Cadillac Repair: 2000 cadillac deville overheating problem, key of the proper type, last key used

Question
Cadillac overheated and I replaced the thermostat. Problem arose again soon after so had a hole in radiator and replaced that.  Tension belt tight and purge line flowing freely. Fans are working fine. Could I have a bad water pump still or does this probably point to head gaskets needing replacement?

Answer
Hello,

If you have the ability to have a camp fire, take an aluminum can and throw it is. Watch it melt rather quickly. Your engine is made of aluminum and the graphic would give you the reason that if you are over 225 degrees f, you engine is doing exactly that. You are dealing with Pandora's box here once over heated. Head gaskets are not the cause, but the results of being over heated. It is also the reason you won't find a good junk yard engine. You can bet they have been over heated.

Head gaskets can have one of three symptoms. Coolant in the oil causing it to be a white milky color. Engine runs and white smoke comes from one or both tail pipes, or an obvious leak externally.

Water pumps do break fins off, although rare. I hope you have never put stop leak in this engine. Very small cooling ports. Very common old gasket material left in from changing thermostat or water pump and will lodge in the cooling jackets causing lack of circulation and over heating. Sometimes flushing may dislodge this debris.

I have a love and hate relationship with Cadillac engines since they wee first introduced in 1982. I have owned over 20 Cadillacs and the one fear for anyone that has one of these engines is they cannot be run hot! So many think they can drive the car that extra couple of blocks after the hot light comes on. The engine is literally melting at that time!

I do not know what to tell you. I don't know the extent of damage to your engine, but I guess with your explanation here, I would be checking the head gaskets. I would recommend someone that has a cooling system pressure tester. Check the radiator cap too.

If the system does not hold 15 pounds, you will find your leak .

Good Luck!

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