Hi: I have a 1994 Cadillac DeVille: 4.9 Liter V-8 - not NorthStar: Head Gasket blew 11 months ago. At that time I sucessfully applied Dura-Seal which cured my problem. I drove 26,000 miles and now my head gasket blew again. I re-applied head gasket patch. No more leaks however engine overheats while idling. I replaced Radiator, Thermostat, Heater Core, coolant fans run above 195 degrees: Coolant fans turn on and off normally. Now they run almost constantly when driving. Replaced water pump with OEM GM water pump. No change.
Any sugestions? I feel certain that my engine is toasted: some sort of internal damage which I cannot discern. I would like to get a few more miles out of it though. I just cannot keep the engine below 220 F when the outside air temp goes above 75 degrees. If I take thermostat out car runs cooler, still runs at 210 F when outside temp is above 75 degrees.
When car is cool; car runs 100%. Good gas mileage till temp outside goes above 75.
I doubted my temp guage so I installed an aftermarket temp guage which shows an even worse overheat condition. I cannot keep driving at 235 F, must solve problem.
Checked New radiator for cool spots; None found.
Engine Rebuild costs more then car is worth. Any suggestions, please contact.
Thanks!
Any sugestions? I feel certain that my engine is toasted: some sort of internal damage which I cannot discern. I would like to get a few more miles out of it though. I just cannot keep the engine below 220 F when the outside air temp goes above 75 degrees. If I take thermostat out car runs cooler, still runs at 210 F when outside temp is above 75 degrees.
When car is cool; car runs 100%. Good gas mileage till temp outside goes above 75.
I doubted my temp guage so I installed an aftermarket temp guage which shows an even worse overheat condition. I cannot keep driving at 235 F, must solve problem.
Checked New radiator for cool spots; None found.
Engine Rebuild costs more then car is worth. Any suggestions, please contact.
Thanks!