Citroen ZX 1.9D - Citroen ZX engine overheating problem

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Mon 10 Jan 2011 17:51
Citroen ZX 1.9D - Citroen ZX engine overheating problem - McBetter

Hi

I'm hoping someone may have had a similar problem to me as the Citroen ZX seems to be renowned for overheating problems, though I can't find the exact same problem online - in most cases I can find online the air blower stops putting out hot air which isn't what I'm seeing

Our R reg (1997) Citroen ZX 1.9 Diesel started overheating about a week ago. The heating still works fine, so we were able to get the car home by blowing hot air out the windows without red-lining the engine temperature.

From looking online it sounded like it could be the thermostat, which we removed and tested and sure enough had failed. We replaced it with a new one, bled the coolant system as per the Haynes manual, using a header tank to refill with new coolant until there were no bubbles coming out of any of the bleed valves. Then ran the car at a fast idle until the fan kicked in (a few small bubbles appeared in the header tank). Turned the engine off and bled all valves again until no bubbles could be seen before removing the header tank.

We ran the car for half an hour with no seeming problems but on a longer drive back to London the temperature started soaring again, and even with the blowers on full, pumping out hot air, could only just keep the temperature away from the red. Once hot, the temperature gauge would intermittently "flick" down to about 100, then flick back up to just below the first red line, rather than moving gradually as it had while the engine was initially heating up.

Having replaced the thermostat and bled the coolant system I'm a bit stuck for ideas, can anyone suggest anything else please? From reading online, airlocks seem to be a particular problem with this car but so far as I can tell we should have managed to get rid of them by using a header tank and bleeding the system carefully.

Any suggestions very gratefully received!

Thanks

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Mon 10 Jan 2011 18:06
Citroen ZX 1.9D - Citroen ZX engine overheating problem - unthrottled
Fluctuating temp gauge is a good indicator of gas being present in the coolant (I hope it's just a dirty sensor-but it never is!). In fact it's often an early sign of the dreaded HG failure...

If the fan comes on then the radiator must be receiving and discharging hot water.I know the heater is working but I still think it's worth giving the coolant system a good reverse flush, just in case there are any blockages.
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Mon 10 Jan 2011 21:58
Citroen ZX 1.9D - Citroen ZX engine overheating problem - Peter.N.

I would take your thermostat out , put it in a saucepan of water and bring it to the boil and make sure the it is actually opening, there appears to be a batch of faulty thermostats about at the moment..

The only other cause, if your heater is working OK is likely to be a clogged radiator, try driving it with no thermostat, if all is in order it should run nearly cold, if it still gets hot I would suggest a new radiator.

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Tue 11 Jan 2011 11:49
Citroen ZX 1.9D - Citroen ZX engine overheating problem - McBetter

Thanks both for your suggestions, I know I really should have checked the new thermostat before installing it, that'll teach me. I'll do a full drain and refill of the collant as well and see what happens. Cheers.

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Tue 11 Jan 2011 16:24
Citroen ZX 1.9D - Citroen ZX engine overheating problem - Peter.N.

You shouldn't have to check new parts, I have been fortunate in not ever having bought a faulty one, so you can't really blame yourself.

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Sat 22 Jan 2011 13:43
Citroen ZX 1.9D - Citroen ZX engine overheating problem - brightonwill

hello all, I am having sort of similar problems with my ZX the gauge is not showing any temp, fans don't kick in, but after putting new thermostat in and filling and bleeding coolant, its pushing it out of the filler cap, there is not much smoke but there is bubbles in coolant its pouring out of the filler cap the whole time its started up. but the temp gauge shows no heat!? is it head gasket or is it something easier.

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Sat 22 Jan 2011 14:33
Citroen ZX 1.9D - Citroen ZX engine overheating problem - Peter.N.

Doesn't sound as though you have bled it properly, have you opened all the bleed screws and made sure that water free of air bubbles is coming out? If after doing so it still blows the water out I would suspect a faulty head gasket. The heater won't work until it is properly bled, if the heater works and then goes cold again, another indication of a blown h/g.

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Sat 22 Jan 2011 18:00
Citroen ZX 1.9D - Citroen ZX engine overheating problem - brightonwill

right so after all the water pushing out I have left it for a bit gone off had some food, come back released filler cap which had pressure in it which pushed more water out. looked in the header tank at it was at normal levels so just started it up and now run it for about 50 mins it got to normal temp and held it, no water came out of coolant filler cap but no heat came out of heaters.... has help temp at just over 90, when I bled it I released all three bleed valves and used header for the header tank (old bottle).

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Sat 22 Jan 2011 22:43
Citroen ZX 1.9D - Citroen ZX engine overheating problem - Peter.N.

If it is h/g leakage it will normally only pressurise when the engine is under load, the harder you push it the greater the water loss. If you leave it standing overnight and there is still pressure in the system, that's almost certainly what it will be.

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