VW Golf Mk2 Owners Club

Monkeys guide to AC in your Mk2.

July 16, 2025, 02:03:28 PM

When installing AC into a mk2, there are many ways you can do it.
I’m going to write down how I did it, no idea if it’s the best way, but it’s working for me and as always, I take no responsibility for anything, ever.

Unless you have a 3.2/24v, you’re almost certainly not going to be copying this exactly.
But as number of people have asked me to write down how I installed AC into my mk2, here goes…


Basics:
Air conditioning relies on the expansion of refrigerant gas.
When it does this, it loses energy rapidly and immediately tries to recover it from the atmosphere around it, making everything cold.
These gasses are very toxic, hence having to be controlled by specialist garages and I’m just going to call it gas from here on in.

The system comprises of 4 main stages:

Compressor
This is the alternator looking thing that bolts to your engine.
It compresses the gas for expansion later. This process heats up the gas. It's controlled by an electromagnetic clutch that engages when you need ac and free spins when you don't to reduce load on the engine.

Condenser
This is the radiator that is mounted in front of your coolant radiator.
This chills the compressed gas down as much as possible before it hits the expansion valve.
The more it can chill here, the colder your air will be in the car.

Expansion Valve
This allows the compressed gas to expand, lose it’s energy and cool down.
It’s usually mounted on the bulkhead, directly to the Evaporator.

Evaporator
The matrix in the car that the air passes through to and is chilled through the now expanded gas.
It’s located inside the fan housing, inside the car.

Ancillaries
Other bits on the system:
Drier – captures any moisture created through condensation.
Pressure switch – this protects the compressor from running empty and possibly failing in the event of a loss of gas.
Schrader valves – to fill/empty the system
Pipework – this has to put up with pressures between 32-155 psi
Wiring – while basic, you need to be able to control the system.

So now that’s out the way, I’ll move on to what I used:

Compressor:
As I have an Audi TT 3.2 engine, I fitted the standard compressor to it.
It’s worth pointing out that everyone who fit’s a 3.2 in a mk2 removes the compressor as it fouls the front crossmember.
I had to cut mine down and substantially weld it back up to restore the strength.
Had the welding done by a professional to ensure it was done right!
Untitled by Dave Ackerman, on Flickr

Condenser:
I was running out of room at the front of the car and had already cut into my slam panel to allow the Corrado VR coolant radiator.
That being said, I found that a Lupo condenser is not only half the width of a normal one but also bolts directly up to a VR6 radiator.
Had to cut the top bracket a little to allow for the bonnet latch to sit home properly.
Untitled by Dave Ackerman, on Flickr

Expansion valve:
Dead easy, use a mk3 item to match the evaporator below…

Evaporator/fan housing:
So, this is the biggest and by far the trickiest part of the build…
I used a mk3 item and since buying it, I’ve heard that a mk4 item fits better.

Mk2 vs mk3 unit
Untitled by Dave Ackerman, on Flickr
No idea if this is a fact and how it looks when it’s in, but I had what I had and pressed on.
I didn’t even consider trying to source a mk2 setup, saw one a few years ago hit nearly a grand and it was all worn out!
Seems obvious, but don’t get a LHD fan housing for this, it will not fit (unless you have a LHD car).
I wanted to retain the standard flap controls and keep everything looking as OE as possible.
What I found was by chopping off a small bracket, I was able to mount the mk2 matrix housing to the mk3 fan housing using all the stock clips.
Untitled by Dave Ackerman, on Flickr
Whatever matrix housing you’re using, it’ll be very old by now, so take advantage of it being apart and swap the matrix and refurbish the heater flaps.
Untitled by Dave Ackerman, on Flickr

Now here’s the hard part, fitting the new assembly.
You need to take a brave pill and cut a not tiny hole in your bulkhead to allow the mount for the expansion valve to sit properly and for the fan inlet to line up with the stock hole in your scuttle panel. There’s no super easy way to do this, you have to mount up the two heater matrix screws on the bulkhead for reference and then mark up and go for it.
Untitled by Dave Ackerman, on Flickr

I started small and gradually got bigger and bigger with the hole until everything lined up.
Shot of the mk3 fan inlet matching the hole in the mk2 scuttle.
Untitled by Dave Ackerman, on Flickr
I then had to make a small enclosure to tie everything back together.
Untitled by Dave Ackerman, on Flickr
Untitled by Dave Ackerman, on Flickr


Is it pretty? No.
Is it watertight? Yes
Is it buried down the back of the engine bay and no one will really see unless they’re looking for it? Also yes.

