[Laguna I] Problème circuit de refroidissement

Tres interesant. Peut-etre quelqu'un peut aide.

Ok so the problem is like this.

We have one Laguna 1 V6 gasoline.
The cooling system is ok, no air inside it.
Start the engine go outside city any speed everything is ok, temperature ok, vetilator ok running when needed.

But here comes the problem. If you drive the card in the city, red light and stuff the temperature increases quite quickly and the water seems to boil. Until here ok ... BUT the interesting thing is that the ventilator doesn't start anymore. Why ? because the radiator is cold ?!??!? why ? because there is air inside circuit, a lot of air at quite big pressure ... the cooling circuit enters the radiator above and exists above ... at the entry it has one screw (vis) for getting out the air from system ... if you unscrew it a lot of air will come out and the the cooling liquid will go into radiator.

What is interesting is that there are no leakings of cooling liquid. No oil into water or water into oil.

What could the problem be ?

P.S. some says that is the trimming of cylinder head (garniture de culasse), I think that this is the problem also, but is quite a challange to replace it at V6 laguna ... so we need more oppinions.

Thank you a lot,

P.S. qui == oui - please the moderators - change the poll pleaseee

Merci beaucoup pour le moderateurs qui avait change mon topic. Quiconque savoir quelque chose de ce probleme ? Mersi

rien ? nobody knows nothing about this problem ? :?

S'il vous plait. Une deux trois responses ... quelque choses ...

Yes, the gasket may be faulty :

I would try to remove the "calorstat" before, it may be because it's faulty. If it does not open fully, on idling regime you got insufficient coolant flow and the water boils. Once it boils, there is steam on the thermocontact instead of water and so it does not close anymore. On the road, you get air from running and more coolant pressure due to higher motor regime : The problem does not occur.

Problem is, if the gasket ("joint de culasse") is leaking, combustion gas gets in the water circuit, which leads to the same symptoms (although in that case it should also happen on road). A friend of me had that very same symptoms on a relatively old R19. He tried a lot of things (purge cold, purge hot, use water-circuit cleaning fluid, totally renew coolant, change thermo-contact thinking it was not broken but lazzy, changed the "calorstat" believing it did not open enough). Never was the problem solved.
Finally he went to the mechanic. The "joint de culasse" was replaced and voilà, problem was gone.

good luck !

Merci beaucoup pour cette response.

The calorstat was removed and the problem still appear exactly as you described also.

Thank you again.