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4age 20v – Cooling conversion kit


5.0 (1 review)

In stock

Heater / Water fitting provision

SKU: -cool-20v-CK3 Categories: , ,


Cooling conversion kit to suit 4age 20V engines

For those doing a rear wheel drive engine install this is our type-3 4age cooling conversion kit. Cheap and easy to use these are a simple way to convert a 20V 4age to have the water inlet and outlet at the front of the engine.

Upgrades from older models: For those who have either of the previous models of cooling kit and wish to upgrade then then please see here.


Installation guide

Click to view the guide on how to install this kit.


Features and advantages

– Ease of fitment: This kit is very easy and quick to install on the engine using only basic tools. No custom modifications are required and no unpleasant surprises.

– Full bypass type cooling system: Helps to avoid air locks and is intended to avoid any internal hot spots and also help stabilise the operating temperature.

– Original water flow: Despite many misconceptions all of our kits have always used the same water flow path of the cooling part of the engine as used from original. This will be covered further in a future article.

– No external water pipes: Some rear wheel drive conversions use pipes extending all the way from the back of the engine to the radiator to transfer the water. These bulky, leak prone, more difficult to maintain and are prone to leave difficult to remove air-locks.

– Universal water outlet provision: Choice of outlet provision to suit different applications, one kit will never suit all! See the section “Parts options” for more details.

– Common thermostat: Pre-fitted inside the thermostat housing is the same type as fitted to 16V 4age engines.

– Suits original hoses: Using the supplied parts in the kit the factory fitted AE86 / AE71 radiator and heater hoses are able to be directly used. For other models it’s able to be easily adapted.

– Water pump / alternator compatibility: Suits the original 20V water pump and the alternator / bracket from any model of 4age.


Parts options

– Heater use: This kit is available with the option of a heater provision. The heater compatible kit features a water feed outlet in the rear housing, a return feed in the thermostat housing, a joiner hose to the original heater pipe and the relevant clamps. These parts completely clear the OEM knock sensor which is critical for the use of the original ECU.

– Custom options: For those who require a different size heater water feed or something different such as a turbo water feed then please make a note in the “comments” box that can be seen during the checkout and then send an email with the relevant request. Many different size barbs are kept in stock.


Development and testing

To improve on the already successful previous kit a new approach was needed. After the single longest part development time of any product to date we now have a kit that is a significant departure from not only our previous kits but also any other type offered elsewhere. To make sure this concept worked flawlessly a single prototype kit was made and fitted to the engine of a vehicle with an existing 20V conversion. This test vehicle was then used over extensive distances every day for four months.


Supplied parts

– Main thermostat housing.

– Side block off plate: includes bolts and gasket.

– Top water outlet

– Rear bypass plate.

– Top extension hose.

– Lower hose support.

– Various clamps and other components.



– Upgrade kits: For those that wish to upgrade their earlier models of kits from us an upgrade pack is available here that is supplied with only the parts needed to make the change.

– ISCV: The idle control valve needs to be relocated if a right hand heater outlet is used. This is easily done by unbolting the part, extending the hose and fitting a mini air filter to it’s intake.

– These kits are subject to minor changes such as the type and colour of fasteners used / supplied.



Additional information

Weight1.75 kg
Dimensions20 × 20 × 9 cm
Optional extras

1 review for 4age 20v – Cooling conversion kit

  1. Kole Grove

    I purchased this kit to replace an older style 20v RWD conversion kit in my AE86.
    I’m extremely happy with the whole kit. The quality of all the parts is very high. The kit is very easy to install and bleeds very easily once all put together.
    The Rear bypass plate is slim enough that it allows you to still access behind it which is a huge plus because my old set up totally blocked it. This makes getting to the upper transmission bolts, sensors on the plate and other things a lot easier with the engine in the car. It’s still tight by you can physically get to them.

    Great kit that I would recommend to anyone who is doing a 20v swap into an AE86.

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