Now the part that really adds time to this project is what you have to do to achieve the above.
I completely removed my engine (not strictly necessary but made the job much easier) and stripped the dash right back to the metal bulkhead.
I also pulled the carpet back as far as I could and covered the interior in a damp sheet when I was cutting/welding.
Still managed two small fires.
Between the strip down, the constant removing the installing of the box, the slowly cutting the hole out and fabricating the enclosure, this probably took me 5 or 6 weekends.
Didn’t help I also got distracted, fitted a timing chain, overhauled the cooling system and painted the block, put new sound deadening in… be warned – project creep happens!
Untitled by Dave Ackerman, on Flickr
Untitled by Dave Ackerman, on Flickr

Ancillaries:
Ok, now all of that was done, I refitted the engine and started planning the pipework.
Untitled by Dave Ackerman, on Flickr

This is the part that will vary the most for you, depending on what engine you’re running.
I managed to buy a full Lupo pipework setup from eBay, this made life so much easier.
Most ac pipework (mk3/mk4 and on) comprises of solid pipework and a small flexible pipes near the connections.
Lupo stuff is mostly flexible, making it much better when sorting out the routing.
In fact, I was able to use all the Lupo pipe work (including air dryer) and a single mk4 high pressure to expansion valve pipe.
Doing it this way, I was able to only have one non OE join in the whole system.
I did this on a 10mm straight section, next to the brake servo.
As both pipes were 10mm and solid, I used a stainless compression fitting to join them.
This particular one is rated to 90 bar (around 1300 psi!) so it was more than enough to deal with the pressure.
I also used brand new green o rings for every connection, you can buy boxes of them for about a tenner.
Mk4 section
Untitled by Dave Ackerman, on Flickr

Below is the join at the end of the mk4 pipe, turned out to be a great fit, you can even see it dodge the brake servo.
Untitled by Dave Ackerman, on Flickr


Wiring:
Once that was all in, all it needed was to be wired up.
Untitled by Dave Ackerman, on Flickr
This was something I actually started before the dash and engine refit, it just makes life much easier.
I used a US spec AC switch as it’s OE and matches the other switches on the dash.
I also bought a small IP rated relay box off of Amazon that had 6 fused relays.
I may yet move it, but as I had some real estate on the drivers chassis leg, that’s where it went.
The first two I (again got distracted) used for the high/low beams for my headlight upgrade.
Essentially, my plan for wiring is I take a switched live feed, go via the dash switch, then the pressure switch and use it to trigger the compressor clutch and relay 1.
Relay 1 then runs the radiator fan.
I also have a permanent live that goes through the radiator fan switch and triggers relay 2.
Relay 2 also runs the fan switch.
That way I can have two independent sources to run the radiator fan and don’t have to worry about anything back feeding anything else.
If anyone wants, I can look to draw up a wiring diagram to give you an idea.


Testing:
So once it was all in, I tested it with the engine off and a danger wire (think short piece of wire with 12v at one end and whatever I want to test at the other), making sure everything reacted as expected.
When I was happy, I used an AC refill kit to put some charge in the system, while this was happening, I sprayed some soapy water around all joints to look for any leaks.
Note – not all recharge kits come with lubricant, running it without can damage the compressor.
I then ran the system up and while it wasn’t great, it worked and blew slightly colder air out the vents.
Reason for doing this was so I could make sure the system worked without leaking before spending money on a professional to vacuum test it and then put gas in.
When they test the system, it has to hold a vacuum for at least 15 minutes, happy to say it passed without a hitch.
Afterwards, (using the Lupo as the car to select the capacity) 575g was installed in the system and it finally worked properly!

