Aircooled Volkswagen Engine Identification - VW Parts VW Parts for Aircooled Volkswagen Information from a 5/73 USA service bulletin issued 5/73: Engines with the re-manufactured symbol, a letter, a number and ending with X, indicates a VW Exchange engine. Type 3 VW Squareback / Fastback / Squareback, and Type 411 & 412 Volkswagens. We accept: COMPANY INFO . Aircooled, Inc. 379 West