Vectra coolant leak

[dave the builder]

Or maybe you think that a crack in the thermostat housing is the cause of the leak in the heater pipe junction. So the cure is to change the thermostat housing.

my first reply said the housings are prone to cracking
BUT....
only you can see if it's cracked or just a gasket fail

[terry paget]

Agreed. So I may as well obtain a new thermostat and housing assembly now, then dismantle things when I have a spare to hand.

Thanks again for your good advice.

[Nick W]

Thanks for advice, gentlemen. Taste test confirms it is coolant.
Odd it should decide to leak after 11 years service; I reckon Dave could be right, that the housing has cracked. I see on e-bay I can get a thermostat for £15, or a thermostat with housing for £23. The housing assembly will involve more connections, but seems safer route to me. Any comments?

£8 difference on an aging part with known problems? Why would you even consider not buying the assembly?

[dave the builder]

Thanks for advice, gentlemen. Taste test confirms it is coolant.
Odd it should decide to leak after 11 years service; I reckon Dave could be right, that the housing has cracked. I see on e-bay I can get a thermostat for £15, or a thermostat with housing for £23. The housing assembly will involve more connections, but seems safer route to me. Any comments?

£8 difference on an aging part with known problems? Why would you even consider not buying the assembly?

I did mention the housing was prone to cracking when Terry first replaced the wet stat ,
and I will say again ,extreme care should be taken not to over-tighten the bolts on the housing,and even torque ,or you stress the housing ,which when it heats up ,can crack
if the original housing is not cracked (just leaking from a Gasket) it may be stronger than the cheap,non OEM replacement 
hence my recommendation to examine it very closely ,with a torch and magnifying glass 

[terry paget]

Thanks to all for advice. On removing the thermostat it was clear from rusty lower screws and the appearance of the thermostat holder face that the thermostat gasket had been leaking (right again Doc), so I merely replaced the thermostat in holder. I drove the car 150 miles yesterday, no coolant loss, and now the heater works.

[Doctor Gollum]