XUD Cylinder Head Issues and mysterious Evolution Document

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Rhothgar
Donor 2020
Posts: 1322
Joined: 22 Nov 2004, 01:21
x 43

XUD Cylinder Head Issues and mysterious Evolution Document

Post by Rhothgar »

Evening all,

As some of you may know, my latest tribulation is the head gasket has gone on the X1 1.9TD.

Finally got the head off today and it looks, to all intents and purposes, 100% fine.

There was a corner of the gasket missing. The front offside corner of the engine just behind the fuel pump but... it doesn’t track between the coolant jacket and the outside air or between oil gallery or to a cylinder.

When the car initially went, I pushed the thermostat housing front hose back on and managed to start the car. Within seconds, the hose blew off with some pressure.

There is no evidence of any issues on the gasket in that area.

Anyway, I will be taking it to an engineer tomorrow for checking.

The valves are immaculate. Hardly any carbon build-up. I wiped the valve heads and straight back to shiny metal. One could argue that it’s overfuelling perhaps but there was never any black smoke.

The engine has just passed 100k and I’m second owner from new so I was somewhat surprised.

So into the main reason for the post, I have a pink Evolution document which states you should remove all Allen key blanking to the cylinder head and replace them with 9.525 ball bearings pressed in and coated with Loctite Frenetranch (off top of my head).

So:-

a) Is the Frenetranch standard blue thread locker?
b) do I really need to replace these Allen key plugs with ball bearings?

I’ll do it if necessary but was wondering if any of the gurus here would know the reason.

I’m thinking of changing the heater matrix whilst the head is off because it would be easier to access the pipework.

Does anyone know of any shortcuts you can take when replacing the matrix that might save a few hours or even halve the time to 5 hours?

I blew into one of the matrix hoses which connects to the nearside rear of the head and I could hear the water gurgling in the block so it’s not fully blocked but I could swear I smelled vinegar when the blower motor was switched. (I used spirit vinegar to de-rust the block). Don’t ask! I think it might be the reason the head went.

Thanks in anticipation.
User avatar
white exec
Moderating Team
Posts: 7230
Joined: 21 Dec 2015, 13:46
x 1386

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by white exec »

For the hose to blow off immediately, compression must be getting into the cooling system.
Only possible via HG, head or block. Block unlikely, unless actually cracked.
Did you ever do a pressure test on the cooling system? Was there any loss/expulsion of coolant? Were there any signs of oil (also high pressure) in it?

Could you post the Evolution document, regarding the allen screws/ball bearings?
And a photo of the HG's missing bit, and the head/block-top could help too.
Rhothgar
Donor 2020
Posts: 1322
Joined: 22 Nov 2004, 01:21
x 43

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by Rhothgar »

Not sure what the copyright rights are. Is it fair use policy?

You can always squirrel them away and remove as necessary.

Will answer your questions when I am in front of my PC rather than phone!
B934B6A0-15C1-40C1-95F3-852DA9DF94F3.jpeg
18515B16-8AEE-42C2-8BBA-62400A9C0918.jpeg
C327B325-9981-487B-998A-D64AC216D756.jpeg
5D136084-C751-4C34-9A3E-5288EA17209C.jpeg
60C910C6-8F47-4D28-8C93-3C75F14EAB13.jpeg
Last edited by xantia_v6 on 03 Sep 2021, 09:50, edited 1 time in total.
Reason: Re-ordered the attached images
Rhothgar
Donor 2020
Posts: 1322
Joined: 22 Nov 2004, 01:21
x 43

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by Rhothgar »

white exec wrote:
03 Sep 2021, 07:06
For the hose to blow off immediately, compression must be getting into the cooling system.
Only possible via HG, head or block. Block unlikely, unless actually cracked.
Did you ever do a pressure test on the cooling system? Was there any loss/expulsion of coolant? Were there any signs of oil (also high pressure) in it?

Could you post the Evolution document, regarding the allen screws/ball bearings?
And a photo of the HG's missing bit, and the head/block-top could help too.
Hi Chris.

Although I uploaded the photos in order, they seem to have reversed.

First point to make is I do not know what RPO of M728 GDL is at present. Need to check that.
Secondly, I am unsure whether this is a modification which show be done to vehicles later than RPO mentioned on the document or whether the modifications should be done to earlier engines?

Never done a pressure test on the system. It just seemed to go in a matter of a few miles. Had I have known I would have taken the radiator cap off.

