Engine: Engine Coolant Leak

[fpstude]

What I am attempting to show here is the passenger side rear of the 289 engine in our GT Hawk. I am trying to track down the source of a coolant leak. All freeze plugs that I can see on the sides of the engine block are dry.



You can see traces of coolant at the oil pan bolt. There is evidence of a path of coolant down to the bottom bolt. The white object in the upper left of the photo is the oil filter.

Any thoughts you have on the source of this leak would be appreciated.

[StudeRich]

You need to follow the "Trail" to the highest Point, probably the Right Side Head Gasket, or the Rear of the Cyl. Head Block-off Plate Gasket.

Could also be the Right Side Block Coolant Drain Plug.

[doofus]

Isnt there a heater hose coming off the right cylinder head? i would check that as the outlet elbow is usually badly corroded. Luck Doofus

[fpstude]

Thanks for the input. I'll be spending some quality time with my "mirror on a stick".

[55coupe]

Good to hear your up and about my guess would be the block off plate

[fpstude]

What is, and where is the block off plate?

[PackardV8]

What is, and where is the block off plate?

At the rear of both cylinder heads. Some are plain plates, some have the water temperature sender threaded in.

jack vines

[studegary]

With what appears to be a very small leak, it may be the temperature sender itself or its mounting (screw in).

[altair]

possible source of your leak

[bensherb]

My GT originally had one of the heater hoses connected to the right side block off plate. I moved it to the water manifold and made a new thicker block off plate because the thin stock one would just no longer seal due to rust pitting and lack of flatness from over tightend bolts. The leaking looked exactly as yours does.

[55coupe]

Perry did you find the block off plates ? Because the heads are reversible you could bolt the water pump on either end

[fpstude]

Everyone, thanks for the input. The block off plate photos were a great aid. Thanks altair

I replaced the leaked coolant. Took the car for a five mile run, getting the temperature and water pressure up to normal. I then obtained the following observations:

-The edge of head gaskets are dry.
-"pipe" plugs in the block are dry.
-Heater hoses are connected to the front area of the engine and dry.
-The area around the block off plates are dry.
-The temperature sending unit is dry.

At this time there is no dripping onto the floor under the car. Wednesday the car will get a 30 mile run. This will be a good test. I know these things don't auto correct.

[JoeHall]

I'd just keep driving it as is, but keep an eye on the leak. Eventually it may worsen to the point you can find the source, or not. Sometimes leaks get worse, or better. Road wind also blows liquids around, making it hard to find the source. In any case, it's not unusual to have several drops of oil and/or antifreeze on the floor under a driven Stude. It helps to keep a large drip pan underneath, to keep the floor clean and help pinpoint where the drops are falling.

[doofus]

I would be looking hard at the water manifold about now.i have seen many instances of gaskets rotting away and coolant migrating to the rear area like yours. Luck Doofus

[JoeHall]

Reading your last post, if no drops are showing up on the floor overnight after a drive, you don't even have a leak at this point, more of a, "weep" or seepage. Good luck striving for a bone dry Stude. LOL