Randy B

I am posting this for future reference of other users as I searched and could not find the exact cause.

While I am not in single or below 0 digits, it is quite cold here in Orlando for this time of year. Tried using the heat from the AC system for the first time this season and no heat at all. Just cold air.

No fault codes or messages, so I went to all data and looked up some troubleshoot flow charts.

First test was the AC System for a bad actuator on a dampener door and or thermistor out of resistance. I have a NAV system, so to enter the diagnostic mode, you hold the Auto and fresh air buttons simultaneously and turn the key to on without starting the motor. A screen will start on the NAV screen and all items will be tested including every step of the fan and blender doors for all vents.

Since that passed, I checked the radiator level and found the radiator to take on about 12 ounces of distilled water and added enough extra into the overflow reservoir to reach the L level while the engine was cold.

I next went to the hot water valve under the hood. Thankfully its conveniently located at the top left center of the firewall, just left of the imprinted VIN number in the firewall. You'll notice several hoses around it and under it. These all flow coolant to the heater core and or are the return hose for the heater core. Basically the hose to the valve should be very warm once operating temperature is reached. If the valve is opened, the hose on the down side of the valve should be very warm, and thus the return hose from the firewall should be very warm as well.
Additionally, you will see a cable with an eyelet attached to the water valve. This opens and closes the valve as needed by the HVAC CPU.

In my case the cable was unattached. I reconnected it and the valve was now in the open flow range however all hoses were cold.. I then released the clamp on the hose going into the valve and attempted to release any air that may be in the system. I did not separate the two, merely manipulated the hose so air could escape while turning it on the fitting. After a few minutes of this I placed the clamp back on the hose and checked the inside of the vehicle.

Voila, I now have heat.

Additional note is this: I had the Timing belt, water pump, tensioners, pulleys, and cam seals replaced in September. Being that I live in Orlando, FL, I had no reason to use heat until yesterday. No doubt the mechanic left the hot water valve cable off when he did the work, as well as did not fully bleed the system. The Hot water valve is the highest point of water to flow in the entire car. Makes sense that air would escape to that area when you open the cooling system up.

Glad I did not have to ride to the dealer, pay a diagnostic and possible repair fee either. While the mechanic may have been at fault here, its tough to go back after four months and attempt to attach this to that maintenance repair.

Randy B

ancdmd

Thanks for posting your diagnostic and repair experience. Need more of these types of posts here on this forum, and a lot less of the annoying "is this 200x LS with XXXX miles a good deal?" posts...