PLEASE TELL ME ITS NOT THE HEAD GASKET!

[jbgtatty]

Hi. Only the third time I've ever used a forum so hoping someone can help me.

Got an 2001 HDI Synergie with 190000 on the clock (when the clocks working). Been very reliable and useful but has started blowing coolant out of the header tank cap. Around town and on local journeys it seems fine and only occasionally shows signs of weeping from the coolant reservoir cap, some times none at all. On observing the engine bay immediately after a long incline on the motorway, it blows a fair bit, reducing level of coolant from 'max' to 'min', sprayed all over the engine bay. When releasing the coolant cap in this scenario there is some pressure but not a lot. Then immediately on recommencing the journey, with the coolant level indicating minimum, and the long motorway incline is tried again followed by a long descent into local journey, there appears to be no coolant escaping from the cap. On local journeys, there is no pressure on releasing coolant cap. The water pump was changed some five hundred miles ago by local garage. Could there be and airlock that's causing the problem. Temperature gauge remains fairly stable throughout.

Supposed to do a journey to southern France this month, but beginning to feel a little nervous about the car.....

If it is the head gasket, are those off the shelf 'gasket fix' additives any good?

I'm reluctant to spend much more money on the car as its worth very little financially.

Any thoughts would be much appreciated.

Regards J.

[Filberton]

Sadly it is ominous but the quickest check is with a compression test. The alternative is to see if your local garage will do a "Sniff test" i.e. they check for combustion product in the coolant. They can also pressurise the cooling system with engine of and see if pressure leaks away. (which ominously you suggest it is.
Not sure if you have heated manifolds which can leak but to be honest, if the coolant is blowing out under pressure.......

I did have this problem once with a Hillman many years ago which turned out to be a water pump impeller failure so the engine kept its cool locally but on long runs just overheated and boiled. (but temperature gauge was also a hint and you say it is not moving so again.......).

Head sealants might seem an idea and some will swear by them but there is a risk that you will end up making more trouble if they plug up coolant channels in the block or radiator.

You can sometimes get away with this for a while but the engine will be well down on power and you will need to stop regularly to refill with coolant.

Hope it goes well. Not sure what a top off job is on the Synergie but I'm sure folk will say if it is a quick or bad job.

[wrinklet1]

Are you sure its coming from the header tank? Check around the core plugs, I had a similar problem and it turned out to be a hole in a core plug. Easy to fix and cheap too. You should have some air bleeder valves on the hoses, they look like tyre valves, just put a tyre pump on one and pressurise it slightly , and look for leaks

[citro6hydra]

One thing worth checking which you haven't mentioned is the thermostat, if it is easy to access its a simple check and may save a lot of worry if it is faulty.

Just a thought.

[Peter.N.]

It does sound suspiciously like the HG but not at the moment terminal, you could try loosening the filler cap, if the leak is not to bad it will allow the pressure to escape without displacing the water, the only thing to watch is the temperature as loosing the pressure reduces the boiling point but unless you thrash it or tow with it you shouldn't have a problem, it would have to get to about 100C to boil.

I had this with the last XM I bought, the first time I did a long journey it blew all the water out, several times, I slackened the cap and its still driving OK and that was about five years ago.

Peter

[citronut]

pressurising on slow speed local running around sounds like rad fans not cutting in to me, as when your driving faster/motorway speed there is sufficient air through the rad,

were are you located

pm. sent