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Discussion Starter · #1 ·
Just rebuilt the short block in my 70' GTO. Since break in, I have driven about 12 miles around the neighborhood. Here is what I have noticed: Drivers side exhaust emits cloud of blue smoke on startup, thins out after a minute or two. Car runs cool, no sign of overheating. 60 lbs oil pressure cold, warmed up at idle, hangs around 30 lbs. Power is good. I was routinely checking the oil to see if it was down, but it registered between the "full: mark. No sign of antifreeze in the oil. I then opened the radiator cap and found the oily antifreeze. I can't imagine how the oil is getting into the radiator. Anyone have any suggestions? Phil
 

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Discussion Starter · #6 ·
Today I drained the radiator and flushed out as much oily foam as I could. To answer the question about the smell of antifreeze in the exhaust, It did not smell. When I started the motor, I watched through the radiator neck and when the thermostat opened, a lot of oily foam started to bubble out. As the motor warmed up, bubbling increased. It appeared to me that when the pistons were firing it was pushing the foamy oil out of the neck. I checked the oil and it was still between the add /full mark. No sign of any antifreeze in the oil pan. I pulled the plugs, and all 8 were coated in a thick black film. I used head gaskets that were marked "no retorque". It has me baffled. My next item to do is a compression check and see where I stand there. Thanks so far to all. Phil
 

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Discussion Starter · #14 ·
Just did the compression test: Here are the results. #2--200 #4--200 #6--210 #8--195 #1--200 #3-- 210 #5-- 180 #7--205 The drivers side has the "blue smoke" out of the tail pipe. Could bad head gaskets be the issue? Phil
 

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Discussion Starter · #19 ·
Sorry guys, I should have made it clear that the car has a 4 speed trans. The original radiator was re cored with 4 row copper core. No auto trans cooler. I'm still flushing the radiator to get the oil out. Next is the "leak down" test.
 

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Discussion Starter · #21 ·
I pressure tested the motor after I flushed some of the oily water out. I pumped it up to 15lbs, Watched the gauge as it leaked down over a period of only a few minutes. I did the test with the plugs out, same result, could see the needle slowly move away from 15lbs. I put four spark plugs in the passenger side head, still leaked down. I put four in the drivers side head, still leaked down. I put some "Blue Devil" Radiator cleaner with oil remover, ran the motor for 20 minutes. Watched the flow through the open radiator neck, and water flowed smoothly, temp gauge only moved to the first mark. When it cools down, I will drain the cleaner out, refill the water, and conduct the Leak Down test again. A little history now. When I installed the motor I used the FelPro gasket set the original owner purchased in 1998. It came with the short block he had rebuilt and stored, until I purchased the car in September, 2021. The head gaskets are metal, with the blue sealant around each cylinder hole. The original owner installed new rings, rod and main bearings. It was not bored oversize. I found no evidence of cracks to the naked eye, and he indicated the car 99000 miles, and he decided to do the rings and bearings. I rebuilt the heads, and they were free from any cracks. I installed a Melling cam and lifter set in May, the cam was properly "broken in", and the motor ran strong for a few days, but developed a soft cam lobe. At that time, there was no oil present in the cooling system. A few weeks ago I installed a "Howards" cam and lifter set, broke in the motor, and it ran strong. Except I discovered the oil in coolant now. That's the story of how I am where I am today. Phil
 

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Discussion Starter · #23 ·
I thought about the possibility that the timing cover might be a source, since it had to be removed. The old gasket was not damaged when I took the cover off, and was replaced with a new one. Both surfaces were clean at re assembly. Still a puzzle on how oil got into the coolant system. I am flushing the radiator again today, and doing another "leak down" test.
 

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Discussion Starter · #26 ·
Thanks for your input everyone. I ran the leak test again, still could watch the needle slowly move off 14bs. I decided to throw in the towel and I will remove the heads to see if I can be a bad head gasket. To answer BearGFR, there is no antifreeze in the oil pan, only oil in the cooling system. I have attached photos of the sludge I scooped out today, before the final leak down test. Also, today I was able to see bubbling in the water through the neck of the radiator, while the motor was running. Phil Powder Ingredient Flour Whole-wheat flour Cuisine
 
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