Block coolant adapter for virtually all Late Audi I5 20V blocks, feeds coolant out of the back of the block to the heater core system. CNC machined from billet aluminum, includes new bolt and o-ring seal.

This replaces later (AAN, ABY, ADU, all made from plastic) 25mm coolant adapters!

If you have an early 22mm (Pre ~ 1990 made from Metal) coolant adapter, please order our Block Coolant Adapter, Rear Audi I5 20V, Early (22mm).

Please Note: Due to the age of most blocks, we recommend a light coating of RTV on the o-ring before installation to seal up any pitting or uneveness in the block sealing surface.

Also ensure all rust and remains of old oring and housing are cleaned out of block, otherwise the new unit will not fit. These are tested and validated on a good, rust free block, if you are having issues fitting this housing clean out the block port area until it fits properly. The fitment of this part is the exact same as a new OEM unit.