My 70' 1600 over heated a month ago on a trip to Julian. It appears that
the coolant was being pumped out to the overflow and then out of the
overflow. ( an expesive cuppacino machine). I had to stop every 50 miles
when the coolant got low enough to raise the temperature. Then I had to
drain the overflow and pour it back into the radiator. I feared that it was
a head gasket leak. The temp needle covers over the fahrenheit symbol during
normal driving.
My radiator has a 14lb cap on the top (w/ no second gasket) The overflow
has a 12 lb cap. The heater core is disconnected. I was wondering why it
would pum out the coolant instead of the air since the overflow line is at
the top of the system. I tried switching the caps around, and putting a
spare 16lb cap on the overflow but no change. It kept pumping out the
coolant.
When I got home I went and purchsed (2) 7lb caps , tried this, but no
change. I took of the tower cap while idling and a few bubbles came up.
When I held the revs up, I got a pretty good sized head building up at the
tower. Not good news. I checked the oil and it looked clean, I have not yet
pulled the spark plugs to check the chambers.
Searching for a temporary fix, I kept trying several radiator cap
combinations to "burp the system while driving". I noticed that since the
overflow tube that comes out of the side of the cap neck is welded shut on
the 1600 radiator, It didn't matter what pressure rating the cap was, since
the secondary seal on the cap would seal the system. I finally found that
keeping the 12 lb cap on the overflow and putiing a 7lb cap(w/secondary seal
removed) on the radiator, allowed the combustion gas to escape withot
pumping out the coolant. I have not overheated since, but I'm not sure where
the coolant will go if it were to overflow. Technically it would escape from
the top of the radiator, but I have tried this combination with a 2lb lower
rated cap on the radiator, and coolant still went through the overflow. This
is the same time that I installed a radiator shroud and i have not lost
coolant since. The temperature gauge does not show any difference with the
addition of the radiator shroud. Anyway, its a temporary fix as I'd hate to
miss Solvang, since this is my first year with my roadster.
Steve
70' 1600
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