Overheating, New Radiator, Cylinder Head Gasket

Hi. We have a 2003 Kia Spectra. The car overheated a number of times since we bought it used. This 3rd week of Dec 2007, a new radiator was put. This done because the little cap or lid where you drain the coolant/water was found broken; the topmost of the old radiator shows really bad wear from overheating a number of times. Yesterday, the car overheated again despite having a new radiator. An old man who is our friend and a good mechanic told us over the phone that when the car is cool, open the hood, remove the radiator cap, and another person has to turn on the engine. When the coolant/water from the radiator sprinkles (like a fountain), the problem lies in the cylinder head gasket. We have to take it to the mechanic immediately. The friend/mechanic said that the cylinder head gasket must have been burned by now since the car overheated a number of times.

Is this a costly repair? Around how much?
When we replace the cylinder head gasket, will this be the end of overheating?
I read a water pump may need to be changed (in one post here I read that was answered), will that also apply to us?

In relation to the car's problems, this Kia Spectra is still shaking a bit every other time you turn on the engine. Three days ago, it shook badly. We have changed the spark plugs, 1 ignition coil, ignition wires. Please note that there was one stuck spark plug on the passenger side. The first time we had the spark plugs changed because it was misfiring according to one shop, they only had the 3 changed. So, in the 3rd week of Dec 2007, we were able to remove the stuck spark plug and all spark plugs were changed. However, the thread where the stuck spark plug is located may have been damaged a bit since there is more twisting of the spark plug needed when we put it back as compared to the other spark plugs. We suspected that an impact driver was used instead to put this particular spark plug when it should not be.

Why is the car still shaking even a bit every other time you turn on the engine? Is a tire balance needed? All tires are relatively new.

Why did it shake so badly? (All fluids have been changed in the 3rd week of December. When it shook badly in the 4th week of Dec 07, we took it to the dealership and the diagnosis was random multiple misfiring and the spark plugs we put are wrong. Only particular Kia spark plugs must be put.)

Many thanks for your time. There are many aftermarket sparkplugs that are designed for your car. The trick is to gap the plugs properly prior to installation. One plug might fit six engines with different gaps. Someone might of dropped the plug. So you always check gap.
Possibly one of your coils are bad.

Head gasket.... I would run a compression check. It will tell you if the head gasket is bad if there isn't other obvious signs. If one leaks from a cylinder to a coolant passage, the radiator can boil like your mechanic mentioned. Coolant can also get into your oil pan. Check the dipstick and see if is a chocoate milk color or moisture on the dipstick.

Turn the AC on and the electric cooling fan under the hood should come on. Make sure it's working.

Water pump....feel the upper radiator hose, it should be cool and when the car gets up to temperature the thermostat will open and that hose will get hot. You know you thermostat is working then and a good sign the water pump is too. Squeeze the hose then and let go, you'll feel the coolant surge, then your sure the water pump is working.

If your car shakes idling, then the tires are not the problem.

Head gasket repairs can be expensive. $600+ depending on whether the head needs machined or not. A gasket set alone is around $150. Grease Monkey,

Thanks for the response. I really appreciate it. I will be back anytime sooner to update. The needle goes to HOT when at a stop light, is that overheating? We went to Auto Zone today.

Do you think the tread of the cylinder (??) where the stuck spark plug used to be may be the cause of vibrating/shaking? We had tire balance and alignment last Saturday as told by my brother but you said, vibrating/shaking is not related to the tires? It shakes a bit when you start the car.

Thank you. If the tire was out of balance, it would shake only when driving down the road.

Yes Hot, it's on the verge of overheating. Have the mechanic check it out. Could be as simple as a stuck thermostat. How is your heater working? If you had a hard time screwing the plug back in you might be leery of taking it back out because it is probably crossed. Like they say, "New threads are better than old". You can perform a cylinder block test to see if your head gasket is allow combustion gases into the coolant system.Car Repair Talk's forum.