I HAVE A 99 CADILLAC DEVILLE I RECENTLY HAD A MECHANIC PERFORM A PROCEDURE WITH HEAL A SEAL FOR A HEAD GASKET ISSUE EVERTHING SEEMED TO BE OK THE CHECK ENGINE LIGHT IS STAYING OFF I HAD A CYLINDER MISFIRE, I HAD COOLANT IN THAT #1 CYLINDER CAR STILL RUN SMOTHLY NO MISS BUT IT OVERHEATS WHEN DRIVING IT AN AFTER DRIVING IT THE RADIATOR DOES NOT FEEL HOT IN BETWEEN THE TWO ELECTRIC FANS SHOULD IT BE HOT? ALSO THE MECHANIC THAT WORKED ON MY CAR SAYS THAT HE THINKS IT IS AN AIR POCKET CAN U PLEASE HELP I DONT KNOW WHAT ELSE TO DO THE CAR HAS 107,000 MILES ON IT 4.6L NORTHSTAR
Sounds like that or a bad thermostat I would check the thermostat first. Then after that I would bleed the air system can be done by taking radiator cap off and putting front end of car up about 1-2feet off the groudn and letting the car run. When coolant goes down add more till it wont go down anymore.
October, 29, 2007 AT 10:45 AM
I would say you have a head gasket prob, the threads pull out of the block is actually the prob, its almost impossiable to get a air pocket in a northstar eng
October, 29, 2007 AT 6:06 PM
It sounds to me that you are geting compression through the blown head gasket. Take the coolant cap off, (when it is not hot of course.) Have someone start the car while you look in the tank. You should not get big bubbles. Also put your hand over the hole to check for instant pressure. If yes your getting compression in the cooling system. Could also be a crack in one of the cylinder sleeves.