Doug McAllister/Under the Hood: A/C system doesn’t take the winter off
Q. Why would I want to get my A/C repaired before heading into winter?
A. This question comes up quite often as we get toward the end of the summer cooling season and it came up again last week when we had a couple of those warm days. The client realized they were no longer getting cool air out of the vents so they brought the car in to see why.
After finding the vehicle was low on refrigerant, we isolated the leak at one of the hoses going to the A/C compressor. The client was of the mind to put the repair off till next year so as to not have to part with the money right now. We explained to them why that might not be such a good idea.
Anytime you have a leak in an A/C system, refrigerant is replaced by air, and air contains moisture. One of the biggest threats to an A/C system is moisture. By not repairing the hose you will expose the system to moisture for several months, rendering the Drier that is in the system fouled and in need of replacement at a minimum. Needless to say this will increase the cost of the repair.
The second big consideration for winter driving is the defogging and defrosting ability of the heating system. As you know your air conditioner removes moisture from the air and the ability to clear your windshield is greatly reduced if you don’t have a functioning A/C system. The next time your windshield is fogged up, try clearing it with your A/C off and then switch it on and you can see the difference for yourself; the windshield will clear almost instantly as soon as you turn on the A/C.
Q. I noticed on a cool morning the other day the heater in my car was not very warm. The temperature gauge is sitting where it normally sits right at about half gauge, the coolant is full and the hoses feel very warm to the touch. If everything is at proper operating temperature, why would I not be getting any heat?
A. If everything is as you say and your engine is running at the proper operating temperature, there could be a couple of possibilities causing this. The first thing I would want to check is all the blend door actuators, or cables depending on how your system operates. Sometimes everything is working properly and the heater core is actually getting hot, but the air is not being diverted over the heater core like it is supposed to. The other possibility is that the heater core itself is fouled or plugged up.
The heater core is like a tiny little radiator inside your dash that gets hot and transmits the heat from your engine to inside the car. Sometimes the heater core can become coated with debris and it just won’t transmit the heat properly.
In most cases you can connect directly to the heater core and flush it out, allowing the coolant to flow properly and once again the transfer of heat. In some cases a new heater core may be required. If the heater core is plugged, I would recommend flushing the whole cooling system, otherwise it may just happen again. If there is debris in the heater core then the engine most likely has debris in it, as well.
Ÿ Douglas Automotive is at 312 S. Hager Ave., Barrington, (847) 381-0454, and 7218B Virginia Road, Crystal Lake, (815) 356-0440. For information, visit douglasautomotive.com. Send questions to underthehood@dailyherald.com.