Updated: 11-Jul-2023

For coolant/water temperature gauge information, please go to the Gauges page.

Coolant / Antifreeze

Original coolant

Status: This coolant has been discontinued by VW/Audi. However, if you wish to continue using G11/G48 coolant, the following brands are still manufacturing it:

You can still flush the system and use a newer coolant, G13 being recommended by VW and Pentosin (see below).

Replacement coolant

You can use any coolant/antifreeze so long as it is phosphate- and phosphorous-free and is mixed with distilled water, if not pre-mixed (see mixture table below). There are numerous aftermarket brands that mix with any coolant, and most coolants are now phosphate-free since most manufacturers are now using aluminum radiators and other components. If wanting to stick with VW/Audi Autobahn or Pentosin brands, be aware that you cannot mix blue coolant (G11) with pink coolant (G12), but you can mix blue (G11) with purple (G12++). Refer to the compatibility table below for additional information.

OK to Mix? In The Car:
G11		 In The Car:
G12		 In The Car:
G12+		 In The Car:
G12++		 In The Car:
G13		 Years In Factory Service Contents
In The Bottle:
G11		 green check red x red x green check green check 1980 - 1996 Ethylene Glygol-based with silicates; phosphate-free
In The Bottle:
G12		 red x green check red x green check green check 1996 - 2003 Ethylene Glygol-based; silicate- & phosphate-free
In The Bottle:
G12+		 red x red x green check green check green check 2003 - 2008 Ethylene Glygol-based with special additives; silicate- & phosphate-free
In The Bottle:
G12++		 green check green check green check green check green check 2008 - 2010 Ethylene Glygol-based with silicates; nitrite- & phosphate-free
In The Bottle:
G13		 green check green check green check green check green check 2010 - present Ethylene Glygol-based with silicates; nitrite- & phosphate-free
G12++ and G13 are backwards compatible with all previous coolants.
G12+ is okay to mix with G11 and G12, but is not recommended.
Mixing G12++ or G13 with G11 will result in brown coolant, which is normal.
When switching to a new coolant type, flush out all of the old coolant first.

System Capacity

4.6 liters / 1.2 gallons

Cooling System Refill

This is how I do it (expansion tank cars):

  1. Turn the heater temperature lever to "hot". (A/C-equipped cars: turn the lower lever to "vent".) Keep the blower fan off.
  2. Remove the expansion tank cap and temporarily set it aside in a safe place.
  3. Pour in coolant until it reaches and stays at the "full" mark.
  4. If desired, use a cooling system pressure tester to push coolant into the system and/or to check for leaks (do not pump more than 15 psi into the system!).
  5. Turn the engine on and let it idle (if you used a pressure tester, remove it first!).
  6. Keep an eye on the expansion tank. Once coolant begins flowing in from the radiator, squeeze the upper radiator hose a few times.
  7. Reinstall the expansion tank cap and keep an eye on the water temperature gauge as you wait for the cooling fan to turn on. If all is well, the fan will turn on and the gauge will read normal. If it does, turn off the engine, let it cool down, recheck the coolant level, and top off if need be. Done.

Other folks have you fill the system via the upper radiator hose; this is totally unecessary (not to mention a PITA) and puts undo wear on the hose. However, if you prefer this method, feel free to use it.

If your car is having an air bubble issue, a common trick is to drill a small hole into the thermostat, which allows for internal air bleed-off. I, personally, have never had a need for this in nearly 30 years of ownership, but others have encountered air issues leading them to automatically drill the hole on every new thermostat they install. Use the method that works best for you and your car.

Not keeping up with timely coolant flushes can lead to internal cooling system corrosion. Flush the coolant every 30,000 miles or every 2 years, whichever comes first, if using G11; if you have switched to a G12 variant or G13, the flush interval is increased to 4 years.

Coolant Expansion Tank / Reservoir

From 1979-1983, Rabbit Convertibles did not have a coolant expansion tank; they had the old style system wherein the coolant was added directly to the radiator via the radiator cap. From mid-1983 to 1993, Rabbit Convertibles and Cabriolets came with expansion tanks; some 1982 models may have the bracket for the expansion tank but VW continued to use the old cooling system on most, if not all, 1982 and most 1983s.

If you would like add an expansion tank to your system you will need the following parts: newer style radiator, hose from radiator to expansion tank, expansion tank, hose from expansion tank to coolant return pipe and a coolant return pipe.

