Pontiac GTO Forum banner
1 - 20 of 27 Posts

·
Registered
Joined
·
24 Posts
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
 

Attachments

·
Registered
Joined
·
729 Posts
I have had oil go into the coolant and not the other way, at least noticeably. You've got something in the coolant causing it to foam. Oil likely, but do as Poncho says and drain it, flush it, fill it with water and try again...maybe it's just oily stuff that was in the coolant passages and needs to be cleaned out.

When I have had head cracks or head gasket leaks...it also showed up in a fouled spark plug or two adjacent ones. Check your plugs for coolant fouling. That might tell you which side it's on. Often times with a head gasket leak, the radiator will burp the excess pressure coming from the cylinder leaking past the head gasket and into the coolant system. If you just have the overflow hose hanging like original...you can put it in a jug of water and see if it burbs. It will naturally burb some as it warms up, but a gasket problem will be more constant when at running temps.

Does your "blue smoke" smell like burn antifreeze?
 

·
Registered
Joined
·
24 Posts
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
 

·
64-67 Expert
Joined
·
9,018 Posts
looks like your engine is a WS ??
with a manual transmission??
I had a th400 in a 68 ram rod 350 cutlass that the cooler in the radiator burst
and antifreeze got in my OW? th400 trans and toasted it ,,,, 1983?
My first thought was a blown trans cooler and to check the trans dipstick. Coolant wipes out automatic transmissions.
 

·
Registered
Joined
·
180 Posts
Get one of these to test with:


If the test shows combustion in ur radiator then do a compression test to see which cylinder is bad. If all cylinders show good do a leak down test.

If the radiator combustion test does not show combustion gases then get a good radiator flush/degreaser

 

·
Registered
Joined
·
24 Posts
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
 

·
Registered
Joined
·
240 Posts
I've seen quite a few blown head gaskets and they all produced very little oil in the coolant. Usual result is combustion gasses in the coolant that usually raises the operating temp since the gasses displace coolant resulting in hotter running. Just a very light film present on interior radiator surfaces.

Much more common to have coolant in the oil since the coolant is under pressure and very few places in the engine where oil is under pressure to force itself into the coolant.

The ruptured trans cooler in the radiator tank still sounds like a possibility. That would force trans fluid into the coolant while engine is running, and unfortunately allow coolant to creep back into a split cooler once engine is shut off and pressure goes away. How does the trans dipstick look right after engine has been run?
 

·
Registered
Joined
·
24 Posts
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.
 
1 - 20 of 27 Posts
Top