Stock XUD9TE, stuck turbo wastegate. Problem?

[Deacon]

Hi,

The engine is having its headgasket replaced, old one confirmed corroded and let oil in the coolant. Since they have most of the top engine disassembled, they looked at the turbo and said the wastegate is jammed shut, probably as I hardly drive it above 3000 rpm, 98% is city drive.

My question is, can they check this with the engine off? Is it big of a problem on a stock late model XUD9TE?

And out of curiosity, should I ever decide to check it, do they need to disassemble the whole exhaust manifold to get to it?

Thanks.