Jeep is running hot
The first thing, of course is to check your coolant level, and if coolant is required, to add it in the proper proportion with water that is recommended for your climate. Now remember, if you need to add a good bit of coolant, you probably have some sort of leak, and will need to determine where that is and stop it
If it overheats only when sitting it is likely to be an electric cooling fan motor or the thermo switch that turns the fan on and off that is not functioning. Sometimes the fix for this can be as simple as checking to see that the wires are properly connected for both.
If they are, then stand next to the car when you start it up and, after the car has warmed up, listen to see if the fan comes on. After awhile it should cycle on and off to help cool the car. Enough air passes through the radiator when you are on the highway that the fan is not needed, and so the car will not overheat then even if the fan or thermo switch is bad.
if it overheats all of the time, and your coolant is both full and the proper mixture, then you can look to a few other causes: a clogged radiator, a bad water pump, a bad thermostat, or in the worst of all worlds a blown head gasket or the like
let us take the waterpump first. It is a relatively simple propeller like device inside a housing and as it is turned by the belt if pumps the coolant. When it fails, typically what happens is the seal on the pump fails and coolant begins to escape past the bearings on the pump and out a drain hole built into most pump housings and you will see evidence of the failure in coolant pouring out below the pump area.
If that is not the case, let us look next to the thermostat. For the most part thermostats when they fail, fail in the open position--that is, they allow the coolant to circulate freely between the engine and the radiator without a mind toward whether the engine is operating at precisely the optimum temperature or not. So in most overheating situations, the only way a thermostat failure can be the culprit is if it failed in a partly or entirely closed position--thereby limiting or stopping the flow of coolant entirely. If it failed closed the car would overheat in just minutes. Partly open failures, not common but possible, would impede the flow and limit cooling capacity. You might see evidence of it on very warm days only, or climbing hills, or pulling trailers--that sort of thing. An easy way to determine if the thermostat is working properly is this: When you first start the car in the morning, sit for several minutes and watch the temperature guage carefully. It should slowly rise as the temperature in the coolant in the engine increases. Then at some point it should suddenly drop back a bit signalling that the coolant in the engine has reached operating temperature and the thermostat has opened to exchange the coolant with the cooler fluid still in the radiator. If is does, the thermostat is still functioning.
Now, assuming that the thermostat is working and the waterpump is working we need to look at the radiator. If you do not change your coolant often, the inside of the radiator can become coated with sludge from corrosion (the coolant has a corrosion inhibitor in it that goes bad with age). That sludge can serve as an insulator to limit the radiator's capacity to exchange heat. If that is the case here, you will need to use a radiator flush to dissolve the goop and then refill with the proper mix of coolant and water suitable to your climate area.
Have a nice day..
Aug 03, 2010 |
2001 Jeep Grand Cherokee