Running Temperature

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Allanxantia
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Joined: 21 Jun 2005, 03:17
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Running Temperature

Post by Allanxantia »

Contrary to my previous post I am not convinced that the head gasket is away. I flushed out the radiator last night and checked the thermostat etc. After refilling and bleeding the coolant I cannot get the car to overheat at all now. Could an air lock have caused the overheating and pressurising of the coolant system?

Also what is the normal running temp of a 1.9TD?
2002 C5 V6 Exclusive auto LPG
1997 Xantia TD SX £200 bargain
1993 Xantia DLX (now dead)

Then after a 10 year Citroenless gap

1995N Xantia Activa
boroboy

Re: Running Temperature

Post by boroboy »

I've suffered from an air lock in the past (Rover 214 sei), after changing the coolant though, once I'd bled system, car never overheated again.
Must be theoretically possible to get an air lock?
Keep an eye on the water & temp, see how it goes. Fingers crossed.
jeremy
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Post by jeremy »

An air lock can cause overheating - and pressurisation but when hot only!

Pressurisation is of course caused by gas in the cooling system. If the thing is bled perfectly - there will be a little which was dissolved in the water - which will largely come out the first time the first time the engine gets hot.

If the car boils - there will be a massive amount of gas to be released - but this is because the engine is so hot that it is forming steam. While its running it is possible for some steam to be formed due to local overheating but of course as the engine cools it all condenses. Citroen engines don't seem to suffer from these problems.

So if there is pressurisation outside these circumstances it must be a gas other than steam, or what was there in the first place - so where is it coming from? There aren't that many ways it can get into a system running at pressure - so its likely to be through a joint intended to be gas proof - and about the only one on your engine is the cylinder head joint.
jeremy
Allanxantia
Posts: 138
Joined: 21 Jun 2005, 03:17
Location: Scotland
My Cars:
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Post by Allanxantia »

I did a little more investigation tonight. Temperature guage can move up quite quickly from 90 to 100 with some on boost driving. You can watch it move. I also used an old volvic 1.5L bottle as a header tank and could see a very fine fizz coming out the coolant/water and when I revved it, larger bubbles which didn't seem to stop. It must be the head gasket. How long will it hang on?
2002 C5 V6 Exclusive auto LPG
1997 Xantia TD SX £200 bargain
1993 Xantia DLX (now dead)

Then after a 10 year Citroenless gap

1995N Xantia Activa
Peter.N.
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Post by Peter.N. »

The average life expectancy for an XUD head gasket is about 150k so if its done that sort of mileage you can expect some leakage. The most important thing is not to let it boil or there is a very high risk of cracking the head. Unless the water loss is very great its quite safe to drive it but if it has done that sort of mileage it probably needs a new radiator, this hot weather will really show it up.
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