Originally Posted by elinn
Marked the overflow tank. After a couple of cool cycles the level appears to be the same. I also checked it after a 10 minute or so drive after it got up to temp and the level was the same. That might be normal, I don't know. I let it cool and checked the radiator and it took about a half a quart. This was the first time I cracked the cap on the new radiator so I supposed some air could have worked its way out. If it is low tonight I think I may have a more serious issue.
Now those darn transmission lines are leaking. I had no trouble before with the old radiator, but now the upper line is leaking all over the place. I can't seem to tell if it is the first fitting that is threaded into the cooler input or the actual cooler itself leaking inside the end cap of the radiator. The line connection looks good. I used pipe joint compound on all threads and they are pretty snug. Any ideas? Wonder if I got a bad radiator?
For the automatic transmission coolant fittings going into the radiator, I used the white teflon tape. For the transmission lines going into these fittings, I used plummers thread putty, as I wanted to be sure that nothing could dislodge and make it's way back to the transmission to clog anything.
If one of these are leaking now, this will be the reason you are having to add coolant. As ronD pointed out (as well in a thread I had a few months ago), the leaking connector will draw air into the radiator, rather than it drawing coolant from the overflow. Its a shorter resistance "point of travel".