Because of Environmental Protection Agency policy, 1986 Nissan pick-ups need to use R134a Freon in their air conditioners. Once the Freon levels deplete, the pick-up will cease to produce refrigerated air. The system itself will not be broken, as the air conditioning will only need its Freon levels recharged. This is not a task to stress over. Adding R134a Freon is not a complex task. Recharging kits are widely sold at automotive parts retailers.
Pop your 1986 Nissan truck's hood. In the engine compartment, you will find a series of metal tubes. These aluminum pipes will contain a high side and low side connection point. Your R134a kit's servicing hose will not fit the high side connection point. It will, however, fit the low side connection point. Remove the low side's connector's cap and attach your kit's servicing hose.
Leave the kit in a safe place. It should not be next to anything that will jar or jostle it once the Nissan's engine is started. This includes both fans and belts.
Start the Nissan's engine and allow it to idle. Watch the vehicle's temperature rise on the instrument cluster's temperature gauge. Once the truck is warmed up, turn on the air conditioner to its coldest and strongest-blowing settings. This will help you take accurate air temperature readings inside the system.
Place a thermometer into one of the Nissan pick-up's air conditioner vents. Watch the thermometer's readings as the air conditioner's internal temperature drops. It may not drop that far, depending on how much R134a is left in the system. If the Freon levels are completely depleted, the temperature may not drop at all. Once the system's temperature becomes consistent, remove the thermometer.
Open both the driver and passenger-side doors before returning to the Nissan's engine. This will keep air from building up within the Nissan's passenger compartment. As a result, it will also keep the air conditioner from accidentally switching off.
Turn the nozzle on top of the R134a canister. The nozzle will open the can's seal, allowing the Freon to flow into the air conditioner's metal pipes.
Let the Freon flow for a minute and then close the nozzle. This will let you read the kit's pressure gauge, and more importantly, it will allow the Freon to completely travel through the system, stabilizing under the system's internal pressure. Add more Freon in increments, with at least a minute between each installment.
Place your thermometer into the Nissan truck's central air conditioning duct. As you add increments of Freon, watch the thermometer's readings. The system's internal temperature will begin to fall. A fully charged system runs at 40 degrees while running at full blast.
Shut the nozzle at the top of the R134a canister tightly once you have finished recharging. Remove the kit's servicing hose from the air conditioning's low side connector. Replace the low side connector's covering and shut the Nissan truck's hood.
Allow the engine and air conditioner run for another five to 10 minutes. This will ensure that the newly added Freon isn't concentrated into one part of the air conditioning system.
