Updated: 13-Oct-2025
For coolant/water temperature gauge information, please go to the Gauges page.
Original coolant
Status: The original coolant has been discontinued by VW/Audi. However, if you wish to continue using G11/G48 coolant, the following are available:
You can still flush the system and use a newer coolant. See replacement section below.
Topping off coolant
Which OEM coolants can mix with which? The table below is based on VW technical service bulletin 19-17-01.
In the Car → | VW: G11 BASF: G48 |
VW: G12 BASF: ? |
VW: G12+ BASF: G30 |
VW: G12++ BASF: G40 |
VW: G13 BASF: GG40 |
VW: G12evo BASF: G65 |
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In the Bottle ↓ | Years: 1974 - 1996 |
Years: 1996 - 1999 |
Years: 2000 - 2004 |
Years: 2005 - 2011 |
Years: 2012 - 2018 |
Years: 2019 - |
G11 G48 |
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G12 | ![]() |
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G12+ G30 |
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G12++ G40 |
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G13 GG40 |
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G12evo G65 |
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![]() ![]() ![]() Do not use G12 or G12evo in whole or in part. G12evo is not phosphate-free. Mixing G30 and later coolants with G11 will result in brown coolant (normal), as well as reduced corrosion protection. |
Replacement Coolant
You can use any ethylene glycol- or glycerol-based coolant/antifreeze so long as it is phosphate- and phosphorous-free and is mixed with distilled water, if not pre-mixed. There are numerous aftermarket brands that mix with any coolant, and most coolants are now phosphate-free (if using an off- or store-brand, check the label to verify). If wanting to stick with OEM coolant, refer to the table below for information.
Coolant | Type | Base Composition | Chemistry | pH | Use in Cabriolet? |
---|---|---|---|---|---|
G05* | Low silicate HOAT | Ethylene Glycol | Amines: no Borates: yes Nitrites: yes Phosphates: no Silicates: yes |
6 to 7 | ![]() |
G11 G48 |
HOAT | Ethylene Glycol | Amines: no Borates: yes Nitrites: no Phosphates: no Silicates: yes |
7.1 to 7.3 | ![]() |
G12 | OAT | Ethylene Glycol | Amines: no Borates: no Nitrites: no Phosphates: no Silicates: no |
8.2 | ![]() |
G12+ G30 |
OAT | Ethylene Glycol with special organic corrosion inhibitors |
Amines: no Borates: no Nitrites: no Phosphates: no Silicates: no |
8.2 to 8.6 | ![]() |
G12++ G40 |
Si-OAT | Ethylene Glycol | Nitrites: no Phosphates: no Silicates: yes |
8 | ![]() |
G13 GG40 |
Si-OAT | Ethylene Glycol and Glycerol | Amines: no Borates: no Nitrites: no Phosphates: no Silicates: yes |
7.9 | ![]() |
G12evo G65 |
PSi-OAT | Ethylene Glycol | Phosphates: yes Silicates: yes |
8.5 | ![]() |
G40 has a higher boiling point, improved corrosion protection, and better heat dissipation than its predecessors. When switching to a new coolant type, flush out all of the old coolant first. If buying concentrate, mix 50/50 with distilled (de-ionized) water. * G05 is not a factory coolant, but aftermarket manufacturers & other sources list G05 as being factory-original for the first generation water-cooled VWs - incorrect! This coolant contains nitrites, which can be damaging to aluminum components. |
System Capacity
4.6 liters / 1.2 gallons
Cooling System Refill
This is how I do it (expansion tank cars):
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.
Expansion Tanks
Original tanks were transluscent plastic, which eventually turned yellow/brown. New aftermarket replacements can be transluscent or white. Beware: many have a poor fit in the bracket and/or are made from inferior plastic.
Expansion tank, without level sensor:
Expansion tank, with level sensor:
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.
Expansion Tank and Radiator Pressure Cap
All cars:
Coolant Boils Out of the Expansion Tank (coolant temp is normal, fan turns on, no leaks detected):
Faulty reservoir cap, faulty reservoir, faulty thermostat, faulty after-run thermo switch and/or relay (1988+), blocked radiator, faulty cooling fan thermo switch.
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.
North America retailer: Radiator Express
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 using the part numbers listed below to do an Internet 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).
Top Baffle/Duct
Right Baffle/Duct
Left Baffle/Duct
All three above, with A/C
All three above, with A/C
Thank you to Thomas for creating and sharing these files!
Cooling fan speed
The radiator cooling fan operates under the following conditions:
Radiator Cooling Fan Won't Turn On
Check the fan motor and thermo switch by completing the following steps:
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.)
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.
Some parts stores incorrectly list the cooling fan thermo switches as being with A/C and without A/C. This is incorrect. From 1980 through 1987, Cabriolets use one-speed fans and use the black 2-pin 95-84° switch; 1988-1993 Cabriolets use two-speed fans and use the white 3-pin 95-84/102-91° switch; A/C is irrelevant. See the electrical page for further info.
Thermostat Part Numbers
If wanting to change to the lower-temp thermostat, you must change the thermoswitch to a lower temperature version (or vice versa). The low-temp thermostat is 80°C; the matching thermoswitch is 85-80°C.
Cooling Fan Thermoswitch Part Numbers
Cooling Fan After-run Thermoswitch Part Numbers
It is important to keep an eye on the coolant/water temperature gauge in the instrument cluster. If the gauge is reading higher than normal, this is your early warning sign that the engine is running hotter than normal and is having a cooling issue.
Should you see the engine begin running hotter than normal:
If the temperature continues to rise: Pull over in a safe spot and shut off the engine; wait for the engine to cool significantly, or call for a tow. Correct the cooling issue ASAP!
Signs of overheating (usually a combination of two or more of the following symptoms):
Common causes of overheating:
Common causes of overpressurizing:
Hose from radiator to expansion tank:
Other hose information coming soon.
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.