Hello Folks I have a 55 S2 3200 pick up. The original mileage is now 78,000. Have spent several years restoring it and now drive it regularly. Have noticed that it "uses coolant" when I drive 50 miles or so. There is no leakage, no water in the oil and no overheating. I also have a new radiator cap - 7psi. New thermostat and radiator. I top off the radiator when I get home. It takes about two quarts to fill it. Only fill it to about 1 quart low. Can just barely see the coolant. Heater on or off hasn't changed things. It starts and runs fine and the plugs don't show any residue that would indicate water or anti freeze getting past the head gasket. No blue smoke or excessive water vapor. I'm stumped! Used a cooling system pressure tester and a CO2 tester. No problems found. Up on a lift there is no water or dampness anywhere to be seen. Does anyone have an idea or suggestion fro me as to what else I can do to? Many Thanks, Sepp
Water expands when it gets hot, of course. So there has to be some "head space" for the expansion. Unless this truck came with an overflow tank or you installed one, filling the top reservoir to the top means some will go past the pressure cap and out the overflow tube onto the ground. Once that happens the overflow will stop. So when you look at it later to find leaks there isn't likely to be any evidence since it will have dried up when driving. Try leaving it at the level you find it when you check after fifty miles and see if you still lose coolant.
If I fill my top tank to more than my index finger can reach to the first joint it will invariably have fallen to that level next time I check it. If I leave it alone it will stay at that level. Mine has a big top tank and it takes about 2 quarts to fill it from the "index finger joint" to the top.
On my ‘52 with a ‘59 235 if you peek into the radiator, you can’t see the level. I filled it a couple of times with the same result. It doesn’t overheat so I assume it’s OK. This bothers me so I’m going to keep my eye out for an overflow tank.
1952 Chevrolet 3100 Project Journals ‘59 235 & hydraulic lifters “Three on the Tree” & 4:11 torque tube 12v w/ Alternator
With a cold engine, the coolant level only needs to be at a level high enough to cover the tubes. I recommend that you remove the radiator cap while the engine is cold. Start with the coolant level no more than 1 inch above the tubes, then run the engine in the driveway until it fully warmed up. You should see the coolant noticeably rise once the engine reaches operating temperature. Put the cap back on and drive the truck like there is nothing wrong with it. With all of the tests which you have done so far, I don't think that there is. Carl