Truck Air Systems and Cold Weather

The winter brings with it changing weather. Not only does winter weather create hazardous driving conditions, but the material used to eliminate snow and ice cause corrosion for semi trucks and other vehicles. It is always a good idea to regularly check your vehicle for any issues you might encounter out on the road, but colder conditions leads to more frequent malfunctions, especially in the winter months. With drivers going into these colder months, here is our tips for Winterizing your air system. Understanding why to winterize your air system is a basic understanding of seasonal preventative maintenance. Along with corrosion, other concerns are heightened with the increased moisture in the air. The more moisture that your air compressor draws in, the more condensation will reside within your air tanks. Condensation can make its way to affecting your braking system and other related areas. Sometimes the weather wins out and air lines and other areas will freeze, leading to bigger issues.

Air Compressor

First check your wet tank for contaminants and moisture. It is normal for compressors to pass a little oil, but if you see sludge buildup, the oil is getting through the air dryer into the downstream air system. Tectran recommends checking at least every 3 months.

Also, "check your compressor discharge line for restrictions including carbon at the compressor outlet". Carbon is a good indicator of excessive oil passage, so if there is build up, replace the line. Look to see that the compressor discharge line is a constant downward slope to the air dryer (find more information here). Lastly, change the air governor. This is essentially the power switch for the air dryer purge function.

Air Dryer

Desiccant cartridges are used to keep products dry and stable, and are used when products are sensitive to moisture and humid environmental changes. Their life can be from 3 months to 3 years based on compressor oil passage and duty cycle. It is recommended that you replace it every fall, but most fleets replace them yearly. If your truck has high air usage, fall is also a good time to replace the purge valve due to it being susceptible to malfunctions from the contaminants it passes.

Check the air dryer heater for three things:

1. Proper voltage to the heater
2. That it's properly grounded (most likely the frame rail)
3. That it is functioning properly

Remember "if your vehicle uses an alcohol injector/evaporator, fill it up with approved air brake anti-freeze". Note: never add air brake anti-freeze directly into air lines.

Air Tanks

Look over all manual or automatic drain valves, and when in doubt just replace them. They are easy to access and also inexpensive. If you have automatic drain valves, inspect those as they are more likely to malfunction. Many fleets also replace these every fall. The last thing to look over is the full air system and check for air leakage.

Tractor/Trailer Connections

The air coils on a tractor/trailer act like springs that stretch and contract when the tractor and trailer separate, and the coil design reduces the risks of damage. However, they still are needing to be inspected for any abrasions, kinking or other damage, taking special care to check the end connections. Replace any that appear damaged. For the coming colder months, consider getting extra protected air coils to extend their life and also reduce the risk of damage.

Don't forget to look for wear or damage to the connection suspension devices (tender kits, clamps, hanger brackets, hose springs, pogo sticks). Replace these as needed. In colder areas, check your electrical cable and consider replacing it with ones built to withstand colder temperatures.

Replace all gladhand seals and filter screens (tip: polyurethane seals last longer). If you don't already have filters, upgrade to gladhand seals that have built-in filters to eliminate more possible contaminants. And finally, inspect your gladhands for corrosion. Replace all that appear corroded, and think about getting more corrosion-resistant ones for colder weather.