if there is a problem with dv will it show up on vws computer i had my car checked b4 i bought it and it came back ok.
Yes, agreed. But not every tech at VW stealers are the brightest tools in the box. They may not actually plug in the 'puter to check!
is it worth puting a after market dump vavle on and will a mk4 18.t one fit
Forge do make one, but it is firkin expensive, requires servicing, and isn't really any better than a correctly functioning OEM valve. I dunno about the 1.8 20vT valve fitting, but the best option is to use the 'piston' valve from the Mk6 TSI engine.
