Fix for the Transmission Cooling Line
Since this turned out to be part of the transmission cooling system and not engine cooling I took a long shot and swung into a local transmission shop, hoping they wouldn't try to convince me to leave it there for a full transmission overhaul. A quick inspection and he said it was transmission fluid that was leaking around an 0-ring seal between the tubing and the brass fitting. 1st Pic - Be careful not to turn the aluminum fitting directly on the radiator and back out the brass fitting. The plastic retainer can be slid back down the line to expose the retaining clip (Pic 2) I used a home made pick to ease it off on one side and then needle nose to pull it out. Once the clip is removed, slide the brass fitting off the end of the tubing - You'll notice the flare on the end of the tubing, I just used a rag and made sure it was clear of any debris and set the line off to the side. Pic 3 shows the Nitrile O ring set in a groove inside the brass fitting. I used my pick to carefully pop it out and then matched it up with a replacement from an assortment box of O-rings I picked up a while back at HF. I found one that appeared just a bit larger (girth) not diameter and worked it back into the groove in the brass fitting. Be careful Brass is soft metal and easily gouged, I got one end to seat in the groove and then worked around the O-ring with a small flat screwdriver to seat it. I could easily feel the extra girth in the new O-ring when I pushed the brass fitting back onto the tubing. I used needle nose pliers to tighten up the retaining clip before putting it back on, then re-tightened the brass fitting into the aluminum fitting on the radiator, and snapped on the plastic retaining ring. Took about 10 minutes. I got a little residual fluid loss from the line, but let the truck cool down about 30 minutes before starting the job and popped the tranny dip stick to relieve any pressure that might have been on the line.
