Frequently Asked Questions About Mack R Truck AC Driers & Compressors

What years and models of Mack R trucks are these AC driers and compressors compatible with?

Our AC driers and compressors are designed to fit Mack R model trucks from 1966 through 2004, including the R600, R685, R686, R688, RD, and RW series. However, compatibility can vary based on your specific engine configuration and whether you have factory AC or aftermarket systems. We recommend checking your existing part numbers or contacting our support team with your VIN to ensure proper fitment.

How difficult is it to replace the AC drier and do I need special tools?

Replacing an AC drier typically takes 1-2 hours for someone with basic mechanical experience. You'll need standard hand tools, a manifold gauge set, and a vacuum pump. The system must be properly evacuated before removal and recharged after installation. Many customers choose professional installation to ensure proper refrigerant handling and system performance. Always replace the drier when replacing the compressor to prevent contamination.

What's the difference between OEM and aftermarket compressors, and which should I choose?

OEM compressors are built to original Mack specifications and typically carry a higher price point but offer guaranteed fitment and longevity. Aftermarket options from reputable manufacturers like Sanden and Red Dot can provide comparable performance at 30-40% less cost. Both options work well, but OEM units often have better warranty coverage and may last longer in heavy-duty applications. Consider your budget and how long you plan to keep the truck.

How often should I replace my AC drier, and what are signs it needs replacement?

AC driers should be replaced every 3-4 years or whenever the AC system is opened for major repairs. Signs of a failing drier include reduced cooling performance, moisture or oil spots near AC fittings, unusual compressor noises, or intermittent cooling. A saturated drier can't remove moisture from the system, leading to corrosion and compressor failure. It's cheap insurance to replace the drier during any compressor service.

Can I convert my R12 system to R134a when replacing these components?

Yes, converting from R12 to R134a is possible when replacing your compressor and drier, but requires additional components. You'll need R134a-compatible O-rings, the correct PAG oil, new service port fittings, and possibly a larger condenser for optimal cooling. The drier must be specifically rated for R134a use. While the conversion typically results in slightly less cooling capacity, it's often necessary since R12 is no longer readily available. Consider a complete retrofit kit for best results.