Afterthoughts:
Now while this was specifically for my car using my engine, it should be quite possible to use this as a guide, but when you do the compressor, buy a second hand mk3 setup. Twice in the past, I've managed to bolt up a mk3 accessory bracket to a mk2 block and get the multi v belt, this contains the alternator/PAS pump/water pump and if you get the right one, an AC compressor. Just make sure to get the loom (or a cut of it) to capture the correct connectors and splice them into your wiring. It's also worth noting you should get the correct donor for your car - 8v for an 8v and 16v for a 16v. Also, with all VW compressors being in roughly the same place, the lupo/mk4 pipework trick should work too.

Re: Monkeys guide to AC in your Mk2.

Reply #1 – July 17, 2025, 07:42:18 AM

Now one other thing to consider is how much it's going to cost.
I've tried to do everything myself, but here's a breakdown of what it's cost me to get installed:
Full mk3 AC setup (only really need the evaporator box, but I didn't know that then) £120
Mk2 Switch - £65
Crossmember Welding - £60
Full Lupo AC pipework - £110
Compression fitting - £7
Lupo AC Drier - £20
Lupo Condenser - £65
TT Compressor - £180
Mk3 Expansion Valve - £22
AC Regas Can - £30
Processional Regas - £46
Fusebox - £35
Consumables (welding/grinding/wiring/o-rings etc) - £40-£50
Pollen Filter Housing (3D Printed) £10/£15
Pollen Filter £15

So at just under £700, it's not a cheap undertaking, but if you to it like me over the course of a number of years, it's not too bad.

Re: Monkeys guide to AC in your Mk2.

Reply #2 – August 15, 2026, 01:39:39 PM

Hi mate, this is a great writeup.  My son and I are restoring a 1989 golf syncro rhd.  We want to put a/c in it.  We plan to use an electric compressor and fit that somewhere on the car that makes sense.  Thus, we don't need the compressor that normally fits on the engine.  As far as the dash parts are concerned for RHD, does this chat-gpt response seem pretty accurate?  I gave it all the etka diagrams for my car's VIN and asked it to produce an oem list.  I know these rhd mk2 a/c parts are more  "uncommon"  because I think maybe only South Africa market got them, maybe??

Anyway, you seem to have a good handle on this from at least the perspective of getting your hands dirty and doing the job, even though yours is a different car slightly and also you took donor parts from other models/years - which is really cool. 

I was just wondering if you could give some input on this list whether it's accurate and any other thoughts you have.

# VW Golf Mk2 RHD OEM A/C Conversion Shopping List

**Vehicle:** 1989 Volkswagen Golf Syncro RHD
**VIN:** WVWZZZ1GZKW493527
**Original engine:** GU — 1.8 EA827
**Factory A/C:** No

## 1. Highest-priority RHD A/C parts

These are the parts I would actively search for first because they are either specifically RHD or difficult to substitute with LHD pieces.

* [ ] **358 820 103 — RHD evaporator with expansion valve**

  * ETKA position 19.
  * This is explicitly the RHD evaporator.
  * LHD equivalent is `357 820 103`.
  * **Very high priority.**

* [ ] **358 820 021 — RHD A/C fan/blower assembly**

  * ETKA position 5.
  * Explicitly marked RHD.
  * LHD equivalent is `357 820 021`.
  * Do not confuse this with the ordinary non-A/C RHD heater fan `192 959 101`.

* [ ] **192 819 081 — RHD intermediate piece**

  * ETKA position 12.
  * Connects the HVAC assembly into the RHD air-distribution system.
  * LHD equivalent is `191 819 081 A`.

* [ ] **192 819 151 A — RHD footwell vent**

  * ETKA position 24.
  * RHD-specific outlet from the HVAC/distribution assembly.

* [ ] **192 820 353 — RHD connection box**

  * ETKA position 29.
  * ETKA calls for **quantity 2** on the RHD A/C installation.
  * LHD uses `191 820 353`, quantity 1.
  * This quantity/layout difference makes this one especially worth obtaining with a complete donor box.

* [ ] **192 820 593 — RHD cover**

  * ETKA position 34A.
  * RHD counterpart to `191 820 593`.

* [ ] **192 819 837 — RHD temperature-control flap cable**

  * ETKA position 36 on the A/C diagram.
  * Do not substitute the LHD `191 819 837`.