Was there any loss of coolant? Well there's a question. The car been laid up for about 6 months and I only started using it again because the alternator went on the HDi. I think it did used to lose a little water.
Rhothgar
Donor 2020
Posts: 1322
Joined: 22 Nov 2004, 01:21
x 43

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by Rhothgar »

Photos of various.
Attachments
61FCD326-A373-4D6D-AC47-522015827760.jpeg
3F2EBE79-AB8C-47F9-8085-E7A737C7C26C.jpeg
88C42629-F59D-4448-A4CF-EB1611DEF606.jpeg
4BFEA95B-DAC0-4E9E-A523-B6AE3FB5B6A6.jpeg
355BD3B6-CABE-447C-8E55-B25482BC442E.jpeg
1EC681E3-EFC5-48FD-9F7E-C287045321A8.jpeg
C5D51FE2-23EC-4DBE-8864-8A281C6BFD00.jpeg
Gibbo2286
Donor 2020
Posts: 5367
Joined: 08 Jun 2011, 18:04
x 1180

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by Gibbo2286 »

It seems you have mis-read this: So into the main reason for the post, I have a pink Evolution document which states you should remove all Allen key blanking to the cylinder head and replace them with 9.525 ball bearings pressed in and coated with Loctite Frenetranch (off top of my head).

So:-

a) Is the Frenetranch standard blue thread locker?
b) do I really need to replace these Allen key plugs with ball bearings?


It says you must replace the ball bearings with Allen screws not the other way round. Knock out the ball bearings tap a thread in the hole and screw in an Allen screw using Loctite.
If you already have Allen screws in there it's already updated.
Rhothgar
Donor 2020
Posts: 1322
Joined: 22 Nov 2004, 01:21
x 43

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by Rhothgar »

Gibbo2286 wrote:
03 Sep 2021, 09:27
It seems you have mis-read this: So into the main reason for the post, I have a pink Evolution document which states you should remove all Allen key blanking to the cylinder head and replace them with 9.525 ball bearings pressed in and coated with Loctite Frenetranch (off top of my head).

So:-

a) Is the Frenetranch standard blue thread locker?
b) do I really need to replace these Allen key plugs with ball bearings?


It says you must replace the ball bearings with Allen screws not the other way round. Knock out the ball bearings tap a thread in the hole and screw in an Allen screw using Loctite.
If you already have Allen screws in there it's already updated.
Gibbo.

Nothing would surprise me at the moment regarding my ability to comprehend. I'm under a huge amount of pressure across many fronts.

It keeps on talking about tapping ball bearings in in the latter part of the document but I think that is purely to knock others out but earlier in the document it does talk about adding ball bearings only with frenetanch?
Rhothgar
Donor 2020
Posts: 1322
Joined: 22 Nov 2004, 01:21
x 43

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by Rhothgar »

To any admin or mod,

I could do with the parts list for head gasket thicknesses to I know what to order. I think if head is not warped, I shall replace with the same thickness.

Does anyone know of a UK supplier for the OEM gasket which is Reinz?

GSF do a premium kit which includes everything. I am erring towards not doing anything other than what is necessary so no valve stem seals if I can help it, it didn't smoke so I don't see a reason to change.

Also, normally I would replace tensioners for cam belt but as they are original and probably in a very good state of repair why would I need to change them? I'll spin them later to see if they are worn.

I am wondering if the water pump is OK though because of what has happened. If I can get engineer to confirm that it is merely head gasket that caused the issue then I will probably (maybe against my better judgement) replace only the head gasket and nothing more (other than heater matrix). Would also like part number for that too pretty please.
Gibbo2286
Donor 2020
Posts: 5367
Joined: 08 Jun 2011, 18:04
x 1180

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by Gibbo2286 »

What it says is. "Knock out the ball bearing, tap a thread the hole and fit a screw coated with Loctite instead," It refers to the oil gallery so I assume there have been cases where there have been oil leaks from there.
Rhothgar
Donor 2020
Posts: 1322
Joined: 22 Nov 2004, 01:21
x 43

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by Rhothgar »

Gibbo2286 wrote:
03 Sep 2021, 09:43
What it says is. "Knock out the ball bearing, tap a thread the hole and fit a screw coated with Loctite instead," It refers to the oil gallery so I assume there have been cases where there have been oil leaks from there.
Yes up at 4.2.2. and 4.2.3.

However, the very first paragraph 1 says, "Locking unused oil galleries with ball bearings instead of threaded plugs" and this is what has caused my confusion. I obviously don't understand how these documents are meant to be read. To me, that says the opposite.

I am going with what you say and not touching the plugs. I don't wish to create more work than necessary for myself.
User avatar
white exec
Moderating Team
Posts: 7230
Joined: 21 Dec 2015, 13:46
x 1386

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by white exec »

Looking at the photo of the HG, there seems to be a blow-path from cylinder to adjacent waterway, where I've marked with red lines.
HG_1.jpeg
HG_1.jpeg (28.07 KiB) Viewed 99 times
A compression leak there would allow compression to get into the cooling system, which could be enough to blow off a hose, especially if the expansion tank pressure cap couldn't cope, or was faulty.

