High RPM, Low Coolant Temp

Hi!

I have a 1998 SL2 with 165,000 miles. Normally 70mph registers at 3,100 rpm, and my coolant gauge reads about 1/4.

I didn't drive the car for a week, and on the first trip after the week off, 70mph registered about 3,700 rpm, and the coolant temperature was about 1/8. I ran over a bump on the road (about 5 miles from home) and the coolent temp went back to 1/4 and the rpm went back to 3,100. It continued these normal readings the rest of the trip, and the other trips during that day were normal as well.

The next day I drove the car again and the high rpm / low coolant temperature occured again for about 5 miles from home (no bump in the road this time, but stopped at a traffic light). The car then behaved properly the rest of the trip, and the other trips during that day as well.

Any ideas?

Thanks!

How cold is it there? I ask, because this sounds like what normally happens when the engine/tranny is cold. It won't shift into high gear until everything is up to temperature, so that would be why the RPM's are higher. I suspect that the change at the bump was just a coincidence. Just my 2 cents anyway. Good luck, and hope nothings is really wrong.

Could be the thermostat. It seems like your car is not reaching normal operating temperature. This would keep the trans torque convertor from locking up and giving you the higher rpm reading. Not only does the increased rpm effect the gas mileage, but also running cold will cause the car to run rich and use even more gasoline. My Saturn always runs the temp gage to about half way when the thermostat is working properly.

Thanks, it has been warmer lately and hasn't acted as described in my original post. I will keep my eye on it this week as it is supposed to be colder by the end of the week.

Has the ECTS been repalced with a metal tipped version?