Using water and top hose is realy hard like it is under pressure but no water in the oil
a reed896: There are a number of potential areas which will cause the symptom you describe. Areas to check:
1.Prior to starting, inspect the sealing surfaces of the radiator cap for cracks in the seal. Old caps will not keep the pressure in that well, consequently it causes coolant to blow out into the expansion tankwell below what the cap is rated for. Because the cap is bad, it will not function as it was designed where as it cools off, the coolant is drawn back into the radiator from the expansion tank.Top off the radiator, but leave the level about 1/2 inch below the neck but not to the top of the radiator if possible.
If the cap is in poor shape, replace it before proceeding.
Put the cap back on the radiator and position it in it's normal locked position. Start the engine and run it for 30-45 seconds then shut it off. Carefully open the radiator cap. If there is pressure in the system, this is not a good sign. Close the cap again and run the engine for a little over a minute and recheck it again. If your findings are the same, but it seems as though the pressure has built up noticeably more, you probably have a blown head gasket.
Head gasket failures don't always put water in the oil. It depends on where the gasket has failed.
2. If no problem is found, proceed with the next test. Start and run the engine and wait for the thermostat to open. What you are looking for is the top and bottom hoses will both be hot. The radiator will also feel hot and uniform in temperature across the entire surface. If after a few minutes the thermostat has not opened, only the top hose will remain hot while the bottom will be cool. If this is the case, you have a bad thermostat and it needs to be replaced. Typically if a thermostat does not open, the pressure in the cooling system will build rapidly after a few minutes and the top hose will appear to be very hard because of the pressure build up. The lower will also be relatively hard as well.. but it will be cool to the touch.
Look at these things first and if you come up empty, I'll lead you on to the more complicated testing.
Apr 20, 2009 |
1995 Isuzu Trooper