Identifying outgoing trans oil cooler line using K-Type Thermocouple.

[Dauntless]

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

 

[Shaggy]

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

Not sure what you are trying to figure out? Why are you testing the temperatures of the oil lines?

 

[Dauntless]

Thank you for replying. I thought I was fairly clear. I need to know which is the outgoing oil cooler line (trans TO radiator) and which is the return line (radiator to trans). I need to know this for various reasons; e.g. I am installing a magnetic filter on the trans line and it should be put on the outgoing line and MUST face one way - with the flow of the trans oil. I could put it on the return line, again, in the direction of the flow of liquid. Also, I may be adding a trans oil cooler and need to know which way the hoses are flowing. This should make sense.

The outgoing fluid from the Trans is hotter than the return fluid from the radiator (hopefully) so this should be an easy way to find out which is the line going out from the Trans without having to disconnect the hoses, add a length of clear tubing to each hose, end each length of tubing in a bucket of some kind, turn on the engine for 10-15 seconds, and see which bucket starts to fill with trans fluid; that is the outgoing line. But I don't want to be bothered with disconnecting the lines if I can just tell by the other method.

Does the explanation above make sense? If it does NOT make sense, please let me know.

Thank you for commenting.