Your coolant level keeps getting low. At times this causes your car’s temperature gauge to rise above its normal range. When you park, you can detect the scent of coolant outside of your vehicle. It is likely that the culprit is a pinhole leak in a heater hose. You can let the issue go until it causes big problems or you can do some research now and find the leak.With over 5 years experience as a mechanic, here are my recommendations for finding the leak in a heater hose without having to purchase expensive equipment or paying a garage bill.
Heater hoses do not always develop a huge opening.
A pinhole often only leaks significantly when there is high pressure on the hose. Since this generally happens when the car is traveling at highway speeds, the leak may disappear within seconds or minutes of parking the car. Because of this, you will have to work a little bit to find it.
You need pressure in the cooling system to locate pin holes.
Sometimes a bubble will form in the area where the pinhole is located. When the car is cool, you can run your hand along the heater hoses and feel for a spot where the rubber feels stretched and a little loose from the hose. Unfortunately, this does not always happen. To verify that this is the leak, you will still need to heat the car up to create pressure in the cooling system.
Start your car with the heater engaged.
If needed, fill the radiator. Make sure that the radiator cap is on securely. Start your car and turn the heater on a high setting. Doing this will give you two pluses. It will give you proof that the water pump is circulating coolant when the heater begins to blow out hot air. Also, you can be certain that coolant is flowing through the heater hoses.
Either let the car sit and idle or take a short trip.
Since you need your vehicle to be at full operating temperature, the car will have to run for a while. It is a good idea to plan a short trip that will give the car time to warm up. This way, you will not be wasting gasoline.
With the car warm and running, raise the hood.
Once the car has heated up enough that the heater is blowing out hot air, raise the hood with the car running. Be careful when lifting the hood that hot coolant does not spray in your eyes or on your skin. Normally with a pinhole, this is not a great risk, but it can be dangerous. While avoiding getting harmed by the hot engine or moving parts, look for a spray or mist of coolant along both heater hoses.
If no spray of coolant is apparent, look for areas where moisture may be collecting.
Look at the underside of the hood and under the car to see if there is evidence that coolant is present. Use these moist areas to guide you to the spot on the hose where the leak is occurring. If there is a leak, it should be obvious at this point.