Dv producing loud pop rather than tssh when on Wot.

[kelk11]

I have a forge 007p with green spring, recently and more frequently rather than the dv producing the usual tssh, i get what can be only described as a popping noise, the same noise as if you were to make a popping noise with your lips. other mods in that area are b5 v1 with jetex, n249 delete and a stage1 map. Any suggestions?

 

[Speedy Steve]

Im be tempted to open it up and check the seals

 

[kelk11]

Opened it up to find the top seal perished, going to stick the original Bosch item back on and order a service kit. Thanks for the advice.