2000 Cobra R Overheating

esmith700 said:

I have a 2000 Cobra and it keeps overheating. I have tought that it was the head gasket but if it were the gasket wouldnt it be putting out white smoke? I am not real familiar with the 4.6 or 5.4 engines but would love to get this thing so it is drivable soon. Any thoughts? Thanks.

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Head gaskets do not always show as white smoke out the tail pipe.

There are a lot of things to check before assuming head gasket. I would start by pressure testing the cooling system. If there are any leaks, they should show up. If the system won't hold pressure and there are no external leaks, then you are looking at an internal engine issue such as an intake gasket, a head gasket, or a cracked cylinder head or block.

If the system does hold pressure, I would then start looking towards the thermostat and making sure the radiator cap itself is good. Using an infrared heat gun, I would measure the temperature on the inlet and outlet hoses on the radiator to make sure I have good flow through the radiator. The cooling fans should operate correctly, and the factory air dam should be installed and undamaged.

You also need to make sure that the water pump is circulating the coolant (the blades can actually break off of some pumps causing them to not circulate the coolant) and the system should be properly bled of air.

Lastly, you can have the cooling system tested for the presence of hydrocarbons. The only way they can get into the cooling system is through the introduction of combustion gases, which indicates a blown head gasket or cracked cylinder head.

Can you tell us what the modifications are? Oh, and pictures would be great for the rest of us who don't get to see these very often