I think my water pump may have exploded. We have been having issues with what we believe is the thermostat sensor and the head gasket leaking. Which we think are causing it to not start about 25% to 50% of the time. I check and fill the oil and antifreeze daily. Today I took a small trip which was only about 20 miles and everything was fine all day until I got home. And suddenly there was a weird sound. Then a few moments later there was an explosion and steam and fluid erupted everywhere. It did not die nor stall just simply sputtered a little until I shut it off. I’m not entirely sure what the problem is nor how to fix it.
From what you described there was a small leak in the cooling system. Now there is a big leak. You will need to locate the leak and make the necessary repairs to correct it. With such a large leak it shouldn’t be to difficult to locate. Of course wait until the engine is cooled down.
Locating a Large Coolant Leak
Since you already know there is a leak just use water for locating the leak. Remove the fill cap and pour water in. Chances are before you can top it off you will see the water flowing from where the large leak is located. Most likely would be one of the hoses. Replace the hose or what ever is needed. Then test for any smaller leaks.
Locating a Small Coolant Leak
Locating a smaller coolant leak is a bit more difficult and requires a special tool. The special tool is a cooling system pressure tester. If you don’t already have one you can borrow one from a local auto parts store or purchase one. Here is a good one to have as it will work on multiple vehicles.
Top off the cooling system before installing the pressure tester. Continue to use just water to top off the system for testing. Install the tool and pump the pressure up to the same pressure as the max pressure of the radiator cap. Most are between 15 – 17 psi. Leave the system under pressure for about 30 minutes. If the pressure does not drop then the system has no more leaks. If the pressure has dropped, you will need to locate the small leak. Look for a small stream. Sometimes putting a dry piece of cardboard underneath is helpful to find the area. Repair any leaks found.
Pressure Drops With No Leak Found
You may find that the pressure keeps dropping without seeing any external leaks. If it takes 30 minutes for the pressure to drop just a bit I wouldn’t worry to much about it. However if the pressure drops fairly quick you may have an internal leak. Most internal leaks are from a blown gasket. The most common would be a blown head or intake gasket.
All Leaks Are fixed
Now that all the leaks have been found and repaired there are a few things left to do. I highly recommend replacing the thermostat since the cooling system has already been relieved of its coolant. Coolant is expensive and a thermostat is generally under $20. So take advantage and only buy the coolant once. After you have replaced the thermostat or decided to skip it, the cooling system needs to be properly filled. Drain all of the water left in the system from testing.
Refill the cooling system with a 50/50 mix of coolant. That is 50% water and 50% concentrated coolant. You may also purchase premix if you do not feel like mixing it yourself. Top off the system and bleed as required. For vehicle specific repair procedures get a auto repair manual that can be viewed online.