sounds like a blow back from the air filter box making its way into the front wing tunnel. your air filter box is probably not sitting firmly against the side wall

What should I look for?

I had this exact problem on my D3 TDV6, turned out to be an injector leaking on to the exhaust heat shield.

That doesn't sound too good!

Would it be the same on the tdv8? Can I get to check them easy on the tdv8?

Must be fbh as it's 8 deg now and got no smoke.

I'll have to keep and eye on it and reply with temps.

UPDATE!

Well it's definatly not the fbh.

Taken the cover of and found wet on the drivers side around what I think are the injectors!!

So hit the search button and Paul's thread come up but I have no running issues, another thread come up which stated it was an oring that had failed.

What shall I do next?

I started taking the metal guard off but it looks like half the crap on the chassis leg has to come off but I hope I could be the spill rail too...

Just an update as I've found the problem.

It pouring out of the oring for the spill rail (that's what I think it's called) so should be a cheap fix but how much diesel must I have lost as it's been smoking for ages!!!

Also it's a right pain to get all the crap out to get to where you need to be.