Temperature/transmission issue

Ok I am trying to work through a promblem with the torque converter not "locking up"

I have a 1998 SL2 with 303,000 Km and I can't always get teh torque converter to "lock up". At first I thought it was the ECT but I had a mechanic check it out and he said it was functioning but the temp was really low and thought it was the thermostat. The thermostat was changed, the car operated hotter and the transmission functioned as expected. This was back in November. In february I hit a pot hole... a large pot hole and caused a fitting out of the rad to leak.. I fixed the leak but the car starting running "cool" again and the transmission wouldn't "lock up". I had the thermostat changed again, now here is where I am baffled, the car operated warmer.. but not quite as hot as it should. The temp gauge reads just a "hair" under the first line and the transmission usually won't "lock up" until it reaches the first line. I bled some air out of the system and that didn't fix the issue. I am going to drain and flush the coolant but if that doens't do the trick I am not sure where to look next. The car will reach the proper temperature if I let it idle for about 20 mins before driving... but once i am on the road the temp drops and often the transmission "unlocks" until the car warmsup again.. on a straight stretch of road I can floor the gas pedal tkae the car to 140 kmph and WATCH the temp gauge drop as the RPM's go up.

Thoughts anyone?

Replace your Engine Coolant Temperture Sensor. Your sotck one is resin an cracks sending false data to the PCM. This sensor is used for transmission shift points, torque converter lock up points, fan operations, along with many other systems. New ones are brass and will last the life of the car.

Normal operating temps for your car is 1-2mm above 1/4 as per the guage.

Replace your Engine Coolant Temperture Sensor. Your sotck one is resin an cracks sending false data to the PCM. This sensor is used for transmission shift points, torque converter lock up points, fan operations, along with many other systems. New ones are brass and will last the life of the car.

Normal operating temps for your car is 1-2mm above 1/4 as per the guage.

So I was going to change the coolant first, but I ran into an issue with the radiator drain plug... it didn't want to leave and if I forced it, it was going to tear (plastic). None of the auto parts dealers in town carry a drain plug for a saturn radiator...including GM.. and the Saturn dealership is 45 minutes away...
So I went I bought an ECTS and a set of pliers that will reach the cap on it. Took me about 15 minutes to change it out. I refilled the coolant the leaked out ( let as much drain as possible, about 1/3 of the total capacity). I started it up let it run for 2-3 minutes and looked for leaks. All was good so I went for a test drive. Less the 1 KM up the road and the car was running great and the torque converter locked up. Five minutes into the drive and the car was running much hotter, more power and the idle was lower (800 rpm instead of 1200rpm)

ECTS $16
Pliers $7
with tax $23 and 15 minutes labour.

I would actually suggest if you haven't changed this part in your Saturn... change it now and avoid a degradation in performance/fuel economy

http://www.youtube.com/watch?v=JC0U53w_Htk

and a video on youtube to show how to it too...:grinyes:

Thanks

Glad you got the car working! The ECTS is always the first suspect for any problem with the car haha.

Also, Richpin has over a hundred videos for different jobs on the s-series. Definetly take a look at them before you do anything to the car as im sure hes done it already :)