When not even a whiff of cool air is coming from your dashboard vents, it’s time to have your air conditioner serviced. But what about when it kind of works? An easy test is to check the temperature at the main, centre vents. An AC thermometer is the best tool as it reaches the recommended 7.6 centimetres into the vent, but in a pinch, I have used a meat thermometer netting a reasonably accurate result. Close your windows and take the vehicle for a quick drive with recirculate on and the AC on its highest setting, then park it and let it run for 10 minutes. Any normal operating system should record a temperature of between 4 and 9 degrees at the main vent. If your vehicle is in that range, chances are it is working correctly.
Lou Trottier uses an air conditioning thermometer to check the temperature of an AC system.Lou Trottier/The Globe and Mail
Contemporary vehicles use far less refrigerant than from those of 30 years ago. On a hot day, your dad’s Oldsmobile Delta 88 could reach meat-locker frigidity within minutes because that system used almost triple the amount of refrigerant. Half of the people who come in with a questionable system don’t have any real issue other than expecting it to work faster. Adding passengers can cause the system to struggle, especially when idling in traffic, which causes the AC compressor speed to be at its lowest.
Air conditioning, part 2: When refrigerant isn’t what it seems
The first generation of vehicles featuring auto stop/start features used a traditional air conditioning compressor that also shut off when the vehicle’s motor shut off at a traffic light. When cabin temperatures rose, the vehicle would sometimes restart to control the interior temperature. Many manufacturers are now switching to electric compressors like those found on electric cars to keep the AC operational even when the engine has shut off.
If your vehicle’s air conditioning works well for an extended period and then intermittently fails, this usually indicates an electrical problem. The compressor’s electromagnetic clutch or thermal protector is overheating and shutting down until the vehicle cools.
Cool air on one side of the dashboard and warm air on the other typically represents a vehicle that is low on refrigerant. The side closest to the evaporator will be coolest. There could also be a problem with the blend, air-mixture doors located in the dashboard that mix fresh outside air with cooled air as controlled by your climate-control system.
The most common query by far, however, is how to get rid of that musty, stinky smell from your air conditioner? The best way is to not let it happen. As mentioned in part one, regularly lift your hood and clean all debris from the cowl area. It is this debris that works its way down and causes mold and mildew. Once it is present it is tough to remove, but you can try spraying with vent and duct cleaners that are available at any parts store. Persistent smells that won’t go away with multiple applications will require professional help.
Your automotive questions answered
Hi Lou,
I’ve had my 2007 Subaru Outback serviced at the same repair shop since I bought it used four years ago. About six months ago, they did a full brake job (pads and rotors on all wheels) for about $1,000. I’ve driven about 8,500 kilometres since. Recently, a noise developed from one of the wheels and I took the car to a different shop where I bought my tires. The tire shop found that the caliper slider pins on all four brakes were seized. They told me that these should have been serviced when the brakes were repaired. It cost about $250 to fix this and service the brakes. Is it worth following up with my original mechanic or should I be looking for a new mechanic?
Thanks,
Tom M.
Why didn’t you return to the place that had just replaced the brakes? That being said, yes, the caliper slider pins should have been lubricated properly, however stuck slider pins did not cause the noise, I would imagine corrosion did. I can understand missing one seized slider as it happens sometimes, but to have a seized slider pin at all four corners six months after a professional brake job is rare.
As I’ve written before, our industry is well known for throwing each other under the bus mentality to win over new customers. I would definitely return to the original shop to have a word with them, but it sounds like there might be some exaggeration happening on the part of the second tire shop.
Hi Lou,
I have a 1992 dinosaur, a GMC 2500 Vandura with 5.7-litre engine. The van is mostly used for occasional camping trips and lumberyard errands. There is 210,000 kilometres on the engine. I was doing some errands and when I came out and started the van, the “check engine light “came on and the oil pressure gauge was reading zero. I shut off the engine and restarted it. The oil pressure came back to mid-range (normal) and the “check engine light” went out. I drove to the next location and this time when I restarted the engine, it stalled, and the oil-pressure gauge was fluctuating between zero and normal. I restarted it and oil pressure was reading normal. The van was running okay, but just acts up when starting. Any Ideas as to what may be causing this?
Thanks,
Doug G.
It sounds like the engine is possibly misfiring and not running on all eight cylinders when first started. When this happens, the revolutions per minute at idle will be below normal. This results in an oil pump that is barely pumping any oil. A misfiring engine is obvious on a four-cylinder, but may not be as pronounced with eight. The result is erratic oil pressure readings. Also, bear in mind that the gauge on your dash is not very accurate. Your van will likely also have a low-pressure oil light, which I would place more credo in, but I am going to assume that it has not come on since you have not mentioned it. I wouldn’t assume the oil pressure light is directly related. Look at the computer for what is causing the check engine light to be on.
Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail globedrive@globeandmail.com, placing “Lou’s Garage” in the subject line.
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