[West Coast GTO]

My new-to-me 71 GTO has an aftermarket trans cooler installed via rubber lines. I wish to go back to the original metal cooler lines but the radiator piping connections have been open for quite some time.
Is there a way that I can test and or clean the lines without removing the radiator and having it rodded and repaired?
Thanks in advance.

[Goatracer1]

Try compressed air and look for bubbles in the coolant.

[West Coast GTO]

Thank you, that is a great idea.

[pfilean]

If you use compressed air and get bubbles in the coolant you should have had coolant leaking out the transmission tube fittings before. Or else you used too much pressure and created a problem you didn't have before. Remember the radiator may have only been designed for a 15lb pressure cap. Can't say what pressure the transmission may have been putting in the cooling line. Start easy.

[West Coast GTO]

Another great point. I assume that, if no air bubbles in coolant, then no leaks. No leaks, then what could be used to clean those cooler lines from any possible accumulated dirt/ debris?

[Goatracer1]

When you have a leaking cooler the fluid leaks into the radiator not the other way around. The cooler will withstand much more than 16psig. If you have coolant leaking into the transmission then the cooler has blown apart and chances are the trans has stopped working from a loss of fluid into the cooling system. To look for a leak keep the pressure at a reasonable amount. You don't need much. Good luck.

[Squidward]

Originally Posted by West Coast GTO

Another great point. I assume that, if no air bubbles in coolant, then no leaks. No leaks, then what could be used to clean those cooler lines from any possible accumulated dirt/ debris?

Squirt mineral spirits into it, then blow thru with compressed air. If you want to get real tricky, try a pressurized solvent flush system. I got one similar to this for doing AC work, and it works perfect on tranny coolers too. A few 100psi shots of flushing agent cleaned out the cooler in my truck after the 4L60E ate itself. So much metal...

A flush kit should be available at a local auto parts house. I got mine at a Carquest.

Tranny oil working pressures are up in the 100-200 psi range, so tranny fluid will definitely find its way OUT of the cooler and into the coolant with the tranny in operation. It could flow the other way, tho, after the engine is shut off and pressure remains in the coolant while the tranny fluid reverts to atmospheric pressure.

[West Coast GTO]

O.K., Napa for a flush kit makes sense.

Originally Posted by Squidward

Squirt mineral spirits into it, then blow thru with compressed air. If you want to get real tricky, try a pressurized solvent flush system. I got one similar to this for doing AC work, and it works perfect on tranny coolers too. A few 100psi shots of flushing agent cleaned out the cooler in my truck after the 4L60E ate itself. So much metal...

A flush kit should be available at a local auto parts house. I got mine at a Carquest.

Tranny oil working pressures are up in the 100-200 psi range, so tranny fluid will definitely find its way OUT of the cooler and into the coolant with the tranny in operation. It could flow the other way, tho, after the engine is shut off and pressure remains in the coolant while the tranny fluid reverts to atmospheric pressure.