Recently changed the water pump, thermostat housing and heater and bypass hoses on my EB V8 with new items.

After this a mysterious leak has developed into the valley underneath the thermosat and immediately behind the water pump. It is a tiny trickle, which after about 1/2 an hours driving leaks about 1-5 ml of coolant which pools in this valley and is lovely and green!!!

The thermostat housing and water pump gaskets are brand new and there is no visual evidence of leaking from either of these items, and there is no sign of leakage from either of the hoses either.

The leak comes from behind the flange that the water pump mounts to (backing plate for pump) and is literally a dribble.......but f__k me it is really really annoying after just having completely servicing the cooling system.

Any help would be appreciated!!!

The part that the water pump bolts to is the timing cover. Its made of alloy and can corrode easily if coolant hasn't been changed regularly, a number of people I know have found this out the hard way. If this is the problem be prepared for an expensive repair bill, a new timing cover will set you back over $800 alone, then you have the labour etc.

The 302 cleavlands had the same problem but they are steel so could be soldered. Did you use perma seal on the gaskets?

my eb this is years ago so its scetchy rusted out a water pipe under the top 1/2 of the manifold had to pull it off and was a pissy lil hole i soldered up cant remember where it went though t/stat housing from memorie cant remember i was really s**t at the time lol but was allmost the pull legnth of the engine also if its your timming case cover find out if old school windsors are the same if so let me know and ill give you one you pay post thats if they fit hope its not that though pain in the a*** job

yeah, perm asealed all the gaskets and they are definately not the bit that is leaking (unfortunately).

I think the covers are slightly different in the later models, but will find out for sure tomorrow. Mine has a casting number of 6059-BC under the waterpump flange and no other identifying feature. Otherwise I wouldn't have a clue what the differences are!

Thanks guys. Pretty resolved to spending a day changing the cover sometime soon!

as the other guy said i think the V8's have the same kind of black steel heater pipes as the 6's it comes the water pump to the rear of the engine (heater tap) then back to the thermostat housing. make sure there are no pin holes or damaged O ring's.

get a mirror and check under thermostat housing - if thermostat not locked in place into outer housing it can slip and lip can be caught between housing and manifold. when you tighten housing bolts you can then distort housing - causes annoying leak.

richie.

Just don't overpull the bolts on the thermostat housing. It is very easy to snap the ears off it with too much pressure as Barry_V found out