A/C service? In November?

by Gary Hansen

If there’s one thing you can do to get rolling faster on a cold morning, it’s to have your air conditioner inspected at the start of the heating season. Your truck’s defroster uses the air conditioner to pull excess moisture out of the cab. A properly functioning A/C system will help it clear the windshield faster and more efficiently.

While HVAC repairs demand special tools and training, routine inspections are within anyone’s grasp. That’s because your primary diagnostic tools are with you all the time: your hands.

Touch and feel are no replacement for a qualified A/C technician and his service tools. But they can give you clues about your system’s performance and help speed up the troubleshooting process. Here are five things you can do any time of year to reduce the risk of a costly A/C repair:

Air flow
Turn on your blower motor and hold up your hand to a vent. Is the air flow as strong and steady as always? The first sign of a plugged fresh air intake filter is a feeling that not enough air is coming into the cab. When the filter has collected so much dirt, dust, hair, and other particles that the air can’t pass through freely, it’s time to replace it.

There are several types of filters available:

Paper: The most common type of fresh-air intake filter is made of pleated paper, like the air filter on your engine. Dirt and debris settle into the folds and build up from there.

HEPA: HEPA (High-Efficiency Particulate Air) filters are made of high-density pleated paper and capture extremely small particles that might be harmful to people with allergies or asthma.

Foam: Some filters are made of open-cell foam that’s charcoal-impregnated to help trap particles from cigarette smoke and neutralize odor.

Your owner’s manual will tell you which is best for you and provide a recommended inspection interval. That probably means checking the filter at least twice a year and using a replacement that meets the original-equipment spec’.

Refrigerant flow
The receiver-drier on an air conditioner contains desiccant to remove moisture from the refrigerant. When moisture and refrigerant combine, the result is corrosive hydrofluoric acid, so it’s important to make sure the receiver-drier is functioning properly.

With the system on, the receiver-drier should be warm to the touch. If the canister feels cold, or you see frost on it, there’s probably an internal restriction and it needs to be replaced.

Some receiver-driers have a moisture indicator that provides a quick visual cue about the refrigerant’s condition. A blue dot means the refrigerant is dry; pink, white, or gray indicates moisture in the system. Check the sight glass any time your truck is in for an oil change or other routine service.

The receiver-drier should be replaced every time the A/C system is opened or once a year (mark the installed date on the new drier so it’s easy to see). Use a quality all-makes replacement – some cheaper driers lack sufficient desiccant.

Spongy heater hoses
Heater hoses degrade from the inside out, the result of an electrochemical reaction between the coolant (anti-freeze) and different metals in the cooling system (steel clamps, copper heater core, cast-iron head, etc.) Tiny cracks develop in the tubing, typically near the hose ends, which can allow the coolant to reach and degrade the reinforcement yam.

As the hose deteriorates, it sheds debris into the anti-freeze. Now not only is there a weak point in the hose, you have foreign material circulating through the heater core.

With the system off, squeeze the heater hose near the ends, between your thumb and fingers, to gauge its firmness. A spongy hose is a sign that it’s weak and should be replaced.

Sticky heater water valve
It was a hot summer in Canada. You probably didn’t run the heater much. Your truck’s heater water valve can stick after a season of disuse and affect your ability to control the temperature in the cab.

If you have a cable-actuated valve and feel resistance at the slider control on the dash, don’t force it. You risk bending or damaging the cable. Instead, try actuating the valve manually to break it free.

Cycling it several times by hand usually does the trick.

You may need to momentarily disconnect the cable to manually actuate the valve. If it’s necessary to remove the cable, mark the cable position first before you remove it.

For electric water valves, turn the dash control to full “hot” and note the valve position. Next, turn the dash control to the fully “cold” position and recheck the valve position. It should be different. If not, have the valve checked by a qualified technician.

Oily grime on the compressor

The compressor is the single most expensive replacement component on the A/C system. If it leaks oil, it can overheat and lead to a catastrophic failure.

With the system off, feel for oil or dirt around the shaft seal and for glazing or cracking on the belts. At the same time, look for discolouration on the face of the clutch hub. Any one of these is a sign of heat or potential failure and should be checked by a qualified A/C technician.

The key to feeling comfortable in your cab is to feel comfortable with the components on your A/C system. You don’t need special tools or knowledge to perform inspections. You just have to get your hands a little dirty and be diligent about incorporating the A/C system into your PM routine.

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