dedicated laptop agian....had one for my 2000 VW Jetta TDI...

86gtvert

**Update on my situation**
So, with the help of my good friend OTR18WHEELER, yesterday I solved my unwanted cabin heat issue. Here is what we did:
Step 1: remove the airbox (thus exposing the HCV and hoses)
Step 2: Cut the hose going to the input side of the heatercore (top DS on the firewall)
Step 3: remove the HCV and the small hose going back into the back of the block (PS)
Step 4: attached the newly cut heater core supply hose, from the front of the block (from step 2) to the neck that was now exposed after removing the HCV and the small hose.
Step 5: Using (2)3/8" x 1/2" socket adapters (because they have smooth side walls) and new hose clamps, we plugged off the remaining hose that would supply the heater core and also the hose that comes out of the heater core.
Step 6: Started the car and let it get up to temperature to check for leaks. In order for the car to maintain idle and continue to run, we had to use the air filter to cover the air intake screen (not 100% sure what it is actually called). After we were certain of no coolant leaks, we reassembled the air box and reinstalled. Drove the car about 10 miles (keep in mind, it was already at temperature).
Step 7: Parked the car and double checked for coolant leaks. NONE FOUND at this time.
- So before I get bashed for cutting the upper heater core hose, here was our theory:
This would be the only 100% fool proof way to identify a faulty HCV was allowing the heat to come in the cabin thru the vents. Additionally, when I get a new HCV, I can simply couple the upper hose back together and reinstall the HCV and the short hose, thus returning it to "factory" condition. For the record, as you would surmise, this did eliminate the heat coming in the car thru the vents and also the capability of the car producing heat which in my situation really does not matter. The car ran just a hair above the "mid range" on the temp gauge.
On a side note, this also allowed me to confirm both of my cooling fans are working and roughly when they engage (which happens to be as the needle on my temp gauge crosses the "half-way" point).
So to summarize, to purists, I'm sure I have committed a mortal sin however in my garage, it is simply a means of trouble shooting based on the tools and expertise that I have at the time. Feedback welcome...

Imo000

The valve is leaking and letting hot coolant into the heather core.

Alan

Looks like you cut the vacuum hose - that doesn't help anything because the heater valve default position (no vacuum) is open - allowing hot coolant flow. You need to tie the actuator arm for the ball valve into the activated position.

Alan

86gtvert

Actually, that is a step I forgot to mention. We actually capped the vacuum line that runs from the splitter to the bottom of the HCV. Im fairly sure the line had not been cut prior to us removing the HCV yesterday.

Alan

The hot water valve closes only due to temperature settings. To ensure its closed select the minimum temperature on the slider.

Even in AC mode the closed loop climate control is active (e.g. the head unit will be trying to achieve a set absolute cabin temperature), for most of the temperature slider range the hot water valve will likely be open. If relative to the current ambient you have selected a much lower temperature the water valve will go off. The climate control closed loop mode is interrupted at the max cold slider end AND the max hot slider positions.

In max cold it will close the water valve and just cool at the maximum possible rate regardless of cabin temperature. Max hot guarantees the water valve is open & will heat at the maximum possible rate regardless of cabin temperature.

The AC mode 'on' affects how cool you can go and how quickly you will cool but it doesn't change how temperature is regulated - except in the max cold condition.

Under certain cooling conditions (including max cold) the comb flap (heater core bypass) is activated - this provides a more direct (=> colder) path from the AC evaporator to the console & door vents

Alan