* [ ] **192 820 154 A — RHD intake duct**

  * ETKA position 38.
  * One of the important large plastic pieces between the body intake and HVAC assembly.
  * LHD equivalent is `191 820 154 A`.

## 2. Main RHD A/C heater/evaporator box

* [ ] **Complete RHD Mk2 A/C HVAC housing/box — verify actual molded part number before purchase**

  * This is what I would search for rather than attempting to assemble the housing from scattered plastic pieces.
  * Ideally buy it complete with:

    * evaporator;
    * blower;
    * flap assemblies;
    * vacuum actuators;
    * drain;
    * expansion valve;
    * thermostat;
    * brackets;
    * seals;
    * RHD connection pieces.

### Important ETKA anomaly

The VIN-filtered A/C page supplied here lists:

`191 820 024 A — housing — LHD`

but does **not** show a corresponding RHD housing number.

Therefore:

* [ ] **Do not purchase `191 820 024 A` assuming it will fit RHD.**
* [ ] Ask sellers for photographs of the actual RHD Mk2 A/C housing and molded numbers.
* [ ] Prefer an intact RHD donor HVAC assembly.

## 3. RHD refrigerant pipes and hoses

For your **GU engine**, these are particularly important because the refrigerant routing changes across the firewall on RHD cars.

* [ ] **192 820 741 — RHD refrigerant pipe, condenser → evaporator**

  * ETKA position 22.
  * Explicit RHD counterpart to LHD `191 820 742 A`.

* [ ] **192 820 743 — RHD refrigerant hose, compressor → evaporator**

  * ETKA position 30.
  * Explicitly marked RHD.
  * This is one of the major pieces I would try hard to obtain from an original RHD Mk2 A/C donor.

### Not applicable to your GU unless configuration changes

* [ ] `192 820 741 D` — RHD fluid-tank → evaporator pipe

  * ETKA associates this version with **1P**, not your GU.

* [ ] `191 820 743 E` — refrigerant hose, marked RHD but also specifically **1P**

  * Not the primary hose for your original GU configuration.

## 4. RHD condenser

* [ ] **192 820 413 E — RHD A/C condenser**

  * Explicit RHD version.
  * LHD version is `191 820 413 E`.
  * For a factory-correct restoration, this is the condenser ETKA calls out for RHD.

## 5. RHD dashboard / air-distribution parts

Your car is already RHD, so some or all of these may already be present. Inspect what is currently in the car before buying duplicates.

* [ ] **192 819 363 A — RHD air-guide housing for centre vent**
* [ ] **192 819 723 — RHD left air hose**
* [ ] **192 819 724 A — RHD right air hose**
* [ ] **192 819 043 A — RHD air-guide channel**
* [ ] **192 819 045 A — RHD fresh-air/heater controls assembly**
* [ ] **192 819 353 A — RHD air-distribution housing**
* [ ] **192 819 831 — RHD control-lid cable, 668 mm**
* [ ] **192 819 835 — RHD defroster-flap cable, 448 mm**
* [ ] **192 819 837 — RHD temperature-control cable**
* [ ] **192 959 263 A — RHD series resistor**
* [ ] **1H2 819 031 B — RHD heater core**

These are RHD-specific pieces, but many belong to the ordinary RHD heater/ventilation system rather than being unique to A/C.

## 6. RHD A/C vacuum-system routing parts

The A/C HVAC box uses vacuum-operated functions, so don't overlook the vacuum plumbing when buying a donor setup.

* [ ] **N 020 139 1 — 4 × 1 vacuum tube**

  * RHD installation uses a **700 mm** section.

* [ ] **191 823 567 — black clip**

  * ETKA specifies **2** for RHD.
  * LHD uses a different bracket (`811 611 797`).

Also obtain the shared A/C vacuum equipment:

* [ ] `191 820 601` — vacuum reservoir
* [ ] `171 820 609` — reservoir grommet
* [ ] `433 862 117` — non-return/check valve
* [ ] `2D0 129 737 A` — 4-4-4 T-piece
* [ ] `058 127 561` — Y-piece
* [ ] `191 820 605` — vacuum hoses with connections, if available
* [ ] associated small vacuum hose

## 7. A/C-specific HVAC pieces that are not marked RHD but should come with the donor box

These are not RHD-specific part numbers, but they are part of the factory A/C system and are easy to miss when buying only a bare housing.

