ok last night my wife is driving her 2001 sunfire 2.1 L home and the temp guage was going to max, then min, then max then min. she pulled off on an off ramp, the car died, then would not start again. she had an oil change done on saturday, but did not have any coolant fluids touched. the serpentine belt is on and good.
its at a tuffy's shop now, and we are waiting on them to call us.
does anyone think we could have done any damage, or what could have gone wrong? keep in mind, its only got 52,000 miles on it, and up until the drive home, she had ZERO issues with the car at all. Im hoping this doesnt turn into a repair bill of thousands of dollars, or a junked engine...

not sure but when i had a problem like that with my temp gauge, mine was just a broken wire going to the ect sensor. my car never died though so i dont know.

im hoping we didnt do damage..

Sounds like an electrical issue - not a mechanical one. She would have seen steam with the car off if it had overheated. It also can't cool and heat THAT fast, so I wouldn't worry about the motor being cooked. The gage would never go down to MIN after it's been running hot - maybe down to normal, but not likely any lower.
I believe that the BCM feeds the cluster with its info, and the BCM gets its info for that from the PCM. I would guess that maybe the PCM was spitting out info intermittently, and then shut down entirely. I don't think that this is a common failure any more, but at least there should be enough used units around to get things going without too much expense. It will probably cost more to get it properly programmed than to find another module.
Hopefully these are pretty smart guys you have taken it to. Problems like this can get time consuming very easily if you're not 100% familiar with how all of the parts interact.
Good luck!
John

what about it being a head gasket???

Were there any signs of something unusual happening other than the strange behavior of the temp gage prior to it shutting down? You would have noticeable coolant loss and steam if it was the gasket. These are not a typical problem on models newer than 1997.
If the coolant level is fine, then I would suspect that it was an electrical malfunction - not a mechanical one. The gage isn't hard-wired to a sensor like the older cars. The sensor feeds the info to the PCM (powertrain control module - under the hood), which provides certain information to the BCM (body control module - inside the car). The BCM provides serial data to the gage cluster telling it what to display. It could be anything from a cluster issue, to the BCM, PCM, temp sensor, or wiring. The fact that the car shut down would lead me to believe that it's something more serious with the PCM, as that is the main module that operates all of the engine's required electronics.
I assume that you meant 2.2L - not 2.1. There was the 2.2 and 2.4 sold in 2001 - no 2.1's. The 2.2 is the most common, unless it's a GT coupe.
John

its not a GT. it was so dark where she broke down i coudlnt see anything until the tow got there.

There is always a chance that the alternator decided to go out..... when your voltage drops enough to where the car won't run... the gauges like to jump around like that...


Did she try restarting the car or notice any lights dimming?

no she did not notice that.. just that temp gauge, and "check gagues" light.. but not a check engine light