DrZ1

I think my HCV is on its way out as hot air blows trought the vents when it is cold ouside. (clip replaced last year and is holding fine).

Also I am loosing coolant, I will try to have it pressure tested. My question is has any one noticed that w/ HCV leak they were having it malfunction and blowing hot.

Also will this valve failing cause the car to run hotter faster, assuming that the resivior fluid is full. I notice my temp climb faster, so if stopping more then 15-20 sec I need to hit my a/c to turn on both fans.

thanks
Steve

xsboost90

probl sucking in air too- air gets hot fast and can fool your gauge if its near the sensor...

Dal Heger

Replace it before it fails and ruins your clutch.

chrly924s

I moved my valve, ala 968, when I did my clutch job this summer. My history w/putting new antifreeze in anything just begged for the valve to blow all over that little window and down into the bellhousing!!!

Zero10

If the rubber diaphram in the HCV fails, then the valve will stay on all the time. If the heater clip inside is okay then you should have very little heat when it is off, and full heat when it is on.
Now, on the other hand if the clip inside fails but your HCV is still good, then you will have an appreciable amount of heat when it is set to heat, and full heat when on

Now, if the plastic body itself fails, then you will be pouring coolant all over the back of the engine. My previous HCV failed in this manner very shortly before I replaced it (i.e. the new one was in the box, and I was pulling into the garage to replace it when it broke).

The HCV should never cause your engine to heat up faster unless it is stuck closed, which it sounds like yours is not.

Step 1: Pressure test coolant system
Step 2: Have somebody inside the car cycle the heat control (hot-cold-hot-cold) and observe if the arm on the HCV moves. If it does, and it is not leaking coolant then your HCV is fine.