1999 Cadillac Seville overheats

1999 CADILLAC SEVILLE
120,000 MILES • V8 • FWD • AUTOMATIC
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DSEW1962
  • MEMBER
  • 1 POST
This car will not overheat while idling but as soon as you put it in drive it starts overheating. Have changed the radiator, thermostat and have done a tuneup. No water in oil. Unhooked catalytic converter to see if it could be clogged. Heat does not work but ac does not sure if this is related.
Jul 5, 2008 at 11:38 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Have it block and pressure tested-do the block first to pinpoint a combustion leaking into the cooling system or a gas analyzer to sniff for hydrocarbons at the radiator fill neck.

Pressure test: do not do a pressure test if there's leakage at the headgasket this might cause coolant into the cylinders and lock it up or bend a connecting rod if cranked thereafter. The headgasket should be repaired before doing the pressure test.

If the block and pressure test passes check the following: Thermostat,Pressure test the Rad. cap,Clogged radiator,Fan clutch,Radiator electrical fan,collaspe hoses,water pump.
Jul 5, 2008 at 4:14 PM
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