Water leak in the valley of my V6
I'm just completing a cambelt change on my 156 V6, only to find I am losing water into the valley at the thermostat end.
I've been pretty meticulous in what I've done, good quality parts, replaced all idlers and tensioner, new water pump, plugs while I had access, I've tried not to cut any corners and bought any necessary tools rather than make do. I have to admit though that I'd not fully appreciated how the water pipe through the valley was located and sealed. I didn't disturb the water pump end, however the pipe moved in it's location at the thermostat end. The work at the cambelt end was pretty much finished before I fully understood the sealing arrangement.
Initially I lost coolant rapidly once filled, so I bit the bullet and removed the thermostat housing, cleaned up all surfaces and fitted new O-rings to the pipe and to both unions to the heads. I was unable to change the O-rings at the thermostat end, so I cleaned as much as possible and carefully applied gasket sealant around the circumference of the pipe before seating it at this end. Now re-assembled, I still have a leak, albeit not as significant as before. I can't be certain which of the three fittings is leaking as none is visible, the water tracks down the end of the block, but I am fairly certain the problem is at the thermostat end.
I am about to attack this again tomorrow - does anyone have tips on improvements I can make to the sealing? Should I be using a gasket sealant, or other product, at the points where I am able to install new O-rings? If anyone has a fix which doesn't involve further dismantling then all the better, but I'm not hopeful on that score.