* [ ] **191 820 676 A — vacuum unit for control valve**
* [ ] **191 898 013 — mounting parts for vacuum unit**
* [ ] **191 820 677 B — vacuum unit for temperature-regulating flap**
* [ ] **191 820 677 B — vacuum unit for intake duct**
* [ ] **191 820 679 — expansion valve**
* [ ] **191 820 692 — expansion-valve insulating piece**
* [ ] **191 959 281 — evaporator thermostat**
* [ ] **191 820 281 — thermostat reinforcement plate**
* [ ] **191 820 119 A / 191 819 418 A — condensate/water drain valve**
* [ ] **191 820 139 — seal**
* [ ] **191 820 129 — evaporator/HVAC seals**
* [ ] **191 820 845 — tensioning strap**
* [ ] **191 919 383 A — A/C fresh-air/heater-control trim**
* [ ] **321 959 511 A — blower switch**
* [ ] **191 959 513 — blower-switch knob**

## 8. GU-specific compressor installation

These are not RHD-specific, but because your car originally had the **GU**, ETKA gives a very clear factory compressor arrangement for it.

* [ ] **027 260 881 — A/C compressor bracket**

  * GU/GX/RH/1P application.

* [ ] **027 260 917 A — angled compressor bracket**

* [ ] **034 903 555 B — associated bolt**

* [ ] **049 903 149 — bush**

* [ ] **037 260 921 — threaded bush**

* [ ] **027 260 937 — eye bolt**

* [ ] **068 260 849 G — 12.5 × 947 mm V-belt**

  * GU application.

* [ ] **191 820 805 — A/C compressor**

  * ETKA lists this compressor for GU/GX/RH/1P.

* [ ] **191 820 811 — electromagnetic clutch**

  * GU/GX/RH/1P application.

Plus the listed mounting bolts/washers.

## 9. Shared refrigerant-system parts to collect

* [ ] `191 820 191 A` — receiver/drier, R12/R134a listing
* [ ] `191 820 721` — compressor → condenser refrigerant hose for GU group
* [ ] `321 959 483` — pressure switch
* [ ] `321 959 139 A` — low-pressure switch
* [ ] `161 971 988 C` — 2-pin connector housing
* [ ] `161 971 989 C` — 2-pin flat-contact housing
* [ ] `191 820 422 A` — condenser bracket, right
* [ ] `191 820 405` — condenser bracket
* [ ] `191 820 409` — bonded rubber bush
* [ ] all appropriate hose clamps and mounting clips
* [ ] all refrigerant O-rings — replace with new compatible material rather than relying on old donor seals

## 10. My preferred donor-parts purchase

If you find a breaker with a factory-A/C **RHD Mk2 Golf/Jetta**, I would try to buy the following as one package rather than item-by-item:

* [ ] Complete RHD A/C heater/evaporator box
* [ ] RHD evaporator
* [ ] RHD A/C blower
* [ ] RHD intake duct
* [ ] RHD connection boxes
* [ ] RHD intermediate piece
* [ ] RHD footwell duct
* [ ] All vacuum actuators
* [ ] Vacuum reservoir and plumbing
* [ ] Thermostat and wiring
* [ ] HVAC/A/C control panel
* [ ] All flap-control cables
* [ ] Both refrigerant pipes/hoses passing through the firewall
* [ ] RHD condenser
* [ ] All line-retaining brackets and clips
* [ ] Condensate drain parts
* [ ] Firewall grommets/seals
* [ ] Every screw, clip, stud and bracket attached to the HVAC box

The **complete RHD HVAC box and the RHD refrigerant lines are the pieces I would pursue first**. They are much harder to reproduce correctly than the compressor, condenser, receiver/drier, switches, O-rings and generic hardware.

Re: Monkeys guide to AC in your Mk2.

Reply #3 – August 18, 2026, 09:08:05 AM

Crikey, that's a long list of parts!

It looks like you have most of the pieces worked out, but you'll also need a AC specific shallow glovebox and lower dash trim as the ac evaporator housing is much larger than the stock mk2 one.