we have a 2000 deville with 92,000 miles took it to the dealer
because it started to overheat they change coolant and put in new thermostat
still overheating . no coolant in oil no leak ????????????? thanks for any info

 

car

 

we need more info .....


https://www.cadillacforum.com/m_9792/tm.htm

 

My 2000 Deville was overheating too. Here's how I fixed it. First, here are the symptoms I noticed. It would drive fine and then over heat. I'd let it cool off never driving with the temp gauge in the red to limp home. One night it was driving fine and then boom. On the freeway it stopped blowing hot defrost air and the needle started to creep up. I let it cool, drive as far as I could, let it cool, drive more to get home, then I hit a big pot hole and bam... the defrost started to blow hot air and the temp gauge went down. Got home and parked it. Replaced the thermostat. Still over heated. Replaced the water pump. and while replacing the water pump we blew all the coolant lines with the air compressor and flushed them out. While doing this we were blowing air into the return line to the coolant reservoir and felt a little resistance with the air then a pop at the end of the line. Clearly the return line had been clogged and once that line was open everything worked fine again. In retrospect I didn't need to replace the thermostat (although when I did the rubber gasket looked rippled) or the water pump.It was the clogged return line. Hope this helps. By the way, I'm a 60 year old woman and did this myself with youtube videos.

 

Hi, I’ve a 2000 deville base. It's overheating! No leaks, not losing any coolant, no white smoke, no milky substance in the oil. What could this be to overcome it?

 

I'm having the same problem. Water level drops slowly, then overheats. Can't find a leak, no water in oil. Changed thermostat and checked the small tube(it was clear). Also having a misfire in cylider two. Changed the plug, was good for a while, now missing again. Could the two be related?
2005 DeVille

 

First thing I would do is rent a head gasket tool from autozone. You'll have to pay around $5 for the fluid. Just follow the instructions and use it on the coolant overflow reservoir. You want to first rule out head gasket failure because otherwise you'll be doing major engine damage driving.