"It does, yeah. It seems that access to the bottom bolt of the thermostat housing is a bit tight and involves moving the power steering components, aux belt, etc. out of the way, something I don't have a problem with; it's the putting things back together that gets me nervous!"

I understand what you mean. Its one of those jobs where you just have to take your time or even take photos so you have a reference point to go back to.

The thermostat's on the euro 5 models (2009 onwards) are a right pain! Some genuis thought it would be a good idea to put the thermostat in the most awkward place, literally at the back of the engine! You have to remove the battery, air box, throttle body, the EGR valve, some of the wiring loom & then you'll see the part! So much so, a dealership will charge around £300-£400 to replace it! :shocked:

Quick update:

1. Thermostat housing (and thermostat) replaced (thanks @cheshired5).
2. Replacement FPR installed.

Engine cutting out behaviour unchanged (cut out during 3-point turn, engine at operating temperature).

Update:

Fuel pressure sensor replaced; engine still cutting out at coasting/idle, although it no longer takes the engine to reach full operating temperature to do so!

There are not many parts left to replace if I'm right in thinking; it's either the HP pump or the pressure safety valve. Or it could be an electrical gremlin somewhere!

Is it still possible to obtain a new HP line from the HP pump to the rail? It's supposed to be replaced upon removal, right?

Thoughts, anyone?

The high pressure lines are supposed to be replaced each time they are removed. This is because they deform when tightened in order to provide as secure a connection as possible. You can reuse them a number of times though, providing you don't overtighten the nuts. Unless the pipe is damaged or leaking I wouldn't be rushing to replace it.

My recommendation to try the FPR was based on trying the easiest thing first. It obviously didn't work despite some of the symptoms matching those created when a fuel pressure regulator starts to play up. The fuel pump is a strong possibility, but before you go near it I would pull the fuel filter and check for swarf in the filter housing. If you see any take a picture and post it up.

I would have done (and did) the same: easiest thing first.

Seeing as there are not many things left to swap out and test, and that my FPR (or inlet metering valve (IMV), as I've been reading?) came with a HP pump attached to it, I'm going to see if I can swap it out.

I'm very fortunate to have had the time and opportunity to investigate this step-by-step. But I think it's been going on for long enough and I need to know whether this will potentially cure the problem or not.

Either way, next week's school run will not be on public transport! :soccer_ball:

I've just had a look at the spare HP pump and tried rotating the input shaft by hand.

I couldn't.

Can anybody advise if that's how it should be?

Thanks.

EDIT: Nevermind, I got an adjustable spanner on it and it moved freely.

HP pump replaced and fuel lines system primed with primer bulb and monitoring return line for bubbles.

Still summoning the courage to turn the key, while contemplating what might go wrong, and more importantly, whether I'll be able to cope with it!

Good luck..... You deserve a positive outcome.

After 200 trouble-free miles on the replacement HP pump, I'm hoping the issue has been resolved.

Thread closed (for now!).