My car is overheating, especially when idling. It water gets so hot it boils. What could be the problem?

Question

My car has been overheating for months. I have used the proper mixture of antifreeze and water. I have had to tighten the clamps on the upper hose because it swells so big some times, one time it completely came off. The other day the car wouldn't start. I took it to a mechanic and got it back yesterday. He said there was something wrong with some wiring, and the reason it had been overheating was because of a bad radiator cap, and he replaced it. I drove the car this morning and it was overheating so badly it took me two hours to get it back to the house. And it looked like smoke was coming from the engine, around the spark plugs. But I don't know if the smoke was from water being sprayed on the engine or if it was actual smoke coming from inside the engine. The engine ran fine until the car started to overheat, then it sounded really rough and no matter how far I pushed down the gas, it wouldn't hardly move. Also, the front window got foggy, and I tried the air, it was hot. HELP!

Answer 1

Running the heat on the inside of your car can help cool the engine off when necessary.

Answer 2

You did'nt give us the year, make or model of your car so the following are general things to be aware of when trouble shooting cooling systems:

I'd have the cooling system pressure checked to see if you have internal or external antifreeze leaks. It's a simple inexpensive procedure that will do away with a lot of guess work on any mechanic's work.

A pressure check works like this: A mechanic removes your radiator cap and places another testing cap that's connected to a device that looks like a small bicycle air pump. The mechanic will pump positive air pressure directly in your cooling system. On the pump you will notice a pressure gage that will monitor the air pressure that's just been pumped in your cooling system. Ideally this initial pressure will stay the same for hours.
If the pressure bleeds off quickly he'll be able to pinpoint any internal or external leak and make necessary repairs. We would be "shooting from the hip" if we listed probable causes of the overheating problem because the list would be long.

The radiator core partially plugged or leaking. The O rings around the expansion tanks may be leaking. One of the plastic expansion tanks may have a crack. The heater core may be leaking. The water pump impeller may have broken or the pump itself. Antifreeze may be leaking through the weep hole on the waterpump. The electric fan motor or switching mechanism may not be working. The thermostat may be sticking in the closed position. the lower radiator hose may have collapsed.
Worst case scenario the head gaskets bay be leaking or completely blown between the cylinders. If your motor is a V-6 or V-8 the water crossover passage may be leaking coolant inside the motor.

Answer 3

First of all, what make/model is the car? It sounds like a stuck thermostat, but it's hard to be sure without looking at the vehicle. The water pump draws water from the lower radiator hose, circulates it through the engine, then returns it through the upper hose, through the thermostat, and back into the radiator. I would start by replacing the thermostat, as they are inexpensive ($5-$20) and easy to install. Also, autozone loans out tools, borrow a coolant pressure tester, and follow its instructions to make sure your system isn't losing pressure somewhere, as this will cause the coolant to boil (which is why the radiator cap will cause this, as it is supposed to hold 15psi of pressure). If you get the thermostat in, and pressure test comes out okay, then you should be in business as long as water pump is okay and radiator is not clogged. Hope this helps, good luck

Answer 4

It sounds like the engine has overheated to the extent that the heads have warped and a head gasket has blown. Your problem most likely originated with a water pump leak or a sticking thermostat. The window fog is most likely from excessive pressure causing a leak in the heater core. Take the car to a reliable technician to determine the extent of the damage and the cause.

Answer 5

The cooling system of an automotive engine is pressurized so to avoid the water boiling too quickly. The water inside the system will never boil if the system is working properly.

If you say the water in your engine boils, it´s more likely due to a leak in the system leading to a pressure loss. THis leak can be caused by a weak or cracked hose, faulty cap, radiator leak, etc. Tell your mecahnic to look carefully and trace the whole system slowly for any leaks.

The leak doesn´t necessarily have to be a running leak, just a few drops can depressurize the system allowing the water to boil quickly.

Hope it works...let me know

Answer 6

On the overheating, it might be either the thermostat might be faulty or the water pump. Now, if the thermostat didn't open and there is a rush of cold water going to the thermostat, that could be the cause of your water leakage. As far as the windoiw fogging up, it most likely is the heater core in your car is faulty and needs to be replaced. It is located inside the dash. If you have anymore problems, email me back

Answer 7

Did you take an air hose and blow out the radiator fins? If they become full or clogged with dirt that would cause your car to be a little hot at idle because the fan cant push the air through the clogged fins. Just a thought.

Answer 8

I had the same problem last month and all it was a $8.00 thermosstat replacement