The SL first arrived along with the introduction of the Saturn lineup in 1991. Dex-Cool coolant and water keeps the 1993 Saturn SL1's 1.9-liter engine within a safe operating temperature. When the SL1 starts leaking coolant, it is important to address it immediately. Failure to address it quickly can lead to the engine overheating and causing severe damage to the engine.
Visual Inspection
The Saturn SL1 has five main areas that you can visually inspect for a coolant leak without tools. Allow the engine to cool prior to performing this inspection. Run your hand around the upper and lower radiator hoses. Feel for any splits or cracks in these hoses. Check for any dried coolant on the radiator, particularly the joints connecting the outer plastic tanks to the metal radiator core. Check the coolant overflow tank for any cracks or breaks. Check the floorboard of the SL1 for any dampness, as a leaking heater core will cause coolant to leak onto the floor. General Motors also released a technical service bulletin stating that you may see small leaks from where the radiator hoses connect to the radiator. If you notice this leak, replace the radiator hose clamps and recheck.
Pressure Test
Sometimes a leak only occurs in the 1999 Saturn SL1's cooling system when the system is under pressure. You do not want to check the system while it's hot. A pressure test kit creates the 18 psi that the cooling system creates. Once the pressure is at 18 psi, you can check for leaks in the same areas as listed in the section titled "Visual Inspection," as well the mating point between the cylinder head and the engine, the thermostat housing and the engine block.
Using UV Dye
When a hidden or extremely slow leak occurs in the 1993 Saturn's cooling system, you must use a ultraviolet dye to find the leak. Fill the cooling system with 50-50 premixed Dex-Cool coolant and add in a Dex-Cool compatible UV dye. Drive the car, or let it run, until the coolant level drops. After it drops, use a black light and UV sensitive glasses to scan the entire engine compartment for remnants of the dye. This helps you identify where the source of the leak is.
Quick Fixes
If your 1993 SL1 is leaking coolant from a radiator hose, you can repair the hose on the side of the road. Many department stores sell radiator hose tape, which is a heat-activate tape that temporarily seals the hose until you can get to a repair facility. Also, purchase a male-to-male hose connector and two hose clamps to cut the hose at the broken point and attach the two halves of the hose with the connector. To make either of these quick fixes possible, always keep 2-gallons of 50-50 premixed Dex-Cool coolant in your SL1's trunk -- the 1993 SL1 has a coolant capacity of 1-3/4 gallons.
