Q&A for How to Diagnose a Cooling System Problem

To invert the car cooling system, you can begin by running the vehicle with the heater set to the highest level. This action facilitates the movement of the coolant within the system. Eventually, as all the air is expelled from the cooling system, the coolant will release with a forceful spurt from the top of the radiator, resembling a small geyser. Be prepared for some spillage during this process.

Try doing a pressure test to ensure there is no leak in your coolant system. Assuming there isn't, your water pump has likely gone bad.

There's either not enough coolant going around to handle all the heat that your engine is producing, or you may have a leak under the hood.

If your thermostat gauge fails to work, it may be the result of a faulty coolant temperature sensor. Refer to your specific vehicle's service manual to locate and replace the sensor.

Get off the road ASAP before you fry your engine. By the time you're burning coolant, it's already gotten pretty bad. Either your engine is running so hot that the coolant is burning inside the system (which would be a rare sight, and would require some serious attention), or you have a leak under the hood which is spilling coolant onto burning hot engine parts. No matter what, when your coolant is burning, your entire motor is soon to follow.

If your coolant system is not producing enough pressure to open your thermostat, it is likely caused by a kink in a coolant line, a leak, or a fault water pump. Visually inspect all of your lines and your radiator for signs of leaking or kinks. If you don't find any, you may need to replace the water pump.

It's either a blocked overflow pipe or a defective radiator cap. If water is flowing into the expansion container but not out back to the radiator, then that's going to be a faulty rad cap - replace it.

You may need to drain and flush your coolant. Over time, the coolant's ability to dissipate heat becomes compromised. Under normal driving conditions it may be getting the job done, but when the engine is under abnormal stress due to the ambient heat or increased work load it may not be able to keep up.

Check the water pump as it's responsible for making the coolant/water go around the engine block.

This may be an issue with your water pump. Because it is a belt driven accessory, the pulley can fail, causing it to not get enough or consistent power from the engine.

Your radiator fan may not be turning on due to a blown fuse, an issue with the wiring, or a failed coolant temperature sensor. Start by checking for the fuse, then use a test light to ensure power is reaching the wiring for the fan. If those don't solve the problem, try replacing the coolant temperature sensor.

The most obvious sign is the radiator fan. A) If your temperature gauge goes past half-way, and your rad fan doesn't turn on, that means the thermostat isn't opening up like it should when the engine reaches a certain temp. B) If your rad fan turns on the moment you start your car, that means the thermostat isn't closing. A is an overheated engine waiting to happen. B is not harmful to the engine, but your fan motor will eventually wear out sooner than it should.

Removing the lower radiator hose will drain most of your coolant from the radiator and engine. It's located at the very bottom of your radiator; it's quite large in size (often larger than the upper rad hose). Try getting a large drip pan underneath because it tends to spray out a few feet at first. Alternatively, don't fully remove the hose from one end. Just sort of crack it open and get a bucket in the approximate location where you think it's going to pour. Always wear protective equipment and ensure that the vehicle had sufficient time to cool off.

In your fuse panel, check for a fuse for cooling fan. Make sure it's not burnt out. If it is, replace it. If it's not burnt out, check your wiring to your cooling fans and make sure they're plugged in (with the vehicle off and not running.) Spin the fan by hand to see if it turns. If it is hard to turn, your fan motor is probably burnt out and needs to be replaced.

If you don't see any bubbles, your a/c system should be fully charged. Do not put anymore Freon in, or your a/c would be over charged.

That might be a gas leak. Do NOT drive it under any circumstances until you have a mechanic take a look.