I've got a '76 F 150 with a 390 motor. I recently drained the motor and
radiator (the green of fresh antifreeze was long gone; replaced by thich
rust color soupy like water) and when refilling with fresh water got an
wanted cloud of smoke billowing from the moter. It appears that there is
oiul being blown out of the motor, on each side of the motor, which then
hits the exhaust manifolds and creates a cloud of smoke. The oil looks like
it's coming from under each head just above the front cylinder. My thought
is that once the thermostat opened and cold water was released into the
motor something broke. Is it likely for the block to crack and send oil
pumping out on both sides? Could it be that both head gaskets went bad in
the same spot at that precise time the water flow began to the motor? Any
ideas on the topic would be of help in determining if the motor is
Sounds like this vehicle was sitting awhile. With a cooling system like
that, I would expect possible coolant leaks when that thin antifreeze
is installed. It's very slippery and fines tiny openings in the
radiator and cooler core. I realize that's not your problem here
Maybe those valve cover gaskets are puking out oil. That would be most
likely in this case. Clean things off and look closer. You did not just
blow two head gaskets because of this fluid change.
on a 390 about half of the head is the intake (very narrow head really
big intake) the intakes on these leak bad when they get old and need new
gaskets. did my dads twice in 300,000 miles while he owned his.
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