[nhumston]

04 LS, 4.2 L6 with 360k miles.

Hoping to find some help with the connector on the return side of the radiator. Not because I'm modifying anything, but because it has recently developed a slow leak. Not leaking where it threads in, but where the line snaps into the connector, so pretty sure it's the o-ring.

Either way, needs replaced. Rockauto actually lists two different part #s for the cooler line, radiator side, so tried them both. Part #800-619 (looks a lot like part #15226661, I saw in another discussion)---too small (9/16= ~14mm?). Doesn't even make contact with the threads. Tried the 800-721 (18mm)---too big. Finally hit me to put that connector on a thread-checker. Definitely a 16mm..

Even went as far as trying an old connector, sitting in a 03 LaCrosse radiator I helped a neighbor change about a month ago. Close, but no cigar.

Probably too much info, all to say I'm stumped. Really could use some help/ideas on how to track down the right part.

 

[Vega_TB]

Has anyone replaced your radiator? Is this a genuine OEM part? These connectors are available in two sizes. Here is their description
GM P/N: 15226661 Connector, trans fluid clr pipe (9/16-18) (3/8 body quick connect) (AT RAD) (WITH/BEVELED WASHER)
GM P/N: 52481097 Connector, trans fluid clr pipe (m18 x 1. 5) (WITH/OUT BEVEL WASHER)
Are you sure your version is 16mm?

 

[nhumston]

Appreciate your reply.

Guess I should have mentioned that I did replace my original (guessing---bought in '05 w/30k miles on it) radiator last year....with a non-GM one. Only reason I didn't mention that is because the new radiator did not come with the connectors, had to re-use the ones that were in the original. Perfect fit from one to the other.

Yes, sure about the 16mm. The thread checkers I had access to only went from a 1.0 to a 2.0 pitch, so didn't screw all the way in. Guessing it's still a 1.5, just not 18mm.

Actually tried both of those parts (or the Dorman alternatives), neither one fit. Other than maybe the overall quality, there shouldn't be a difference between the GM and Dorman. That said, and knowing full well that Amazon/Autozone/Advance....whoever, aren't exactly the know all-tell all of car parts, neither one is listed as a fit for an 04:

I'll get some pics this evening.

 

[Vega_TB]

Send me your VIN in a private message. I will try to see what fitting is listed for your VIN (04)