Crazy Heat

bulachip · 06-23-2006, 11:02 AM

So I had a problem not being able to control the temp of the air coming out of my vents. It turned out that the control device was broken it was a very expensive part so my local shop helped me out and put a simple valve device on. Now I am able to reach in the engine compartment and manually switch the air from hot to cold. However, I find that when I turn it all the way to cold my car overheats? If I keep it so just a small amount of heat is coming through the vents I am ok but this sucks in the 90 degree weather!!
Any suggestions?

SoCal Driver · SoCal Driver's Garage

Expensive? Valve is about $25. The cable bracket behind the console is about $35.

bulachip · 06-23-2006, 01:18 PM

Where can I get the correct Valve. If I install the valve can I just move it manually so i do not have to install the cable. I am not sure if i could manage removing the Dash board

Razorback1980 · Razorback1980's Garage

Put it back the way it was designed. Nothing on the early years was expensive. Sounds like you need a new mechanic that knows how to work on your car.

SoCal Driver · SoCal Driver's Garage

If you are in the unfortunate position of having to pay a mechanic you will find their hourly rates a definite budget buster. True for most cars. More true for any Porsche -- even if it is more an mix of Audi and VW.

This is why many learn to fix it themselves or become sufficiently knowledgeable so as to NOT let the mechanic screw them.

The manual vave #944-572-085-02-M53 is $18 at Pelican.

Razorback1980 · Razorback1980's Garage

Still seems weird though the valve would make it overheat. I don't think putting the original valve back in there will stop that from happening. You could until you get this figured out bypass the heater core altogether. But the key is you need to figure out why it's overheating when the valve is closed as I don't think this should happen. I've never had a heater control unit apart so I don't know if the amount of heat coming into the car is controlled by an air flap or the amount of hot water flowing through the heater core. If it's controlled by the amount of hot water going through the heater core, this definitely shouldn't happen no matter which valve is in place. I don't have an early model and I'm not sure if the laters are different designs or not. I'll have to check into the manual and see how the coolant flows but usually the heater is a secondary path and a primary path cools the engine.

carsonmx114 · 06-24-2006, 07:44 PM

sounds like your car is using the heater core as a radiator, maybe your thermostat is stuck closed.

bulachip · 06-25-2006, 11:17 AM

I Have been playing around with the valve and it is now blowing cold air only and the car does not seem to be overheating. I also cleaned out a bunch of leaves from the rad so that could be a big help! Anyway I am learning the hard way that not all shops are great!!

sedonablue · 06-26-2006, 11:19 PM

I'm having the same problem with my 1988 944, and it gets hotter than hades itself in Texas. Is this just a simple changeout of the heater core valve - or - would changing out the thermostat be my first course of action? A/C was working perfectly and then kaboom no cold air with heat coming on even with the A/C turned off.