Dauntless
Junior Member
There are various ways of figuring out which trans oil cooler line (2008 Cobalt LS - 2.2L. engine/4t-45E Trans) is pumping outwards from trans to the radiator and which is the return line. It would seem one of the simpler methods is to measure the temperature of the metal portion of each oil cooler line and conclude that the hotter line is outgoing and the cooler line is returning from radiator to trans.
I tried this with the engine good and warm and running. I used my digital multimeter and a K-type thermocouple attached to the multimeter. Note that the Multimeter is not a top class Fluke meter but so it is. I put the thermocouple against the top metal line and attempted to secure it with electric tape to get a reading, but this was not as easy as it sounds when bent over the hood and reaching down into a running engine. I could not get the electric tape properly secured but managed to get a reading of 125 degrees to 135 degrees. I don't know if this reading sound accurate or not but I go on. I then held the measuring end of the thermocouple against the metal of the lower oil cooler line and also got a reading of between 125-135 degrees. I went back and forth repeatedly and at no point was I able to get clearly different readings between the two oil cooler lines. I don't know what to conclude from this? I may have a lousy multimeter, a lousy thermocouple, incompetently held the measuring end against each cooling line time and time again, one line after the other, etc. Another possible conclusion is that the journey through the radiator is providing no cooling at all to the transmission fluid passing through. It comes in at 130 degree and leaves at 130 degrees. Maybe 130 degrees is way off and I have screwed up cheap equipment. Can I please have your insight?
Like I said, there are other ways to determine which is the outgoing line (from trans to radiator) but this method should be simple and should give the correct answer. So what do you think is going on?
I thank you. Dauntless
I tried this with the engine good and warm and running. I used my digital multimeter and a K-type thermocouple attached to the multimeter. Note that the Multimeter is not a top class Fluke meter but so it is. I put the thermocouple against the top metal line and attempted to secure it with electric tape to get a reading, but this was not as easy as it sounds when bent over the hood and reaching down into a running engine. I could not get the electric tape properly secured but managed to get a reading of 125 degrees to 135 degrees. I don't know if this reading sound accurate or not but I go on. I then held the measuring end of the thermocouple against the metal of the lower oil cooler line and also got a reading of between 125-135 degrees. I went back and forth repeatedly and at no point was I able to get clearly different readings between the two oil cooler lines. I don't know what to conclude from this? I may have a lousy multimeter, a lousy thermocouple, incompetently held the measuring end against each cooling line time and time again, one line after the other, etc. Another possible conclusion is that the journey through the radiator is providing no cooling at all to the transmission fluid passing through. It comes in at 130 degree and leaves at 130 degrees. Maybe 130 degrees is way off and I have screwed up cheap equipment. Can I please have your insight?
Like I said, there are other ways to determine which is the outgoing line (from trans to radiator) but this method should be simple and should give the correct answer. So what do you think is going on?
I thank you. Dauntless
