The cooling system in my 1953 XK120 is misbehaving. It leaks rather badly on the lower right side when being driven and the fan picks up the leaking coolant and spreads it around everywhere on the right side, showering the distributor among other things. The left side of the motor shows no sign of leaks.
I dried and cleaned off the coolant and ran a pressure test on the system. In the cold, static conditions, the system held 10 PSIG pressure for well over an hour with no visible sign of any leaks. This leads me to believe that it only leaks when hot or when the water pump is moving. Wondered if anyone else has experienced this situation and ran it down to find and fix?
Did you overfill it? If you top it up, when its hot it expands and will blow out the excess. Some of us have rigged up catch tanks of various designs on our overflow tubes.
Pretty careful not to have over filled it. I see very little, if any, evidence of coolant blowing off through the overflow tube. In any event, the overflow tube runs to the left of the engine and there is a section of plastic tube which extends the tube to well behind the fan, so even if there is coolant that comes out of the overflow tube, there should be none of it that winds up on the right side of the engine ahead of the fan.
Can you run it at a fast idle and eyeball the area when it is hot? On the RH side it has to be either the stat housing/top rad hose, heater hose off the w/pump, bottom rad hose or the radiator header tank/core. If it was the water pump seal you would see anti-freeze dripping directly below the front of the pump when cold. I guess the only other possibility would be a head gasket, but again, you would think that the leaking fluid would be visible if it is being flung back over the distributor.
I have checked the area on the lower right front of the engine very carefully. The leak is on the lower stuff. With careful scrutiny, I’m certain that the radiator cap seals as does the upper radiator hose and thermostat fitting. The static pressure test would seem to confirm that the radiator is fine. Incidentally, I had the radiator recored this summer, so that should be in good shape.
Unfortunately, whatever is leaking down below gets picked up by the fan and spattered around most everything down there. I have not checked the oil, but that is easy to do and I will see if there is any water therein.
To get the complexities of the fan spatter out of the picture, do you think it would be worthwhile to start a new test by drying everything off and washing of the antifreeze that coats all the stuff, then dry it all. Next, take out the thermostat and reconnect the top radiator hose & housing then artificially pressurize the system to 10 PSI, disconnect the fan belt and run an external fan from the front, pushing air through the radiator? Then fire it up. That would give about 5 minutes of run time without the fan spatter interfering and maybe I could see something?
That’s basically what I did with the 10 PSIG pressure test, i.e. wash it, dry it, then static test it. It held the pressure and I did not see anything leaking out. Cliff
You can clean it off and take off the fan belt, then run it for just a few minutes until the temp comes up a bit, then stop it and look for leaks.
A leak that opens up when hot suggests poor radiator soldering.