Reasons for Head Gasket Failure

P 2501 · Post by **P 2501** » 10 Nov 2004, 13:31

Very interesting post - thanks peter.
Chemical rad flush every 30 - 50K is sound advice.

G4EIY · Post by **G4EIY** » 10 Nov 2004, 15:21

Hi,
Chemical flush !!!
I use a 50% mixture of vinegar and tap water for this treatment, any other suggestions...
Cheers

davek-uk · Post by **davek-uk** » 10 Nov 2004, 15:31

Regularly checking hoses is a good idea. My AX went through a full set of hoses in less than a year. When the first went I should have paid attention to the others but I didn't. All failed near or around the clamps and seemed to degrade from the inside. A couple were leaking for some time, I think, before the damage (and the leak) became evident – leading me to search for other causes that were not there!
Now that we are firmly on the subject of the cooling system, I know the rad and the matrix can silt up but are there other areas that can reduce the circulation to allow the head to get too hot? Are there ways to easily install a temp gauge to monitor the head temperature or anything to warn you of trouble?
Sorry about all this, but after a series of head gasket troubles with the AX I'm paranoid and I don't want to go through the same with the Xantia (it looks far too difficult); I'd much rather detect problems before they become catastrophes.

beezer · Post by **beezer** » 10 Nov 2004, 15:38

Quite often the hoses fail at the clamps because of rust causing the clamp to cut through the hose. When I replace a hose I always use stainless jubilee clips (marine chandlers is a good source) to alleviate the problem.

CommY · Post by **CommY** » 10 Nov 2004, 15:56

Alot of times the pipes/radiators/heater matrix go because the head gasket has gone <i>slightly</i> and it is pressurising the system beyond the limits of the components. Then pipes burst, the engine overheats due to lack of water and the head gasket goes completely, head warps etc.[xx(]
A weekly check for abnormally high pressure in the coolant system is a must.[;)]. A squeeze of a larger pipe will tell you if all is OK there should be a little pressure, if the pipe is hard you have a problem.

prm · Post by **prm** » 10 Nov 2004, 16:29

Brian
You may live to regret that recommendation once Bernie get to see it. Wait for it !!
Not if your rad cores looked like the pic.
Did you forget to remove the pickled onions !!
Good Tip
..................................
Dave
We all get paranoid with head gasket failure. Especially when several related topics appear on the forum that may indicate forthcoming problems with ageing Citroens.
Not to familiar with Xantia cooling system. But replacing mentioned items and flushing cooling system would certainly help.
There are several after-market temp gauges available. Dare I say Hal---ds carry a reasonable range. To avoid modification, machining adaptors fitted into sender recess. Check to see the correct fitting/adaptor for your car is contained in the kit.
R

tomsheppard · Post by **tomsheppard** » 10 Nov 2004, 16:46

Watch this space! I've almost finished the software for an ecu that piggybacks the existing BX cooling system sensors. Not only does it provide a temperature gauge and fan controller but it also allows you to program cut in and alarm temperatures with the useful add on that you can test the cooling fans and, should they fail, it will adjust the red and yellow alerts to the fan cut in temperatures. It is currently running on the coffee table and should be finished for the Northern Meeting.

Post by **Jon** » 10 Nov 2004, 16:57

Tom that sounds terrific! I was actually just going to make a post asking about retro fitting a temp guage to my BX, your ECU sounds like just what's needed.

bxbodger · Post by **bxbodger** » 10 Nov 2004, 17:32

This is what I have-http://www.speeding.co.uk/acatalog/Car_ ... r_166.html the electric version. I didn't get it from here, mine came from Ripspeed, but these people are doing it a bit cheaper.
Mine was £29.99, an hour or so to fit, and <b>no more engine temp worries!!!!WOOHOO!!!!!!</b>[:)][:)]

Post by **Jon** » 10 Nov 2004, 18:13

BB
I've just ordered one from the above £26.99 delivered, thanks for that. Where did you mount yours? I was thinking of putting it where the ashtray lives.
One other question, in the thermo housing I have 2 sensors, one with a grey connector, and the other is a green sensor with a yellow connector. Which one should be replaced with the sensor for the gauge unit?
Thanks!

Peter D · Post by **Peter D** » 10 Nov 2004, 18:15

I was talking to a pug main dealer mech doing a service and cam belt change and much to my surprise he had removed the cam i.e. the head bolts to inspect the cam and followers. I ask him about the head gasket and to they just tighten the head back down. Gasket failure I thought, No he insists he has never had one fail and uses the standard torque angular tighening. He recons the bolt are often on the loose side when he undose them anyway so re doing them helps.I was aware of this as I have keeped sever VW petrols and I always re torque the heads down but I do not undo all the bolt I just back them off 1/4 turn and torque then down to a figure obtained by testing one midhead bolt to the standard tighening then establishing the actual torque. I have never failed to find loose bolts. I also do this 5K after having a head off for seals or what ever and surprise surprise 3 or four of the bolts will tighten down. Loose bolts of course lead to busted gaskets. Regards Peter

Post by **Jon** » 10 Nov 2004, 18:26

Just answered my own question re sensors, one is obviously yellow warning light on dash and the other the red and stop!
Behind the fuel filter in the thermo housing is a tapped hole.(currently blanked off) On the ZX TD this is where the temp gauge sensor goes, so I am going to order ZX TD 133827 temp switch and fit, thus giving me the benefit of the gauge plus both warning lamps [:)]

tomsheppard · Post by **tomsheppard** » 10 Nov 2004, 18:29

Citroens having stretch bolts, is it wise to retorque them? I'd have thought not but then again, do they keep stretching?

Kowalski · Post by **Kowalski** » 10 Nov 2004, 18:49

Every time you tighten a stretch bolt it stretches, its part of the tightening process. If you do it more than once they'll get too long and either the bolts will snap or you'll tighten them in their threads without clamping the head down fully.

tomsheppard · Post by **tomsheppard** » 10 Nov 2004, 18:55

Thanks Kowalski. I reckoned that this was a fit and forget job. Takes us back to keeping the cooling system in good nick.