: What could it be?

08-29-09, 10:52 AM
I own a 1997 STS with the 4.6L. The head gaskets have been replaced about 1500 miles ago and heli-coiled block. Now I have a coolant leak seemingly coming from between the tranny and engine somewhere. Are leaky freeze plugs common? Also, who knows a little something about a thing called an "oil distribution plate"?? seal and is that a big job? Mine seems to be leaking oil onto the exhaust pipe and smellin' up the place. I'm new to the whole "Cadillac Experience" any help would be greatly appreciated. Thanks

08-29-09, 12:08 PM
There are no freeze plugs. Is the leak between the firewall and the engine? There are two coolant lines back there along the head that tend to corrode and leak. They are a PITA to get at.

Yes, the oil distribution plate is a very big job. You have to drop the drivetrain.

08-31-09, 09:01 PM
Hi Ranger,
I was told that the anti-freeze seems to be coming from between the engine and transmission, is it possible that the leak you spoke of is dripping in that area? If so I'll let my mechanic know what to look for. What would be a tell-tale sign that the oil dist. plate is shot and what does it do. Mine is dripping down onto the exhaust under the car and burning off. Thanks Alot!! Frank

08-31-09, 09:20 PM
Possibly a bad seal on the coolant crossover where it connects to the rear head.

08-31-09, 09:23 PM
Hard to say where the leak is from your description. I too was thinking crossover. Not likely the pipes I was talking about.

I am not 100% sure what the oil distribution plate does. I think anti spray or something like that maybe. It's located at the halfcase so if it where bad you'd have a halfcase leak I believe.

09-02-09, 10:02 AM
Thanks guys for the info, it will be very helpful! Frank

09-02-09, 01:53 PM
The oil distribution plate is a maze of oil passages to engine parts, bearings, channels, gosh-knows-what-else. It is sandwiched in the engine crankcase below the half case (a one piece 4-bolt mains casting and stud girdle) and uses formed O-ring type "gaskets" for sealing. The entire engine must be removed from the car, inverted, and taken apart. The distribution plate is the part, about 4 pieces up from the bottom, in the first line drawing, and sits on the flat in the second drawing, formed by the halfcase bottom at the 4-bolt surface shown.

Not fun, not fun at all. Very, very precise and tedious work.