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Radiator fittings for tranny fluid lines are wrong size.
I have an ’89 G20 sport van with 5.0. The radiator is shot, a slow leak, no saving it. I bought a Murray 433709 at O’Reillys. It’s the correct unit except for one problem. The female thread on the radiator for the oil lines is 5/8 inch diameter. The old radiator is 1/2 inch diameter. This I discovered after trying to install it. I got the lines in place, but wouldn’t tighten of course. The tension of the fluid line made it difficult to realize it was the wrong size. Then I had the bright idea to take it back out and measure the openings, Just by eyeball with a machinists rule it’s obvious.
I went back to O’Reilly’s, they have no information on the thread size in their computer description of the various models that fit my van. O’Reillys did not have anything on the shelf that looked right.
Last edited by cmac2012; Feb 16, 2023 at 12:34 PM.
Thanks for that, I guess it should have been obvious. Not why I am so insecure with this one. I am half of a plumber myself, I am well-versed in looking for fittings that will make the job work, sorting between flair, compression, and NPT. This one is not common in my experience.
This part sort of looks like a normal flare fitting. Then again, most that I see on the shelf or more of a male flare, this is the female part of the flare. The male part is in the aluminum. Looks like aluminum to brass, I don’t imagine. A really powerful torque is needed to seal. No idea if I should use a torque wrench for that. Maybe the old German way, gutentite is what’s needed.
*ETA* the thread on this almost has to be 1/4 inch NPT. The testing is not perfect, but nothing else even comes close. I’m not finding that inverted flare on the end however. I’m really hoping for the dream fitting, that is, this male part and a female part for half inch to match the male fitting pushing the tranny fluid line in.
But this one I don’t completely understand. Not sure what type of thread is on the bolt like thing that slips over the fluid line. Not even sure how to name that type of thing. But the O-ring inside kinda confuses me. I didn’t think hot tranny oil would be sealed that way.
More *ETA*
The fitting that pushes the fluid line into place doesn’t match any of the three main thread types. Might be 3/8 flare, looks that size, but I couldn’t try it out on the little test rack or with anything off the shelf because the flare tip prevents it from going in far enough. One thing is certain, it’s not pipe thread, it’s not a compression thread. It is a weird sum beetch, that much is clear. I went to a professional plumbing supply store, they said no way do they have it.
Find a fitting that fits the radiator and has an inch or two of line on it. Connect two metal lines with a piece of hose. Throw away the strange fitting..
I've run them this way thousands of miles. In fact I had one Suburban years ago they replaced all of the lines with hose. Worked great until one rubbed a hole on the bracket they'd run them through.
Radiator fittings for tranny fluid lines are wrong size.
