Aircon

E30s are cool. But they won't keep you cool, and if you've got a tin-top in Diamond Metallic Black, then come those summer months you're really going to want something to lower the temperature in the cabin. That's where Aircon comes in.

Overview

Air-conditioning was fitted as an optional extra to all E30s as early as 1984, except the 333i where owners had to choose between aircon and power steering. The system remained largely the same throughout the E30 production run, and is based around a sealed refrigerant oil, just like your fridge at home. I won't explain the science, but as the refrigerant is converted from a gas to a liquid it gains heat; as it goes back to a gas it loses heat and cools, and it is this cooling effect we make use of. It's therefore essential that our system be completely sealed, to keep the refrigerant inside and doing what it should.

The system uses a number of components to compress, liquify, filter and evaporate the refrigerant. Valves regulate the flow of refrigerant through the pipework, and the whole system is controlled from a switch on the dashboard. A pressure switch monitors the condition of the coolant and determines whether or not the compressor needs to be engaged; if required, the clutch locks to drive the compressor.

Since its introduction, the original refrigerant has been made illegal for environmental reasons in the EU and many other states. A conversion kit to a more modern coolant is available from BMW.

Components

Compressor

Condenser

The condenser looks suspiciously like a radiator, and is mounted in front of the main vehicle radiator. Its job is to receive the hot and pumped refrigerant gas, and to condense it into a liquid. Its location means that it will receive airflow through the front grille, but it is assisted by an electric fan mounted in front.

Fan

Since the condenser mounts in front of the existing radiator, an electric fan is added to the condenser to aid air flow through the engine bay. The fan bolts directly to the condenser.

Expansion Valve

The expansion valve directly connects to the evaporator, and regulates the flow of refrigerant.

Evaporator

Heater matrix containing evaporator

The evaporator is a form of radiator, only in reverse. In the evaporator, the incoming liquid has space to expand into a gas, and as it does so it cools from the inside, creating the lovely chill that we expect from aircon.

The evaporator panel is housed inside the the heater matrix, which is an aircon-specific unit. For that reason, installing the evaporator means changing the entire heater matrix.

Pipework

The piework of the Aircon system delivers the refrigerant back and forth between the condenser and the evaporator, and everything in between. It follows a snaking path along the right side of the engine bay, entering the cabin area through a pre-stamped hole by the battery tray, and returning through holes drilled into the bulkhead.

The pipes are metal-cored with screw fittings to obtain the best possible seal for the refrigerant. Because of this, they are prone to corrosion over long periods of time, especially if the system is left discharged or if the receiver drier has not been replaced regularly. THey should only be replaced with new genuine BMW components.

Refrigerant

The system takes 975g (2.1lbs) of refrigerant.

The original refrigerant gas for the aircon system was R-12; one of the more aggressive CFCs. It was banned in 1994.

However, since the E30 was still being produced in some markets in 1994, the final volume of aircon-equiped vehicles received a conversion kit to the less malevolent R-134a. Since the refrigerant in all E30s will be due for replacement (known as "recharging" the system), it is essential to convert your aircon over to an R-134a compatible system.

R-134a Kit

The R-134a kit includes a new receiver drier, valves, pressure switch and some O-rings, like so:

Installation

Main article: Retrofitting Aircon.

Almost every car these days leaves the factory with air-conditioning, and this causes a shock to our soft, pampered bodies when we get into an E30. So to give yourself a (not-so) modern convenience, learn more about retrofitting Aircon.

Common Problems

Aircon systems use a controlled substance at their core. We do NOT recommend working on these systems yourself. In the event of any problems with your aircon system, consult a refrigeration specialist.

Aircon Won't Turn On

You press the switch, it lights up, but nothing happens. Most of the time, this is caused by a lack of refrigerant. If you haven't had the system serviced in a long time, it's not surprising for the cooling gas to have boiled or leaked away. If you don't replace the refrigerator drier then moisture in the system allows the pipes to corrode, leading to leaks. With all the refrigerant gone, there's nothing to provide any cooling effect, so you need to take the car to a professional.