What is causing overheating?

Steve, there's many causes of overheating. You say you have a new water pump and thermostat, so it's obviously not those at fault.

Just a question ... you say your car is not cooling, but is it actually overheating? A faulty temperature sender unit (it screws into the engine block, usually..) can give an incorrect reading on your gauge.

If it is overheating - steam/you can feel the excess heat - is your radiator fan kicking in? Is your car overheating as soon as you drive it? Or overheating when stuck in traffic .. and the fan isn't kicking in..?

Other things that cause overheating which spring to mind include a blocked radiator and/or a collapsed radiator hose.

Hot coolant enters your radiator via the TOP hose and cools as it goes down the radiator, then back into the engine via the bottom hose. Check both top and bottom hose after the engine has warmed - sometimes a hose can become 'flat' and blocked.

Another thing that causes overheating is a burnt head gasket/cylinder head problem.

Switch the engine on and look at your coolant bottle - a continuous 'bubbling' indicates that exhaust gases are finding their way (via a burnt head gasket) into the cooling system.

Any oil in the coolant bottle also indicates cylinder head problems. Also check the oil dipstick. If coolant (because of a defective head gasket/head) has found its way into the oil system the oil on your dipstick may appear a creamy/greyish sludge.

How are you sure it is overheating? Temp gauge? Most likely are stuck thermostat, bad fan thermostat switch, bad fan. bad head gasket. Coolant going into overflow when hot is how that system is suppose to work. As it cools, fluid is drawn back into radiator. It it is not really overheating, bad radiator cap can allow coolant into reservoir more than normal.

Hi. The contacts in the Coolant bottle get contaminated and then don't pick up the water level. Brige the contacts at the water botlle and start the car, if the coolant/temp light behaves for 5 min or so after starting the car, then change the coolant bottle/resevoir.

If you have the 2.7L engine, you may have a bad water pump. The water pump is turned by the timing chain. When the water pump on those particular engines go out, tension on the chain goes away and retards the camshafts bad enough for it not wanting to start. Pull your oil dipstick out and see if you see signs of water in the oil. If there is, this is your problem. When the water pump goes out on those engines, it'll drain water straight into the front of the oil pan.

I see two possible causes.
1) Something is blocking air from cooling the radiator. Is there any debris like leaves blocking the radiator?
2) Something is preventing coolant from flowing through the engine. Could be a water pump failure.
Make sure your engine old level is within proper range.

most likely a cracked head.

hi there is a lot of causes can make the temperature higher 1- you have to inspect the coolant visually to determine its condition rust.oil(internal engine leak) NB the coolant or antifreeze should be changed at regular intervals .after prolonged use,coolant will break down and become very corrosive 2- a faulty engine fan can cause overheating you have to check water pump if there is any noise coming up it during engine running and check belts and the fan for bent blades ,cracks,flexible fans are especially prone to these problems if any troubles are found replace the fan 3-a stuck thermostat can cause engine overheating if the thermostat is stuck shut,coolant will not circulate through the radiator as a result overheating could make the coolant boil. hope that will help you if you need any more assistant leave it here and i will check it

iam suspecting the temperature gauge here ,something is or could be wrong with its electrical conductivity ,or the cooling fan is coming on too late which could be caused by a similar problem with the fan temperature switch

These vehicles, when equipped with the 3.1L engine are very prone to head gasket failure. A local garage should be able to preform a block check to tell wether combustion gasses are entering the coolant. Because you said the coolant pushed out the overflow this is definately where i would start. The normal operation of that vehicle is for the fans to turn on around 106 degrees celcius. If you can, take a temperature reading of the coolant to ensure they are coming on at the right temp. Other possibilities are an inefficient radiator, coolant temp switch/sensor causing inproper fan on temperature,

The cooloing fan should turn on when the temperature gauge (if so equipped) is just above half way. Under no circumstances should the engine overheat before the fan does come on. The temperature sensor for the computer may not be reading correctly.