Why is my car overheating?

(2010-05-29 16:40:46)

1. candy Says: I have an overheating problem with my 98 honda civic. I've already replaced the radiator and thermostat yet my car takes a lot of coolant. here are some symptoms:

- temperature gauge goes to H, but when I turn on the heat it goes back to normal within minutes
- no white smoke is coming out of the exhaust
- no milky substance inside oil cap

Please help, Ive been having this problem for awhile.

2. Mikaela P Says: Check for coolant leaks. Possible areas are water pump, radiator hoses, head gaskets(internal). Check also your fan if they are working properly. Hope this help!

3. Silverstang Says: The cooling fan on the radiator is not working.

4. Evan Says: You have a leak some where, coolant doesn't vanish, it stays in the engine and recycles.

5. StephenWeinstein Says: Loss of coolant is normal in a 1998 Honda Civic, due to evaporation.

The best option may be to simply keep the heat on all the time.

Some rather obvious things to check are:

a. The coolant pump (which is sometimes called the radiator pump, but is not part of the radiator)
b. The hoses (a clogged hose would do this, and 12-year-old hoses are old enough to replace even if they seem fine)
c. Wrong ratio of coolant to water

6. helpful bob Says: Start off with making sure that the rad, rad hoses, engine, cooling system has no leaks.Next check via a owners manual, or service manual or dealership regarding if the anti-freeze that you're using is within the proper factory recommended specs and the right recommended coolant is in fact being used.

Most vehicles are okay with going by a 50/50 anti-freeze-distilled water mixture or mixed for a good -40c, sometimes due to extreme temperatures the mixture might be 60/40 but never more then that.With the engine cold and not running check and test the quality and mixture of the coolant.

Next try starting the engine and squeezing the thermostat house to be sure that once the engine is warming up that the thermostat is working but since you mention that you've heat then more then likely the thermostat is working but the thermostat might not be the proper temperature rated via factory specs and that could cause the engine to run hot.

You could have an air bubble or air clog in the coolant system some vehicles have a bleeder valve by the thermostat or coolant system and that can be open once the engine warms up and once you see only coolant coming out the air should be out of the system but sometimes you need to bleed the system a few times yin order for it to be fully bleed of any air.Another way to bleed the air is start up the engine cold remove the rad cap or over flow reservoir cap and watch the temperature gauge and stand back bec the coolant will end up gushing out and forcing out the air at the same time.

Another thing you want to do is when you're testing the thermostat etc watch and listen for the fan or fans to engage bec it should engage once the engine is warmed up and sitting idling for awhile, also try turning the A/C on once the engine warms up and sits awhile bec a fan should engage when the A/C on etc.

If the fans aren't working check the thermostat temperature sensor or engine coolant sensor, also the fan fuses,fan relays, fans, wiring, and any related fan control modules etc.

Another test is try driving the vehicle on the hwy for a bit but make sure you've extra coolant and that the coolant level is correct and if it doesn't over heat at hwy speeds that tell you that the water pump is probably okay and that the engine block doesn't more then likely have any cracks etc.It also suggest that the thermostat must be working and that either the fan or fan control system such as the fan, fan relays or fuses or a sensor, wiring might be faulty.Note that the only way to properly check for any blocks cracks is via a special x-ray machine and it costs about 100 bucks or so to get done.

Hope that helps and best of luck.By the way don't forget to double check all the rad hoses any hose clamps etc.Sometimes you can tell if a water pump is faulty via checking it's pulley if it's wobbling or leaking at it's base all are signs the the water pump could be faulty and causing your over heating problems,remember that the water pump has internal blades that could be damaged or broken and a loose water pump belt can cause such issues too.