Hot Rods 327 corvette engine coolant leak , Question

My buddy's RPU has a mid-1960's 327 in it. He changed out a pan gasket and now has coolant seeping from a rear/side pan bolt. I'm not familiar with "those", but is it necessary to goop the pan bolts? It seems that every other bolt on an early SBC is open to the water jacket. Or did he crack the block with a dirty thread?

TYVM, MIZ

 

are you sure its not weeping from the freezeplug?cant see coolant coming from those mounting rails.

 

oil pan bolts on the rear corvette engines do not leak coolant.
they are blind bolt holes.

 

No, it is not coming down from above or running along the pan gasket horizonal.

Oops...I was afraid they were a blind hole.

The possible cause might really suck.

THX.

 

Check the intake gaskets for leakage at front and back, this is the usual source on the small block.

 

And don't be surprised if the leak is far away from the drip, it's amazing how far liquids can travel without detection

 

NAPA sells the dye kit. A UV light to track the real source...Anyone used one of these?

 

I have never NEEDED one ...

I use one of these



It is a radiator/cooling system pressure tester.
Install in the place of your radiator cap ... pump up the pressure to 14 pounds or so and look for the leak.

Some times it takes a little looking but ... I have always been sucessful in the long run.

1 ) Look at the freeze plugs
2 ) Check around the intake gaskets.
3 ) I have seen coolant leaks around the temperature sending units holes in between #7/8 and #1/3 cylinders also.

.

 

Wipe everything really dry and use your fingers to find the leak, wipe dry, feel, look at and feel your fingers and repeat. Pressure checking it while cold is a good ideal also.

 

While looking, don't forget the 2 core plugs at the back of the block hidden by the bellhousing.

 

Also another old technique is once the engine clean and dry sprinkle a light dusting of baby powder. The baby powder will show you where it is generating.

 

I like that idea, have to file this away for future use.

Bob

 

Those are insidious and really hard to find unless you specifically are looking right up between the flywheel and block and a drop of AF hits you in the eye. Even those are relatively up higher up than the side ones, they do rot out once in a while. Every time I have an engine out, I replace those and all freeze plugs.

Bob

 

what squirrel said--water migrates a long way-only a few places for it to come from as many have mentioned--fired my FI car last week for the first time--after a while I had water on the floor dripping off the rear by the starter--suspected freeze plug or rear of manifold-crawled under it jacked up and found a leaking heater control valve dripping on the block then down--took a bit to find it as it would only leak with car running--

 

That would really suck if it's one of the plugs in back of the block.

 

i just had the same problem and the sorce of the leak was a freez plug. the coolant travled from the plug in the cylinder head to the back of the oil pan

 

Yes I had one at my shop. It works well to find a weep that migrates down the block. I had a pressure tester too which will let you know that there is a something weeping but not as much help locating a small weep.

They were expensive when they first came out but you can now get a Harry homeowner version that is reasonable enough for a back yard mechanic. The path of the leak will glow green right up to where it is coming from.