Slight Cylinder Head Gasket Leak, Serious?

[Pavesa]

Hi,

for about the last 8 months I've found that I've had to top up the coolant fluid every so often (about every 10 weeks?) - the STOP light flicking on when accelerating going up a hill. I found out yesterday that there is a slight leak in the cylinder head gasket. Just wondering how seriously one needs to take this...?

Thanks

Andrew

[xmexclusive]

Hi Andrew

No experience of the head gasket leak and its future so I will have to leave that to others. On the level sensors and water level aspect I had a weeping radiator on one of the 2.5's. It lost about 100ml every week or so. A few days after topping up when the level had dropped again I always got the warning light up every time I accelerated up hill. In the end I concluded that the level sensor was very high up in the front of the header tank and low water dragged back by the sudden movement of the car left it dry. So as long as the warning light went out again I ignored it for about 9 months until the leak got so bad that I replaced the radiator.

Regards

XMexc

[Pavesa]

Hi XMexc,

yes, the STOP light is a pretty well used feature on all Citroens!

I don't really care personally about having to keep on topping the coolant up, really I'm concerned that it has a creeping effect and eventually causes some damage. If people say it's an occupational hazard with a lot of XMs and it doesn't really matter, fine, but if it eventually causes major problems of pressure getting into the cooling system (say) then I need to know. Also, I don't really notice it getting worse. I don't have to top it up more frequently now than a few months ago..

Thanks,

Andrew

[xmexclusive]

Hi Andrew

I understand your concern about the risk of serious damage. How does the engine coolant temperature gauge behave. If it keeps around a steady 90 and does not rise when the red light comes up then the water loss probably is not a high risk. On my V6 I had regular problems with the warning light, not just when accelerating. My son in law drove it at normal speeds on a 400 mile round trip with the red light up. We cured that problem by cleaning the probe legs on the sensor in the header tank. If you do continue to drive your car in this state it may pay you to clean or change the water level sensor as they seem to collect a lot of brown crud in some cars and the last thing you want at present is false or early water level reports. My guess is that the coolant low lights at a long way less than 5% coolant loss and if the engine temperature is steady then the loss is just an irritation.
How have you decided that it is the head gasket leaking? One of the 2.5's used to dump about 100ml of water out the overflow on start up if fully topped up. A new radiator cap cured this.
As an aside between these emails I just bought another 2.5 for spares.

Regards

XMexc

[Pavesa]

Hi XMexc,

the temperature is fine - constant about 70 degrees (I think!) certainly it isn't variable - always at about the same level.

I don't think it is overflow or poor readings, I have to top it up every couple of months because I can see the level is down and this is indicated by the light coming on. I put maybe a litre of water in every 10 weeks I think.

I know it is a problem because I had it serviced last week and it dripped on the mechanic's head! He investigated the source and told me it was a head gasket leak. (I really like XM's but I'm not a dyed in the wool mechanical type I'm afraid!).

He "kinda warned me", but I must say I don't think the problem is currently serious - it has been like this for some time - but my knowledge isn't sufficient to know whether simply leaving it alone may cause a more serious problem later..

Any views much appreciated.

Regards

Andrew

[xmexclusive]

Hi Andrew

Noz & Peter N are the experts on head gasket repairs. I guess that one of them will pick up on this at some time. The work to fit a new head gasket is fairly major but will be the same whenever it is done. Head off, send for skimming to remove any warping and refit with new gasket. Even if you were to do the gasket early (now) it would be unwise not to skim the head for flatness and the cost is small (£30 ish) compared to the labour cost for removing and refitting the head.

Regards

XMexc

[Peter.N.]

Did someone mention my name? Sorry I have been away on holiday.

The only experience I have had is with the 2.1 td and I wouldn't wish that job on anybody! it took me 2 weeks! although with persiverence it is do able. I take it yours is petrol, I would think that would be easier. The haynes manual does say that you can actually remove the head with the engine in situ, with the 2.1 td it says you cant, but you can, although I think it would have been easier if I had taken it out!

It does involve a lot of work though, if I were you, providing that you are not loosing water quickly enough to cause it to boil, run it as long as you can, topping it up with rain water, otherwise you run the risk of furring up the radiator.

Where is Noz by the way? I havn't seen anything by him for a some time, I hope he is OK.

Peter.N.

[Pavesa]

Hi Peter,

thanks for the suggestions. It's been like this for some time so I'll leave it as it is for now. Thanks particularly for the tip about rainwater. I live in southern England and things get furred up really really quickly here.

No I haven't seen anything by Noz for ages either... I hope he's ok. He introduced me to the Club-XM forum and is therefore substantially takes the credit (or is responsible - no I really like my XM !) for me still having an XM!

Andrew

[Niek]

Hi all,

I read somewhere (that's the internet problem, I never remember where I find the info or if it's good ) that the pressure release for the coolant cap on a 2.5 is higher than that of other Xms. Can anyone confirm this?
I think I need to replace mine.

Cheers,
Niek

[DerekW]

Hi Pavesa,

The fact that water dripped on your mechanic's head suggests that the gasket is leaking between an internal water passage and the outside. In that case, provided the leakage rate is only slight there is no danger and you can safely ignore it. It might be worthwhile putting in some Holt's Radweld, that might seal up the hole!

