leaking head gasket

J

j.grif

Junior Member
Milky oil on dipstick on 21 stud flathead. Looks like a leaking head gasket,but how to find out which side is leaking on this dual system??
 
I think that by checking your spark plugs you can see if one or two are wearing different than the others.
 
41Joe said:
I think that by checking your spark plugs you can see if one or two are wearing different than the others.
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x2. The plug in a cylinder that is ingesting coolant will look clean, not the soft brown or slightly sooty black. Same with the combustion chamber/ piston top, they tend to get steam cleaned. I have also had some luck using an infrared thermometer, the head had localized hot spots at the leaking cylinder. I was not working on a flathead but think it should still be true.
 
Check the pan rail, I have a 1937 LB block that has expansion plugs on the pan surface... they will corrode after the first seventy years or so... They may be the first thing to check.

Karl
 
Remove the upper radiator hoses. Then remove the belt. Then fill the block with water till the level is up to the top of the neck. Start the engine and watch for bubbles.
 
still milky oil after replacing the four welch plug at the bottom of block. Did the bubble check as per Alabama and the right head tube had a single bubble about every 30 seconds or so. Replaced the r/h head gasket and the bubble pops up about the same. Left head no bubble. Could us info on how to pressurize the block. Thanks for all suggestions
 
Be aware that running with emulsified oil can quickly damage rod/main bearings. Once the leak is fixed and back to straight oil a reduced oil pressure will indicate damaged bearings. I've seen this with two engines, not flatheads.
 
I think you got 2 issues here.
Leaking compression into coolant and leaking coolant into oil.
Might be that the coolant into oil leak is on the other head.
Has it overheated ?
 
Water in oil does not always mean the head gaskets are at fault. Cracks in valve spring area, pan rail, combustion chamber of head, valve seat area, cylinder walls and crankcase and even waterpumps(block mount) just to mention a few possible culprits. In some cases it is difficult to locate a crack without doing a complete disassembly.
 
No, a leak from the valve spring area or pan rail or waterpump WILL NOT be demonstrated on a sparkplug.
 
Barr's pellet stop leak will stop many very small leaks that just do not need to be fixed the hard expensive way. It was common for the old time dealers to routinely put a small can in their cars before delivery to customers. It sure cut down on come backs.
 
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