2019 GMC Sierra 1500 A/C Refrigerant & Oil Capacity Guide

As an ASE-certified HVAC technician, I know that servicing the air conditioning system on late-model trucks requires precision and the right specifications. The 2019 GMC Sierra 1500 represents the beginning of a new generation (the T1XX), which brought several updates to the HVAC system, including the complete transition to the newer, environmentally friendly R-1234yf refrigerant.

If you're looking to service, evacuate, or recharge the A/C system on your 2019 Sierra 1500, having the exact OEM specifications is critical to preventing compressor failure and ensuring maximum cabin cooling.

Disclaimer: Under EPA Section 609, any technician who maintains, services, repairs, or disposes of motor vehicle air conditioners (MVACs) must be properly trained and certified. Always wear safety glasses and gloves when handling refrigerants.

Quick Answer: 2019 GMC Sierra 1500 A/C Specs

• Refrigerant Type: R-1234yf (GM began transitioning from R-134a to R-1234yf around 2014, and by 2019, all Sierra 1500 models use R-1234yf).
• System Charge Capacity: 21.2 oz (600 grams) for standard systems. (Note: Always verify with the under-hood A/C specification decal, as exact capacities can vary slightly based on engine option and cab configuration).
• PAG Oil Type: R-1234yf specific PAG 46 (often designated as ND-Oil 12 or equivalent).
• PAG Oil Capacity: Approximately 4.0 to 5.0 oz (120 - 150 mL) total system capacity.
• Service Port Locations:
  • Low-Side Port: Located on the larger diameter suction line, typically near the passenger-side firewall or inner fender area.
  • High-Side Port: Located on the smaller diameter liquid line, closer to the front of the engine bay near the condenser.

Why R-1234yf Matters

If you are used to working on older trucks, the switch to R-1234yf is a big deal. The EPA mandated this transition because R-1234yf has a Global Warming Potential (GWP) of less than 1, compared to R-134a's GWP of 1,430.

However, this environmental benefit comes with a few headaches for the DIYer and independent shop:

• Cost: R-1234yf is significantly more expensive per ounce than R-134a.
• Equipment: You cannot use your old R-134a gauges or recovery machines. R-1234yf systems have different service port fittings to prevent cross-contamination. Shops must invest in expensive, specialized recovery/recharge machines that feature built-in refrigerant identifiers.
• Flammability: R-1234yf is classified as mildly flammable (A2L). While safe in the vehicle, it requires specific handling procedures during extraction and charging.

Recharge Procedure

When servicing the 2019 GMC Sierra 1500 A/C system, forget the old "top off" method using pressure gauges alone. R-1234yf systems are highly sensitive to charge levels; being off by just an ounce or two can cause the system to underperform or shut down entirely to protect the compressor.

1. Evacuation: The system must be completely evacuated using a dedicated R-1234yf recovery machine.
2. Vacuum: Pull a deep vacuum (at least 29.9 inHg) for a minimum of 30-45 minutes to boil off any moisture in the system.
3. Charge by Weight: The only accurate way to recharge this system is by weight, not pressure. Inject exactly 21.2 oz (or the amount specified on your under-hood decal) of liquid refrigerant using a calibrated digital scale or automated A/C machine.
4. Oil Injection: If components were replaced (like the condenser or compressor), you must measure and add back the exact amount of PAG 46 oil lost during recovery and component removal.

Common A/C Problems for this Vehicle

While the 2019 Sierra 1500 is a robust truck, the new-generation A/C systems do experience a few common hiccups:

• Condenser Leaks: The condenser is mounted at the very front of the grille and is highly susceptible to rock strikes and road debris. Micro-leaks here are the number one cause of low refrigerant in these trucks.
• Compressor Clutch Failures: Occasional premature wear on the compressor clutch or control valve can lead to intermittent cooling, especially at idle.
• Evaporator Core Leaks: Though less common on the 2019s than previous generations, a leak in the evaporator core (located deep behind the dash) will often present as a faint sweet/chemical smell in the cabin before the system stops blowing cold.

When to Call a Pro

Because R-1234yf is expensive and requires precise charging by weight, A/C service on a 2019 Sierra is no longer a driveway job with a cheap auto parts store can. If your truck is blowing warm air, the system is likely leaking. Simply attempting to force refrigerant into the low side without finding the leak will waste expensive refrigerant and potentially hydro-lock your compressor if you introduce too much oil or liquid.

If you suspect a leak, or if your A/C compressor is making grinding noises, it's time to hand the keys to an ASE-certified professional who has the expensive electronic leak detectors and R-1234yf recovery equipment required to do the job right.

Find a certified A/C shop on Repairius.