XANTIA HDi RUNNING ROUGH

[Stickyfinger]

Cheese roll sounds better

What ??....arrrrgggg, ouch, oohfff, crack, splinter thud ?

[Huskyxantia]

[Skull]

https://www.google.com/search?num=10&cl ... xwybI,st:0

Cheers Alistair

It's off

Injectors and Fuel Rail removed, I was finally ready the head bolts were slackened (E-16 Torx - Female star socket) by half a turn (Haynes B-o-L) but the last one wouldn't budge and started to chew-up (they’re not very deep heads considering the torque values) I had a brew and reasoned (guessed) that the head lifting slightly was enough to increase it's torque load too much, so I re-tightened the first nine bolts back down and then managed to loosen the stubborn one a quarter turn, once cracked off I reverted but would say a quarter turn each bolt in the correct sequence REVERSE of attached image would hopefully avoid that last bolt giving any trouble:

HAYNES - 2C.12 PICTURE 11.31a

Once all the bolts are fully removed I was finally ready ....

I'd cunningly left the hoist eyes in situ and used long socket bars through these to wobble the head loose to clear the dowels Jim mentioned, then with an assistant holding obstructions out of the way, I lifted and rotated rearwards to clear the engine mount, then once over that I pulled forward to release the studs from the exhaust and it was free ... much joy as I released the trapped borescope mirror that was slightly squashed but still intact, more importantly No. 4 Piston was still intact

Skull's - Mirror on top of No. 4 Piston

This was soon replaced with disapointment as my initial expectation was missing ...I've only had a quick look so far but there's nothing obvious to explain the loss of compression on No. 4 cylinder ....see what you think

Skull's - HDi No. 4 HEAD - nothing obvious

Skull's - HDi Block Cylinder 1+2

Skull's - HDi No. 1+2 HEAD - coolant blockage

Tomorrow will hopefully be a more thorough inspection of the reason for compression loss on No.4 including the other side of the Head Gasket, then valves and piston bores (look good initially as I can still see honing marks on No. 3 bore).

Off for a bath ....

[mickthemaverick]

On initial inspection from that view the only part I'd be suspicious about is the apparent break in the cylinder coating ringed in yellow!

Amended from Gary's original

[Skull]

Cheers Mick I also need to keep in mind it wasn’t a ‘clean lift off’ so there may be some spots where I’ve slid and scraped/scratched the faces …not saying that’s the case with your spot as it’s hard to confirm from my bath and Mrs wouldn’t be too happy if I brought it with me for a scrub

[myglaren]

The correct place to clean the cylinder head is the dishwasher.

[Skull]

The correct place to clean the cylinder head is the dishwasher.

I wonder if Curry’s will let me try one of theirs

Try before you buy

[moizeau]

What was the headgasket like?

[Skull]

I’ll upload some better photos tomorrow after checking both sides but initially it looks ok ….

Skull's - HDi gasket

Anyone see anything dodgy here

[CitroJim]

Well done Gary Great to se the head is finally off and deep kudos for doing it outside in sub-zero temperatures!

[CitroJim]

Whilst out for a run earlier, I was thinking about this Gary...

For what's it's worth:

That coolant passage blockage looks significant and may answer a lot of questions. The blockage occurred, pressure built and that blew out the core plug.

Then local overheating may have caused the head to warp a little and caused the gasket to let go - hence low compression and leakage into the neighbouring cylinder that would account for all the smoke, even when the suspect cylinder's injector was disabled.

When cleaned up, check the head very carefully for warping and it may be a good idea to have it checked for possible annealing in that area too.

Just my thoughts. May be total rubbish...

[Skull]

....

That coolant passage blockage looks significant and may answer a lot of questions. The blockage occurred, pressure built and that blew out the core plug.....

Sorry .....False alarm Jim ....That Coolant Port for whatever reason isn't actually cut out of the gasket ....whilst there is fine orange silt in the coolant I drained, corrosion seems to be minimal.

Skull's - false port in gasket ?

[Stickyfinger]

There was "smoke" coming out of the inlet manifold on rotation as I understand it....that can only be an open valve (for whatever reason)....looking at head gaskets waterways and pistons is not a source/reason that would happen is it....time to break out the valve spring hammer...............

[Skull]

Cheers Stickyfinger my thumbs aren't that strong

but I have a tool that might suit ....it's only been used once in 40 years

[Skull]

Blasting back a month now ... Thank You all for your patience with me on what is becoming quite a messy thread

....

Not that this is necessarily the whole issue, but still strange to only see one follower failed. Low compression would result from the piston effectively attempting the "suck" part of "suck squeeze bang blow" through a closed intake valve, and fuel would still be in the chamber since it's a direct injection engine (even if it was an IDI diesel the injectors are "downstream" of the valves, in the pre-chamber).

I'd honestly give this a fair shot at being a simple rocker failure at this point, has to be worth a shot replacing it and seeing if compression returns?

Edit- having read page 11 now, nothing wrong with borescoping it but if the valve is only minutely bent it's liable to be invisible to the eye. Even if there is a witness mark suggesting it's contacted the piston I'd still risk just doing a rocker and see if it lives.

[Skull says: You weren't the only one, I think the majority would have probably tried this initially ]

I know I'm a long way down the wrong path ekjdm14 but I don't think I really comprehended what you were saying here...I may have gone off on my own wild goose chase expecting to find some damage that caused the follower to break....

__________________________COMPRESSION TEST RESULTS __________________________________

2.0 HDi cylinder	4	3	2	1
Glow Plug	wet	dry	dry	dry
COMPRESSION MAX (BAR)	4	24	23	24

Haynes manual states 25-30 BAR normal pressure with maximum 5 bar between.

Seeing as my test was done with a cold December engine I think we can say No.s 3-2-1 are healthy.

So looks like No. 4 cylinder is the culprit that's just packed up whilst I've changed the Core Plug.

Looks like a winter head-strip to discover the underlying issue ....whether she gets put back together will obviously be another matter ....

Would the variation in compression readings I took account for that being the case in point The instructions I got with the reader were very basic and didn't mention this scenario of an intake valve being closed on a direct injection diesel (if it was just a broken follower), I queried the lack of compression a few times on this thread but failed to realise the importance of your comment .... hindsight and all that ....

I might as well do an old fashioned de-coke now I'm this far in and see how I go although compared to some modern engines there doesn't seem to be hardly any carbon build up for 168K filthy diesel ...I haven't removed the valves yet ...