Frequently Asked Questions About Freightliner FLT Cabover Heat & AC Parts
Will these HVAC parts fit my specific year FLT model, and are there differences between FLT86 and FLT104 systems?
Most heat and AC components for Freightliner FLT cabovers are compatible across model years from 1980-1991, but there are important distinctions. The FLT86 and FLT104 models share many common parts like blower motors and evaporator cores, but mounting brackets and ductwork can differ due to cab size variations. Always verify your specific model number and OEM year before ordering. Critical components like compressor fittings changed from R-12 to R-134a systems around 1993-1994, so ensure you're ordering the correct refrigerant-compatible parts.
What are the most common failure points in FLT cabover HVAC systems, and which parts should I keep on hand?
Based on service records and customer feedback, the most frequent failures occur with blower motor resistors (typically lasting 3-5 years), heater control valves (prone to sticking after 100,000 miles), and evaporator drain tubes (which clog and cause cab floor water damage). We recommend keeping a spare blower motor resistor and replacement heater hoses in stock. The original plastic blend door actuators are also failure-prone - many operators upgrade to our reinforced aftermarket versions that feature metal gears instead of plastic.
Can I convert my R-12 AC system to R-134a, and what parts will I need?
Yes, R-12 to R-134a conversion is common and necessary for FLT cabovers. You'll need a conversion kit that includes new O-rings (R-134a compatible), proper PAG oil, new service port fittings, and a replacement receiver-drier. The original compressor can usually be retained if it's in good condition, but you must flush the system completely and replace all rubber hoses with barrier-type hoses rated for R-134a. Total parts cost typically runs $150-300 depending on component condition.
How difficult is it to replace the heater core, and can it be done without removing the dash?
Heater core replacement on FLT cabovers requires partial dash removal and typically takes 4-6 hours for experienced technicians. Unlike some trucks where you can access through the glove box, FLT models require removing the lower dash panel, disconnecting the heater box, and sliding it out from under the dash. You'll need basic hand tools plus a refrigerant recovery system if the AC evaporator shares the same housing. Many customers report success doing this job themselves with patience and our detailed instruction sheets included with replacement cores.
Are aftermarket HVAC parts reliable compared to original Freightliner components?
Quality aftermarket parts often match or exceed OEM specifications, particularly for wear items like blower motors and resistors. Our suppliers manufacture to original Freightliner specifications, with some improvements like upgraded bearing designs in blower motors and corrosion-resistant aluminum heater cores (versus the original copper/brass). The main difference is price - aftermarket components typically cost 40-60% less than remaining OEM stock. We recommend OEM for critical fit items like evaporator cases and ductwork, but aftermarket for replacement motors, cores, and electrical components.
