Off-Highway Truck Drivers: Are You Fighting Condensation & Frost On The Windshield?

Posted on: 29 August 2016

If you fight a battle of condensation and/or frost inside the cabin of your employer's off-highway truck, you are probably concerned about the safety aspect of not being able to see. Here's what you'll need to check and what you can do to get rid of the condensation and frost so you can see through the windshield clearly from the beginning of your shift to the end.

How Condensation and Frost Forms

Condensation is tiny droplets of water. Condensation forms when water vapor (humidity) in the air combines to form tiny water droplets. This combination of droplets is caused by temperature differences. The droplets are spaced apart when the air is warm and move closer together when the air cools or the water vapor reaches a cooler surface. The temperature when this happens is called the dew point. Frost is frozen condensation.

Where the Moisture Can Come From

With this basic understanding of how condensation forms, you can see that your main problem is that there is too much moisture inside the cabin of your off-highway truck. But, where is the moisture coming from?

  • Is the cabin air filter clogged? A clogged cabin air filter can trap moisture in the vent and inside the truck. This can also make the truck smell musty when you run the air conditioning. Read the owner's manual to learn how to change the cabin air filter in the specific make and model of the off-highway truck.
  • Is the air intake in the cabin set to recirculate? If it is, set it to fresh air instead. This will help remove the moisture from inside the cabin while you operate the heater, defroster or air conditioner. If it's necessary to have the air intake set to fresh air, it's a good idea to keep an absorbent material inside the cabin, such as a few pieces of chalk or a pack of silica desiccant designed for RVs and trucks. That way, this moisture that comes in through the air intake vents can be absorbed.
  • Is moisture coming in through cracks in the seals around the windshield and/or windows? Over time, the seals around the windshield and windows can crack, which can cause moisture to get into the cabin. Check the rubber seals closely for obvious signs of damage. Replace the seals if any cracks or holes are found.
  • Does the heater core have a leak? A leak from the heater core will have a sweet smell that is similar to syrup. The condensation may have a residue, especially if the leak is major. It's actually the coolant from the engine that you would smell if there's a leak in the heater core, which can become serious and cause the engine to overheat if too much coolant is lost. If you smell coolant or a sweet odor, the off-highway truck will need to be loaded up and hauled to a heavy equipment repair shop.
  • Is there a blockage in the condenser drain of the air conditioner? A blocked condenser drain can make the cabin smell musty or moldy. You may be familiar with this odor as it's the same as the first time you run your car's air conditioner at the start of warmer weather. The system may simply need a burst of air through the drain line to get things moving if there is a blockage. However, it's a good idea to have the system checked for interior mold growth, which means the truck will need a trip to a repair shop for a thorough cleaning.

If you cannot figure out where the moisture is coming from, a heavy equipment repair mechanic will need to be hired to troubleshoot the problem.