Flathead 6 water leak

[Steve9]

I've installed my rebuilt engine in the car, added all the fluids and now theres a water leak. It's dripping from the bottom of the front cover. I don't believe it's from the water pump. Could it be that some of the front cover bolts go into the water jacket? I installed all the other in-block bolts with permatex 2, but I'm not sure the front cover was done. Any ideas?

[JACK M]

Mopars are famous for screw holes going into the water jackets. I always check every hole and use some thread sealer on the holes that go thru.

[Guest 1930]

Mopars are famous for this yes, I am not familiar with your particular engine though, maybe start pulling them out one at a time and see which is the culprit, its always possible to use the wrong bolt, one that is too long and make a mess of things but I doubt that happened.

[hchris]

I've installed my rebuilt engine in the car, added all the fluids and now theres a water leak. It's dripping from the bottom of the front cover. I don't believe it's from the water pump. Could it be that some of the front cover bolts go into the water jacket? I installed all the other in-block bolts with permatex 2, but I'm not sure the front cover was done. Any ideas?

From memory there are no water galleries in the front of the block, most likely source of the leak is the water pump; use an inspection mirror around the bottom of the pump

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[Guest DodgeKCL]

Yes on the 6 cylinder flatheads the bolts holding the water pump on go into the water jacket. There is a small trough below the pump body and this is where the antifreeze shows up first. I'ts just accumulating there from the bolts and gasket. I slather on lots of black Permatex RTV silicone rubber around the holes and the gasket when I'm putting one on. Then wait for a few days for the RTV to cure to 'rubber' and take an Xacto knife and cut it all back to the edge of the pump. Has always worked for me. (p.s. put some copper based thread grease on the bolts to keep them from rusting in the antifreeze. They can be a bear to get out after a few years. Also make absolutely sure the pin in the water pump impellor is in good shape and tight. If they have worked loose they have an annoying habit of shearing and the fan,which is on the end of the impellor shaft, rides ahead into the radiator. It's all over when you hear the clink,clink,clink.)