Help Icons No AttributionCoolant Boils Out of the Reservoir (coolant temp is normal, fan turns on, no leaks detected):

Faulty reservoir cap, faulty reservoir, thermostat, faulty after-run thermo switch and/or relay (1988+), blocked radiator, faulty cooling fan thermo switch.

Radiator Cooling Fan

Cooling fan component guide: Fan Guide Download

The radiator cooling fan operates under the following conditions:

Cabriolets up to 1987 with A/C do not have two-speed cooling fans; these cars have one-speed fans that are two-stage (fan is turned on when the A/C is turned on). From 1988-1993, Cabriolets were equipped with two-speed fans; those with A/C would then have two-speed, two-stage cooling fans.

Help Icons No Attribution Radiator Cooling Fan Won't Turn On

Check the fan motor and thermo switch by completing the following steps:

Help Icons No Attribution Radiator Cooling Fan Won't Shut Off

Replace the radiator fan switch.

1988-1993 Cabriolets: The after-run relay mounted on the driver's side fender may be faulty, and/or the after-run thermo-switch (back side of the cylinder head) may be stuck closed (permanently grounded).

(Cabriolets equipped with after-run systems (1988+) may have the cooling fan run up to 15 minutes after the engine is turned off.)

Thermostat & Radiator Cooling Fan Thermo Switch

Thermostats & fan switches go hand-in-hand. When replacing one, you should replace the other and both should match temperature-wise (see below). Always, always, always test a new thermostat in a pot of boiling water to ensure that it works before installing it in the car.

Switch* Temperature Ratings Turns Fan On At: Turns Fan Off At: Proper Thermostat*
Fan thermoswitch, one-speed 95-84 95°C (203°F) 84°C (183°F) 87°C
Fan thermoswitch, two-speed 95-84 / 102-91 95°C (203°F) / 102°C (215°F) 84°C (183°F) / 91°C (196°F) 87°C
Fan thermoswitch, two-speed 85-80 / 93-88 85°C (185°F) / 93°C (199°F) 80°C (176°F) / 88°C (190°F) 80°C
After-run thermoswitch (K-Jet) 110 110°C (230°F) 70°C (158°F)
After-run thermoswitch (Digi) 100 100°C (212°F) 70°C (158°F)

*Notes:

An 87° thermostat begins opening when the coolant temperature has reached 87°C and is fully open at 102°C. If wanting to change to a lower-temp thermostat, you must change the thermo switch to a lower temperature version (or vice versa). The low-temp thermostat is 80°C; the matching thermo switch is 85-80°C. Some parts stores incorrectly list the thermo switches as being "with A/C" and "without A/C". From 1980 through 1987, Cabriolets use one-speed fans and use the black 95-84° switch; 1988-1993 Cabriolets use two-speed fans and use the white 95-84/102-91° switch; A/C is irrelevant. See the electrical page for further info.

Radiator

1979-1983 ~ without expansion tank

1979-1993

1980-1983

1984-1993

1990-1993

If you desire to rid your car of as much plastic as possible, all aluminum replacement radiators can be found on eBay.

Radiator Baffles

The purpose of the baffles (aka cards, ducts) is to direct airflow through the radiator with little air escaping around the radiator; this enables the cooling system to work more efficiently. The baffles were originally made out of cardboard-like material which, over time, disintegrates. You can purchase new baffles (plastic versions) by doing a part number search. You can also easily make new, long-lasting ones yourself out of sheet metal or Coroplast (yard sign board material) from your local home improvement center. Simply Tap on the links below to download the templates (only the AutoCAD download contains genuine, full-size templates that can be printed at your local Kinko's, etc.; the others contain measurement templates for use as guides in making the baffles). Although not all baffles are listed for all years, they can be adapted to fit your particular car.

PDF

AutoCAD

Thank you to Thomas for creating and sharing these files!

Oil Cooler

Only Cabriolets with JH engines in North America have oil coolers; "why?" remains to be answered. In Europe, only the EG, JH, 2H, DX and KT engines came with oil coolers.

If your Cabriolet is without an oil cooler, you can install the OEM cooler (additional coolant hoses will be needed), or an aftermarket cooler that utilizes air, rather than coolant, to dissipate heat from the oil.