Strange Coolant Leak on Pontiac 287! Help!

Hey guys I need some help from you Pontiac experts.

I've got a leak on my 55 Star Chief with a 287 block.

The heads were rebuilt in December, all new gaskets on the top end, and new freeze plugs. I noticed a coolant leak recently coming back from Good Guys in Del Mar.

I could see the leak dripping from the lowest point on the flywheel cover.
I traced it up the block, and it looked like it was coming from the back of the drivers side head, so I figured it was the gasket and one of the head bolts in the back was slightly loose.

I pulled the intake and valley pan, and the gasket and head were great.

I found the leak coming from the back of the block, to the driver side of the distributor. It is flowing steadily from a gap between the block and where it attaches to the bellhousing.

See the attached pictures for the location.

My question is, what the hell can I do about this?
Where is there a coolant passage back there through the back of the block.
How is it leaking at this location?
Is the block cracked? Is this something I can fix without pulling the engine?

Thanks!!!!!

Evan

 

You sure it's not weeping around the freeze plug in the back of the head?

 

Double check that it's not coming out of the back of the intake. I finally traced mine back to there when mine was leaking at the same area.

The bolt that goes in where the linkage attaches is a real PITA to get to but I finally got it tight enough.

 

Thanks guys.
Absolutely positive it is NOT the freeze plug at the back of the head. The plug is brand new (as of January 1st) and bone dry.

Its not leaking from the intake either.
I pulled the intake completely off, and got a flashlight, and watched coolant flowing from the spot I'm talking about (back of the block, in a gap between the block and bellhousing).

 

I'd still have to bet that it's coming from above the block somewhere. I'm trying to remember when I had mine last apart and I can't think of anywhere it would leak anti-freeze from below the heads.

Re-looking at your pics, mine was pooling to the left of the cover bolt as seen in your pic. (further one to the left).

Only other thing I could think could be it would be a crack in the very top of the block but I'd think you would have caught that.

Your heater lines run on that side but you say that you can actually see it seeping from the two pieces? (block and cover)

 

Borrow or rent at autozone a pressure leak tester fill car up with water put tester on radiator ,pump up to about 14-16 lbs and you"ll be able to find the leak,only sure way.

 

This is good advice here...

 

I may get the pressure tester and try that,
but I'm absolutely positive the leak is coming from that gap between the block and the top of the bellhousing.
I had the intake manifold and valley pan off, and was literally watching the water trickle from that area. It's definitely not leaking from either of the heads or above the block, as I had to access to watch everything above that point.
I just don't get how it can be leaking from the there.

Those pictures I posted above are the spot. Its this gap that is between the back of the block and the bellhousing. I just didn't think there should be any coolant running there, its strange.
Do I need to separate the engine and bellhousing to track this down further?

 

Best of luck and lots of fun with that. You have to pull the engine to seperate them. I guess you can get them apart otherwise if you are real patient but then you'll never get a good look at that area.

I decided that taking the front end off, radiator and all was the best way. If I ever have to do it again, I'd do it the same way.



Just in case you haven't done it before. If you have and I'm wasting my breath, disregard. LOL

The torous (Convertor) bolts to the flex plate with like 20 some bolts. You can access them through the starter opening. But then there is like no room to get to the bolts to remove the tranny from the cover. It doesn't just pull out. The cover has to be removed up and over the flex plate.

 

Just a heads up guys.
Couldn't fix the leak, and not up for pulling the engine or disassembling the front of the car.

I tried Bars Leaks block & head repair, and it worked great.
Followed all the directions, and it sealed up the leak!