D5 pressurising
 

As title, I've a 2002 d5 coming to me at the weekend owner said its starting to loose coolant, roughly half a litre every 30 mile journey.
He also said there is a lot of pressure when you release the cap even after sitting over night.
My first fear is head gasket but I'm hoping you guys are gona tell me that's rubbish they don't blow gaskets!
Any thoughts?

If maintained correctly, they don't blow head gaskets but the D5 is an engine like any other and perfectly capable of HG failure if warning signs are ignored.

You sound like you're a mechanic so this should be bread and butter to fix once it's in front of you.

With an all alloy block and head the risk is less but not zero.
If you have a leak (anywhere) the pressure should be gone after a long time with cold engine
Pressure can also devellop due to flow or heatexchange problems (clogging) or ( bad waterpump) wich will locally increase the pressure on (very) hotspots and the vesselcap will release the pressure partly (with coolant)
In this instance if the excessive pressure is let off than after cooling down (without a leak) you could have underpressure wich looks like pressure with the hissing sound after unscrewing the cap wich it isnt . if thats the case its 100% no (gasket)leak but a heat dispersion problem try to squeeze the top hose before unscrewing the cap if its hard its overpressure if its soft AND hissing its underpressure
Try to rule out the most probable causes before thinking at lifting the cilinderhead

Yes mechanic by trade, I've never had a d5 head off yet and unsure how much labour is involved.
Will look at car at weekend but I do suspect head gasket and when the owner hears the cost I don't see it getting fixed.
Has anyone on here seen a d5 blow a gasket before?

i aint seen/ heared it

Thought I'd update this one, diagnoses was suspected hg failure but possible cracked head or block. Due to age and cost the owner decided not to investigate further. We purchased the car for a little more than scrap value with the intention of braking it, as it was running we used it for leaving behind when picking up customer cars for repair and still do.
We don't run it any more than 10 miles at a time as we have no need to, it does require a coolant top up of around a half litre every 50 miles or so and the expansion bottle has blackened a bit like it's getting carbon in the system.
However 8 months later and it's still running sweet, bullet proof!

Sounds like it would be worth doing the head gasket on it, as it seems to be of useful value to you!

Are head gaskets particularly nasty to do on these engines?
I must admit it's been about 15 years since I've done a head (Nissan Bluebird was last one), but I always found this one of the easier engine jobs to do. Just had to be methodical.
If a mechanic is fearing the job, that suggests it could be nasty....

Can you not fit a bigger header tank to increase range before it needs topping up?

It's not a fear of doing a head gasket I do them on many makes regularly. It's a fear of the head or block having a crack. It's a 14 year old car on 180k.
Thing is nobody has heard of a gasket blow on one of these so it's a gamble if a gasket cures it or not.
As long as it runs it will do the job we currently use it for, we will break it into what I paid for it when it eventually gives up.