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Discussion Starter #1
Slightly odd overheating/coolant spewing problem.

Suffering coolant loss and cannot locate any leaks. The rad was changed for a brand new Valeo unit last year - it had a slight leak, though the car had never overheated until last week. It seems to use coolant, but has no signs anywhere of water loss. I have removed the undertray and the air filter box to allow me to see all the coolant pipes and connections. No signs. If I fill the expansion tank and allow the car to idle, the coolant circulates correctly and reaches 3/4 on the gauge when the fans kick in and the gauge returns to 1/2.

There are no running problems. But the coolant disappears over a couple of days. If the car is driven for 20 miles, the coolant pressure cap has released water and drenched the local area.

I suspect the head gasket. There is no oil in the coolant or vice versa.

Am I right?

Cheers!
 

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I don't think its normal (certainly its never happened on any car I've owned) for the gauge to go beyond halfway when the engine has warmed - the fans shouldn't be cutting in to bring the temp down when the temp gets high- I would say that the fans should come on once the engine has reached its normal operating temp, and stay on until the engine is switched off.

Probably no help to you, but just my first reaction upon reading your post.

Paul:)
 

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hi m8:) , have you tried changing the coolant cap,and see how it goes, somtimes you find that if there is a trace of oil in the watter it recks the seal in the cap,also if it has overheated and the cap has released the presure, you may have to replace the cap also.
you still have to find the cause of the over- heating but if the cap is goosed then it should stop you loosing coolant., the most common faults are(goosed thermostat/housing,water pump/ seals,inlet manifold gasket,split or cracked hoses,poor pipe connections, radiator,or the last option head gasket failure)
also if the coolant has ran realy low remind to bleed the system aswell as air locks can cause problems aswell

let us know how you get on and good luck alex.:)
 

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Discussion Starter #5
Will do. Cheap enough and the easiest thing to change.

As far as the fan cut in temp is concerned, it is correct. This has been the same for the last 3 years of ownership. This also applies to my Omega. The fan cut in temp is higher than the normal running temp, and has a 10 degree hysterisis.
 

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Sorry I have to disagree Vel. Primarily the thermostat (range 89C to 99C) is used to control the engine temperature and will open and close to regulate water flow to the radiator. Once a certain temperature is sensed in the radiator via the cooling fan sensor the fan will cut in and run until the coolant temperature drops. The fan usually kicks in when temperature reaches 99C and cuts out at 96C.
Cars with aircon can be different depending on running conditions as they tend to have a 2-speed fan.:)
 

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Discussion Starter #7
Not good - fitted brand new rad cap on Saturday.

Have had to add 2.5 litres of fresh coolant since.

No leaks, no overheating, no oil in the water or vice versa.

Looks like headgasket. The head isn't the problem - it's arsing around with the cambelt and two drivebelts and zero hand clearance at the front of the heavily forward-canted mill that cheeses me off....
 

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Mmm...it does sound like a head gasket problem to be honest,although if it was loosing that much coolant you should be getting a misfire when you first start the car up from cold.

If possible,have a compression check done and go from there.
 

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Discussion Starter #9
That's the weird thing - no missing hot or cold, just a little steam from the exhaust.

I suspect the gasket has failed only slightly...
 

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It is unusual to loose that amount of water and for it not to have an effect elsewhere,but there are always the exceptions!:)

I think your engine will have wet liners too,so if you do have a go at the gasket yourself,you'll have to be extra carefull not to disturb them.:(
 

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Discussion Starter #11 (Edited)
Yes, wet liners.

I usually manage to twist the head and thus avoid disturbing the liners and their delicate o-ring seal....there is a dowel about which the head is "rotated"

Been there, done that!!

Wish I could remove the head without messing with the cambelt!
 

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Hi Opel Fruit

Just been reading through your thread....well done glad you found the problem,thanks for the update.

:) :)
 

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Nice work Opel Fruit!:)

Good luck with the repair and let us know how it goes.:)
 

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Discussion Starter #16
So far so good - had a funny at first with the coolant level - bit of an oddball system.

Driven 50 miles so far - the highest the gauge has been is 2 notches above the middle position...

Not used any water - so far.

Will drain/flush and add new anti-freeze at weekend.
 

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Discussion Starter #18
350 miles on - still OK!

I note that there are several 2.0/2.2 Safranes and the like on eBay with suspect headgaskets...

The only issue with mine was corrosion of the metallised parts - due to poor coolant condition in the past (it's a low mileage vehicle - the bore condition bears this out).
 
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