312 coolant leak from right rear of engine


http://forums.y-blocksforever.com/Topic164347.aspx
Print Topic | Close Window

By russonator - Last Year
I have coolant dripping from the bell housing when the engine is running. So far I've been unable to trace the source of the leak. Hoses are not leaking. An area of the block below the temp sender is damp with coolant, but the sending unit itself is not leaking. Any thoughts on most likely culprit? Engine is a dual quad 312. Thanks.
By Ted - Last Year
Two quick things come to mind.

First, Fel-Pro Permatorque head gaskets (the blue ones) are notorious for leaking at the lower edge of the heads on the Ford Y.  Look for some kind of water or coolant trails on the block below the heads for this one.

Second would be the threads for the four intake manifold studs in the heads.  There have been instances where just one of those holes can be open to the water jacket which will then leak if sealer is not applied to the threads on the studs before installing them.  If one of those studs is leaking, the coolant typically makes its way to the back of the block along the valley cover before making its way down.
By paul2748 - Last Year
Another source could be the heater control valve.  Usually if these leak the coolant flows to the rear via the valley cover
By 312YBlock - Last Year
Here’s another one, this happened to me, check the bottom of the thermostat housing. Mine was leaking and running own the edge of the valley pan dripping off the back of the engine.
By russonator - Last Year
Ted (5/10/2023)
Two quick things come to mind.

First, Fel-Pro Permatorque head gaskets (the blue ones) are notorious for leaking at the lower edge of the heads on the Ford Y.  Look for some kind of water or coolant trails on the block below the heads for this one.

Second would be the threads for the four intake manifold studs in the heads.  There have been instances where just one of those holes can be open to the water jacket which will then leak if sealer is not applied to the threads on the studs before installing them.  If one of those studs is leaking, the coolant typically makes its way to the back of the block along the valley cover before making its way down.


It now appears Ted's second diagnosis is the correct one. I can see coolant in the right ledge of the valley cover from the front stud on back to the accelerator linkage. Presumably the plan now is to remove the intake manifold and reinstall the studs. Is there a particular sealant  recommended for this application? I was thinking Permatex hi-temp thread sealer. Also, is anything recommended on the intake manifold gaskets? Some have said white lithium grease. Many thanks to this group for pointing me in the right direction.

 

By Ted - Last Year
The intake manifold does not need to be removed from the engine to reseal the threads on the intake studs.  Removing the nut and the turtle shell will allow a pair of nuts to be installed on the offending stud and with the two nuts tightened against each other, the stud can be removed with a wrench. I typically use some Ultra-Black RTV on those threads but Permatex #2 should also suffice.
By oldcarmark - Last Year
I had a similar Leak when I started it after sitting all Winter. Dripped at back of Motor down the Bellhousing. Turned out to be the Intake Gasket at the Front crossover was leaking underneath and running down the edge of Valley Pan to back of Engine and down the Bellhousing.