The danger comes when the leak is between a water passage and a cylinder. Water can then find its way into the cylinder and thence to the lubricating oil, there is also the danger of a hydraulic lock on startup which can do major damage. The signs of an internal leak of this sort are usually exhaust gases appearing in the radiator and emulsified oil in the sump.

Cheers,

Derek

[Pavesa]

Hi Derek,

thanks for the information. I'll print off your info and give it to the mechanic so he can take a look. Much appreciated. Great to be able to get this kind of advice from you guys.

Best wishes

Andrew

[Pavesa]

I really appreciate this site's help with my XM - I can't think of another car I'd practically like to own. Personally, I'm not into car mechanicals but it is very very helpful to be able to tap into knowledge here. By way of reciprocation, I'm pretty hot on computers if anyone ever needs a word of advice!!

Best wishes

Andrew

[xmexclusive]

Hi Niek

I got a replacement rad cap for a 2.5 a couple of years ago. To be sure about pressures I obtained a Citroen part and recall that it was cheaper than I expected.
I found the packet that it came in. (I throw all the original citroen packaging labels in a box as a filing system in case I need to get another one as I find some difficulty in communicating my requirements to the local parts dept.)
It is described as a BOUCHON and the part No. is 1306.C7

As an aside it recently took 4 visits over as many weeks to order a special tool to remove the injector with the electrical lead. After defeating " we do not sell citroen tools to customers" we proceeded through "its not in the catalog" to "this is a photocopy of the workshop manual page and thats the part number of the deep socket I want" to "Ive been down and spoken to the fitter and they have shown me the tool but there are two different sizes of them" At this stage the catalog is studied for quite a while and then I am given a piece of paper with a number that is totally different to the one in the workshop manual. I express my doubts and insist on photocopies of the tool catalog pages to take away and study at my lesiure. I find that there are 2 different socket tools 23mm and 28mm. The code number is for the 28mm one. I lift the bonnet and measure my injectors at 23mm. I check the code and find it has the entire workshop manual code plus a couple of extra letters at the start and finish. I have ordered one and its now been on back order for about 6 weeks. Will it actually arrive? If it does will it fit? Its all Noz's fault if he had not said that he had cleaned his injectors I would have been happy to carry on with dirty ones.

Regards

XMexc

[mebedforduk]

RE Injector socket

I got as far as giving up on Cit and going to Halfords and buying a deep socket that I plan to put a slice in with Mr Angry Grinder.


Not done it yet but I would assume that as long as I get the slice in the rght place it should be OK.

Cost me about 4 of 5£

Recon Injectors = new car. My 2.1 is far far better than my 2.5 after I had new injectors fitted

mark

[noz]

Hi guys,

Sorry I've been out of touch recently. I've been going through the trauma of starting a new consultancy business and it has taken up all of my available time so the old Citroen hobby has had to take a back seat I'm afraid. The XM has also had to take a back seat and its beginning to show.

There's a few issues being talked about on this thread. Let me chip in my twopennyworth:

2.5's and head gaskets
I've now done three and getting pretty good at it. Now that I know where all the bolts are its not too bad. At my third attempt I had the head off in about 8 manhours. That might not sound too good but its great when you consider it took about 24 manhours the first time. Its not for the faint hearted though. Unfortunately I didn't take photos so any self help file would be text only. I can create one if someone has the need. When the head is off it would be crazy not to do the big ends, valves, stem seals, gasket and head set, timing belt at the same time. In order of probability, water loss will be due to Radiator(s), Heater Matrix and lastly Head Gasket. Check them out in that order.

Radiator cap
I had to replace mine on the blue 2.5. The reason was that the oil contamination in the water attacked all the rubber components. I lost the radiator cap gasket, the water level sensor o-ring and the top hose from the radiator. When I bought it, the part number was the same as that for a whole range of Citroens.

Radweld
There are conflicting views about any radiator sealant. One thing is for sure. The 2.5 cooling circuit is knife edge in terms of capacity. Both the oil cooler and the intercooler dump their heat into the cooling system as well as the engine itself. The half radiator in front of the main radiator is a nonsense. the designer needs to be shot. If the radiator is fouled inside (which it will definitely be to varying degrees) then adding any kind of coagulant like Radweld will narrow the internal passages even more. You may solve the leak but you may create a heat trnsfer problem which will eventually lead to overheating and cylinder head warp. Its a vicious circle.

Injectors
You'll see from other posts that I advocate strongly the maintenance of your (diesel) injectors. They contribute the largest influence on economy, starting and general power. In the case of my silver 2.5 a faulty injector lead to one piston overheating so badly that it started to break up in the cylinder. Have your injectors checked and if necessary replace the nozzles. I paid £17 each, fitted. Slicing a socket with an angle grinder is the best idea. Use a cutting disc instead of a grinding disc because its thinner. Start with a 6-point socket as opposed to the 12 pointers. The slot weakens the socket so you need more flat area to grip the injector. The 12-pointer will just expand and the socket will slip on the corners of the hex.

Hope this helps.

This is a bit of a rambling thread. Can I ask if any of the items need to be explored in more depth then a new thread is started for each. It makes finding the information in future much easier for someone with the same problems.

Cheers

noz

This post has been edited by noz on October 22, 2005 12:15 pm