how to drain def tank on peterbilt

Written by Rick Sanderson in General Info

How to Drain DEF Tank on Peterbilt: A Step-by-Step Guide

The Diesel Exhaust Fluid (DEF) tank plays a vital role in maintaining your Peterbilt truck’s selective catalytic reduction (SCR) system, which helps reduce emissions and adhere to environmental standards. Sometimes, it becomes necessary to drain the DEF tank, perhaps due to contamination or for routine maintenance. In this comprehensive guide, we’ll walk you through the steps to safely and efficiently drain your DEF tank, ensuring you’re back on the road in no time.

Understand the Importance of Careful Handling

Before proceeding with draining your DEF tank, it’s crucial to understand the importance of handling DEF with care. DEF is a solution of urea and deionized water, and while it’s not toxic, it’s corrosive and can crystallize upon exposure to air, potentially causing damage to your truck or environment if not handled properly.

Tools and Equipment Needed

Ensure you have the following items on hand:

  • Protective gloves and eyewear
  • DEF-approved transfer pump
  • Clean container for capturing the DEF
  • Funnel (preferably with a filter)

Keep in mind that utilizing the correct tools is essential for a successful and safe process.

Steps to Drain the DEF Tank on Peterbilt

1. Locate the DEF Tank

Your Peterbilt DEF tank is usually located on the passenger side of the vehicle near the back of the cab or underneath the sleeper berth. Look for a blue cap, which is standard for DEF tanks.

2. Prepare Your Work Area

Choose a well-ventilated area for the draining process. Spread out plastic sheets or drip pans underneath the tank to capture any spills. Always wear your protective gear to shield yourself from splashes.

3. Access the Tank

Remove the blue cap from the DEF tank. Depending on your specific Peterbilt model, you might require a special tool to unscrew the cap. Refer to your owner’s manual if you’re unsure.

4. Begin the Draining Process

Insert the intake hose of your DEF-approved transfer pump into the tank. Direct the outlet hose into your clean container. Ensure the container is large enough to hold all the fluid in the tank to avoid overflow.

5. Pump Out the DEF

Turn on the pump and begin transferring the DEF from the tank to the container. Keep an eye on the process to make sure there are no leaks or spills.

6. Dispose of DEF Appropriately

Once drained, it’s essential to dispose of the old DEF properly. Check with local regulations or visit Environmental Protection Agency (EPA) for guidelines on disposal. Do not pour DEF down drains or onto the ground.

7. Refill the Tank if Necessary

After draining, if you intend to refill the DEF tank, ensure that the tank and system are clean to prevent contamination. Use a new DEF that meets the ISO 22241 standard. DEF has a shelf life, so always check expiration dates and the crystallization of the fluid before using. For more information on selecting the right DEF, refer to The American Petroleum Institute (API).

8. Replace the Cap and Finish Up

After you have completed the draining (and possibly refilling) process, seal the DEF tank by securely replacing the cap. Dispose of your gloves and clean your tools with water.

Additional Tips

  • Avoid using tools made of metals such as aluminum, copper, or zinc for handling DEF, as these can cause contamination.
  • Use a funnel with a filter when refilling to avoid introducing debris into the DEF.
  • Regularly inspect your DEF quality and tank for signs of contamination.

Understanding the DEF System in Peterbilt Trucks

Your Peterbilt truck’s SCR system, which includes the DEF tank, is critical for complying with the U.S. Environmental Protection Agency’s (EPA) stringent emission standards. The system injects DEF into the exhaust stream, where it breaks down nitrogen oxides (NOx) into harmless nitrogen and water vapor, significantly reducing emissions. It’s therefore essential to maintain a well-functioning SCR system to avoid engine performance issues and potential legal consequences.

Common Questions Answered

Q: How often should I drain my DEF tank?

A: Draining the DEF tank is not a regular maintenance task. It should only be done if there is evidence of contamination or as advised by a maintenance professional.

Q: Can I drain the DEF tank by removing a drain plug?

A: Most modern DEF tanks do not have a simple drain plug due to the risk of contamination. Always use a DEF-approved pump for the draining process.

Q: Is it safe to drive with an empty DEF tank?

A: No, driving with an empty DEF tank can trigger warning lights, induce engine derate, and even prevent your truck from starting due to compliance systems.

Conclusion

Draining the DEF tank on your Peterbilt truck might be an infrequent task, yet it requires careful attention to detail and an understanding of the process. By following these steps and adopting best practices for handling DEF, you will help ensure the longevity and performance of your vehicle’s emission control system.

Remember that while we strive to provide accurate and helpful information, it’s always best to consult a professional mechanic or your Peterbilt dealer for service-related tasks, especially if you feel unsure about the process.

For more expert insights and tips on truck maintenance and the trucking industry, keep following our blog. We’re dedicated to providing you with the best information to keep your rig running smoothly.

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