Mechanics

98 OVERHEATING

1998 Cadillac Deville • V8 FWD Automatic • 175,000 miles

I have an 98 cadillac deville that over heats I changed radiator, thermostat, radiator cap and its not the water pump. Please help
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Webbiefan
July 6, 2011.




Don't waste anymore time, or money, until you have a block test done for the presence of hydrocarbons in the cooling system. Aside from the occasional thermostat stuck closed, failed W/P belt tensioner/belt, and low coolant level, internal combustion leaks are the major cause for overheat on these engines. The head bolt threads in the block were a poor design from 93 up until about 2004 when the thread pitch was increased.

Factoryjack
Jul 6, 2011.
Thank you for responding now I'm being told its the intake manifold could that be correct

Tiny
Webbiefan
Jul 6, 2011.
Coolant does not flow through the intake manifold, nor would it cause an overheat. There is a passage through the throttle body that can plug and possibly cause an overheat, but it is somewhat rare. If you are not confident in who is giving you the diagnosis, and they have yet to do a block test, I would urge you to demand a test before spending anymore money. If they don't know how to perform the block test, or are not equipped, find someone who is. I would be willing to bet that it has leaking head gaskets(internal) due to pulled head bolt threads.
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Factoryjack
Jul 6, 2011.

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