Water Leak

[Andy 105 1 Cars]

Here is a puzzle. XU9J4 rebuilt engine as per my rebuild thread. A coupe of weeks ago I noticed an odd drop of antifreeze on the garage floor underneath the car. The drops appeared to be coming from the lower centre exhaust manifold stud. I removed the stud, and pressurised the cooling system to 15psi. No leaks detected and the pressure did not move in 10 mins. So, cleaned and replaced the stud with some thread sealant and thought no more about it. The coolant level in the header tank does not appear to be dropping, although it is quite hard to tell. Fast forward to today and a drop of antifreeze appeared on the floor. Drops of coolant on afore-mentioned exhaust manifold stud. There are no obvious leaks anywhere in the system. No indication of a failed head gasket( cooling system is pressurising normally but not blowing coolant. No nasty white exhaust fumes. Good compression pressures and , as the coolant system pressure test suggests , no coolant system leaks .

Any ideas gratefully received

Andy

[Gaz205 50]

Sorry I have no suggestions mate but hope you get it sorted and it's nothing too major

[Andy 105 1 Cars]

Cheers. I do not think it is major I have done nearly a thousand miles in the past five weeks , without drama except for the front cover oil seal which was a nuisance more than a problem . Under normal running, the cooling system pressurises without drama. Just this tiny drip from an obscure place . Bemused!

[Gaz205 50]

Radweld ????????????????

[Toddy 7]

Isn't there a bleed valve on the water pipe above the exh manifold?

[Andy 105 1 Cars]

Yes there is. I will have a look at that . New hose with valve, and I never needed to use it to bleed the system, so just a possibility. Thanks for the idea.

[Andy 105 1 Cars]

Checked. Not the problem unfortunately,so still puzzled

[Tom Fenton 1,541]

Is the steel water rail over the rear of the head still in place?

[Andy 105 1 Cars]

Hi Tom. No. Afraid not. No such luck. No sign at all of any weep from the HG .

[Andy 105 1 Cars]

Found it today when I removed the exhaust manifold,to put on my new Miles Horne one. To my shame, it is the core plugs in the head. I changed the ones in the block but forgot to do the Head ones. Have to do the three along the back in situ now, which will be deeply joyful. First job is to get one out and measure so I can get some new ones.