Idling problem

[h100vw]

The bypass mod was done to stop them from bursting. The later cores were better made and didn't blow. You should be able to get some new ones from VW or maybe Imparts.

Gavin

[Golf Loon]

If the core bursts it can burn your passengers legs in extreme cases. Unlikely though and as Gavin says the later cores were better made, so if it has ever been changed, you should be ok.

I have heaps of the bypass bits here if you get stuck.