Have put on about 400 miles after rebuilding the engine in my 2,000 -- new
pistons, cam, distributor, etc.
The problem is that when the thermostat opens the car "blows" out about two
quarts of coolant out of the overflow tube. The car then runs about 20
degrees above normal.
The strange thing is that it only occurs if I top off the fluid level in the
radiator to the very top (leaving the overflow tank appropriately just less
than half full).
If I leave about half inch or more of air space in the radiator . . . or if I
refill the radiator after it has "blown" . . . the car runs fine at 180
degrees (I've checked it with a thermometer).
I have replaced the pressure cap and the thermostat -- no difference.
I assumed it was head gasket leak (from a compression chamber) -- especially
since I used a copper head gasket to restore the height of the head --
however, my compression is fine (only the #1 cylinder is down about 5 lbs from
the other cylinders). I have also run the engine at operating temperature
with a pressure gauge on the (pressurized) cooling system -- the needle on the
gauge doesn't fluctuate and doesn't increase.
The obvious answer to the problem is to simply leave an air gap in the
radiator. However, I would like to know why this is happening. I've owned
the car for 20 years and have never had this problem previously.
Does this happen on other 2,000's? Any ideas?
Calvin Baker
69 2,000
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