
Not a permanent solution, but will save it from driving me insane until I can properly sort it.
Having a slightly more in depth look under the bonnet than yesterday I spotted a couple of things amiss.
Firstly, looking at the radiator something just didn't look right. How the top hose was sitting was what really drew my attention to it initially.

A little poking and head scratching revealed that it should actually be sitting more like this.

The top brackets appear to have either fallen apart of are totally missing. Strange.
I deployed a highly technical cable tie to pull it closer to the right spot until I can properly Investigate and resolve that...has at least got some clearance between the top radiator hose and fan shroud now, this was previously touching.

On the other side the shroud had worn quite a deep groove in one of the air conditioning lines too, this now has a bit of actual clearance.

Will need to see if there is any gas in there whatsoever soon. I suspect not.
Then I noticed this.

That's the state the main line coming off the vacuum pump was in. That's not going to be doing anything any favours, especially as at the very least the actuator for the EGR system is vacuum controlled, and there are lines running off to several bits and pieces around the engine bay.
Ten minutes later it looked like this instead.

Sorting this appears to have completely eliminated the hunting idle, the ever present smell of diesel and obvious white smoke on the overrun/light throttle openings. It has also made the throttle response far smoother, so that leak was definitely causing issues for a few things. Likewise the brakes definitely feel stronger now, so I think the servo was also struggling a bit for vacuum pressure before.
It looks like there was originally a plastic cover that sat over the inlet manifold etc. I'm not too bothered about that, as it's one less thing to remove for service access - if I come across one though I'll probably replace it just because I know it should be there. Definitely at the bottom of the priority list though.
While I was in the area I changed the air filter. Old one wasn't too bad so had definitely been done in the last couple of years, but for the sake of a few quid it's on my annual-ish list. Especially on a normally aspirated diesel where getting as much air into the engine as possible is always a priority!
Nice to have got a couple of small jobs ticked off which have had a noticeable impact on the driving experience.





















