overheating at idle, please help.

[eabeathan]

I just purchased a 2003 kia optima, and it now shoots up to red when it idles. I have already checked the hoses to see if it is pressurized. What other problems could I have?

 

[DaTT]

Cooling fan on the radiator, is that running?

 

[NaughtyGeek]

First, is there coolant in the radiator?

If you can drive down the road and the temperature goes to normal then your cooling fan isn't running when it's supposed to. Either the fuse is bad, the motor's bad or the temp sensor is bad.

If you're overheating regardless of driving or at a stop, your cooling system is borked. Either your radiator is clogged or your water pump is shot. Usually if a water pump goes it makes a mess.

 

[LTC8K6]

Yeah, probably the fan is not coming on when it's supposed to.

It could also be a weak water pump, but I'd look at the fan first.

When it's idling, see if the rad fan cycles on and off as it should.

Typically, running the A/C will also trigger the rad fans.

 

[tortillasoup]

If you have the original radiator cap, REPLACE IT!!!! They're supposed to be replaced every 5 years.