It's not unknown for one corner of an XUD head gasket to go leaky, sometimes where the main oilway in the block feeds into the CH/camgear.
One corner of the HG does look as if it has disintegrated, and oilily.

If the CH inspection comes up good, and the block face is nicely cleaned up, a new HG should sort it.
Follow the instructions for head tightening to the letter.

XUD heads have always been prone to warping (enough to cause a HG leak) as a result of localised over-heating, often caused by air trapped in the head (insufficient system bleeding).
Localised boiling can happen if the coolant system is not properly pressurised (eg faulty pressure cap, or a leak), and this boiling can produce trapped vapour, which doesn't shift combustion heat as well as continuous coolant. XUD heads really do benefit from meticulous attention to coolant quality, level, bleeding and avoidance of over-heating.
Rhothgar
Donor 2020
Posts: 1322
Joined: 22 Nov 2004, 01:21
x 43

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by Rhothgar »

white exec wrote:
03 Sep 2021, 09:56
Looking at the photo of the HG, there seems to be a blow-path from cylinder to adjacent waterway, where I've marked with red lines.
Image

A compression leak ther would allow full compression to get into the cooling system, which could be enough to blow off a hose, especially of the expansion tank pressure cap couldn't cope, or was faulty.

It's not unknown for one corner of an XUD head gasket to go leaky, sometimes where the main oilway in the block feeds into the CH/camgear.
One corner of the HG does look as if it has disintegrated, and oilily.

If the CH inspection comes up good, and the block face is nicely cleaned up, a new HG should sort it.
Follow the instructions for head tightening to the letter.

XUD heads have always been prone to warping (enough to cause a HG leak) as a result of localised over-heating, often caused by air trapped in the head (insufficient system bleeding).
Localised boiling can happen if the coolant system is not properly pressurised (eg faulty pressure cap, or a leak), and this boiling can produce trapped vapour, which doesn't shift combustion heat as well as continuous coolant. XUD heads really do benefit from meticulous attention to coolant quality, level, bleeding and avoidance of over-heating.
Thanks Chris for looking at this. I did perhaps stupidly wipe the gasket down before the photo to clean it up and look for evidence of disintegration.

Would you perhaps mind looking at my other queries relating to part numbers etc as I flooded the post with several posts as I am trying to hit the ground running today? Just about to head off to engineer. No pun intended.
User avatar
white exec
Moderating Team
Posts: 7230
Joined: 21 Dec 2015, 13:46
x 1386

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by white exec »

Parts diag for head, which lists the OE pt.nos. for the various notched HG's, and their thicknesses (EP).
Most NFP from Citroen, but pt.nos. might help for elsewhere.
Head - parts diag.JPG
Diag also refers to balls and plugs, but likely best to ignore that bit. (I remain confused about the 100mm threaded plug #-o .)

MisterAuto (who else??) has 0209Yx HGs, from various mfrs, including Reisz and Payen.
New head bolts??
wheeler
Posts: 5112
Joined: 21 Sep 2002, 19:07
x 290

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by wheeler »

Rhothgar wrote:
03 Sep 2021, 09:16


First point to make is I do not know what RPO of M728 GDL is at present. Need to check that.
Your RP number is 6463
Rhothgar
Donor 2020
Posts: 1322
Joined: 22 Nov 2004, 01:21
x 43

Re: XUD Cylinder Head Issues and mysterious Evolution Document

Post by Rhothgar »

white exec wrote:
03 Sep 2021, 10:16
Parts diag for head, which lists the OE pt.nos. for the various notched HG's, and their thicknesses (EP).
Most NFP from Citroen, but pt.nos. might help for elsewhere.
Image
Diag also refers to balls and plugs, but likely best to ignore that bit. (I remain confused about the 100mm threaded plug #-o .)

MisterAuto (who else??) has 0209Yx HGs, from various mfrs, including Reisz and Payen.
New head bolts??

Thanks Chris. The 100mm. plug is actually the length of the M9 tap! It took me a while to realise this. As you say, note D (which I cannot see) mentions replacing threaded plugs with balls. It is most bizarre.

The existing gasket is 2 notches so I was thinking of going to 3 notches but I guess a calculation needs doing. Most garages just throw the thickest one in! So what's the point of engineering I ask...

I have measured all the clearances and they are 0.12 and 0.22 for inlets and exhaust.

I have used Jim's excellent spreadsheet but increased the valve clearances to 0.155 and 0.305 as they should be 0.15 + or - 0.08 and 0.30 + or - 0.08 so I figure that it is best to overegg them so as the valves recess more over time then I do not have to worry about them for a very long time plus extra lift on the inlets and exhaust will give 0.5 bhp more!!!

So now I am wondering if any members have these shims:-

2.88
2.89
2.89
2.9
2.945
2.97
3.03
3.06

Don't want to go to the expense of new and nearest. I did wonder whether I could grind them down on an oil stone...