Esprit Models
Esprit History
For Sale
Other Stuff
Buying & Running
Parts & Specialists
Other Esprit Stuff

Air Conditioning Charging
Topping up your AC DIY Style or getting it done for you

A/C - Early cars used Refrigerant called R12.(now obsolete). This was changed to R134a which is used worldwide today. Old Cars that have R12 therotecially can not use R134a although it can be used but will not work properly and be inefficient. The aftermarket has developed a product (known as RS 24) to replace R12 which is compatible with the components on these vehicles. Most A/C specialists can provide this service.

From Lotus Cars
The change in the A/C gas from R12 (CFC12) to R134a (HFC134a) was introduced in March 1995. A Service Bulletin 1995/06 was released to the Dealer Network in Feb. 1995. The introduction points were as follows:-

Esprit (RHD)
S4 S 2031
S4s S 4035 (S 4002 Australia)
Sport 300 S 8058
Esprit (LHD)
S4 S 2017
S4s (USA) S 3012
S4s (non USA) S4006

The Label on the Compressor will identify which system is fitted to the car. R12 Gold Label SD-508 SANDEN, R134a Green Label SD7H15 SANDEN

The whole of the A/C system, with the exception of the evaporator (in car unit) and expansion valve, has changed. Refer to Lotus Service Notes for procedures and precautions when working on the Esprit A/C system.

Air Conditioning Charging
Getting it done for you at Reader Air Conditioning in Woking
by Cliff Ledger (87 Turbo Esprit)

I had not been happy with the air conditioning in the car for some time so I decided to get things soughed out. I took a deep breath and my cheque book to Reader Air Conditioning, Woking to get things fixed. Hopefully.

They where very busy and I had to book up 3 weeks in advance.

To start with Andy of Readers checked the vacuum pressure in the system. It appears that on the Lotus system there are two connections on the compressor. One for filling the system and the other containing the pressure safety switch.

A connection was made to the filler and the vacuum pump switched on to remove any remaining oil / refrigerant in the system. At the same time a vacuum is built up within the system which checks for any leaks and later allows the new oil /refrigerant to be drawn in.


The vacuum process normally takes between 5 and 10 minutes to complete its initial check. After 30 minutes the pump still had not finished…..

This meant only one thing. There was a leak….

The next step was to pump pressure into the system to try to discover the leak. No sooner had this been done a loud hissing could be heard from around the compressor. Upon inspection it was noted that the pressure switch was leaking.


The offending switch was removed and Andy popped off to the stores in search of a replacement. The switch is connected to the compressor by a brass connector which is removed and reused on the new switch.

On return a new switch had been found, but there was a concern over compatibility. The new switch showing the same minimum pressure as the old.

After a call to home to get Caroline, my wife, to check Bibs profile on the forum for Lotus Technical help line number, which is now please note in my mobile memory as clearly you never know when you may need it, I spoke to Lotus who where able to check the manuals for compatibly. It turns out the pressure switch is not a separately listed item, so Lotus advised it was fine to install, as the pressures where the same.


The new switch was installed and the system was once again tested for vacuum. This time reaching full vacuum within 5 / 10 minutes. The pump was left going for longer to make sure the system was totally purged then the new refrigerant was put in. As my car has the old R12 system a replacement drop-in gas RS24 was used.


The system was then tested and found to work correctly.

In fact for the first since I have owned the car I actually felt to cold and had to turn the air con down.

Big thanks to Andy at Reader Air conditioning, Lotus Technical Help Line and of course Bibs for pointing me in the right direction.

This guide was supplied by ClubLEW member Cliff Ledger on his 1987 Turbo Esprit HC

Evacuate & Recharge with RS24 = £99.87
Supply and fit pressure switch = £38.19

Total (inc VAT) = £138.06

Air Conditioning Charging
Topping up your AC DIY Style
by Nick S (95 S4s)

This job isn't difficult, but will depend on how long it take you to remove the undertray.

You will need the following parts:

EZ Chill Kit

You will need the following tools:

Assortment of tools to remove undertray

Recently my S4s air conditioning system was working less than marginal, so instead of calling someone out or taking to a garage to relieve me of £70 odd quid to charge the system back up i decided to use one of the Halfords DIY kits (Mine was the EZ Chill), for about £36 you get a can of R134a, a trigger assembly which screws on to the top of the can and has a built in gauge so you can see what state your system is in.

Of course to achieve the 'perfect' Lotus air conditioning system you have to first gain access to the charging points (this is the clever bit), the charging points are located underneath the car, but wait it gets better, you have to remove the under tray first.which is 'simply' held on by around 12 bolts that will probaly be rusted and the bobbin (insert) will rotate ! Once the tray is removed you will find the charging points on the drivers side(R/H) towards the front of engine bay, just look for the compressor and follow the lines from it you will find them covered in oil/grease.There are two connection points but you will only need the 'low side' which is easy to find as its the smaller one and the connection on the EZ Chill kit will only fit the correct side.The pic shows the general area where the points are hidden, you also may find that they are more to the centre of some cars.

Once you have correctly identified the charging point and removed dust cap, start the car put the a/c on and connect up the EZ Chill adapter and read off the gauge what your system has in it and check your readings off against the chart. If you need to top up then simply screw can of R134a onto trigger assembly and squeeze trigger to release refrigerant into system stopping regularly to check refrigerant level. Now your Esprit should be nice and cool, if it isn't then you probaly have a leak or the compressor is not very well, some of these DIY a/c kits say that they can 'cure' leaks, which would be great if not slightly dubious, you never know it may actually work!

Once you have finished self congratulating, just remove coupling and screw dust cap back on and 'simply' reattach the undertray.


I thought the kit was really easy to use and the instructions are totally 'idiot proof', i am not absolutely sure but i cant see any reason why it cannot be used on any Esprit with airconditioning most a/c points are of a standard size, so in conclusion simple and easy to use plus it does save you a few bob over taking it to a garage.

This maintenance was performed by Nick Fry on his 1995 S4s

If you have any comments, feel free to e-mail us at admin@lotusespritworld.com

May 2013
I read this very useful article and was pleased to find that a supplier is referred to.

However, I just rang them and they said that RS24 drop in replacement gas is no longer available so I'm wondering if it might be useful to update the page, either with a new supplier (if the gas even exists anymore) or to mention that Reader can no longer provide the service.

Hope this is helpful.



return to top
home email news esprit models road tests buying an esprit running an esprit esprit owners maintenance pictures for sale history Lotus models links