2001 chevy Blazer radiator trans coolant lines

Are there o rings in the line connections to the radiator of a 01 Blazer. I replaced the radiator a couple of months ago and noticed a trans oil leak the other day. Before I could fix it the line blew out today and when I looked inside there is no o ring. I pulled the top line and there is no o ring. I do not remember there being o rings when I installed it. I read a note that there are no o rings on the trans coolant lines. Anyone know for sure, because my auto parts supplier couldn’t tell me for sure.

Thanks Dan

I think yes but cant say for sure.I do know that those lines can be trouble to deal with (hard to get out,then not sure their in fully even with the clip on)

On these things, the transmission cooler lines don’t use o-rings, but the engine oil cooler lines (if equipped) do use them. I’ve replaced a few radiators in multiple Chevy trucks, and this was the case every time.

It’s tricky to get the trans cooler lines seated just right. At least once I’d have everything bolted back together and start it up, and sure enough one of the trans cooler fittings would start bleeding at the radiator. Loosen it, make sure it’s seated good and re-tighten. I learned to make a mental note of how deep into the threard the fitting screwed, so that if it didn’t go that far when reassembling everything I’d know to remove it and try again.

I replaced the radiator on my 2000 Blazer 3 weeks ago. There are internal o-rings on both the oil cooler and transmission line fittings. I’ll check the old fittings to make sure, I’ll post back if I’m incorrect. The new radiator came with new transmission line fittings already installed. I had to purchase the oil cooler fittings separately. I did not reuse the old fittings.

I checked the old fittings when I got home from work. Both fittings have an internal o-ring. The trans fitting (small) does not have an external o-ring. The oil cooler fitting has an external o-ring where it screws into the radiator.

Correction to oil cooler part #
The Dorman/Motormite Part # for the trans fitting is 800-605. I checked the receipt, the part # for the oil cooler fitting was 800-607. It would be best to bring the old fittings if you’re going to get new ones.

I installed the fittings on the radiator first. Once the radiator was in place, I connected the trans and oil cooler lines by inserting them into the fittings until they clicked into place. No leaks so far, but I will keep an eye on it.

Good luck,

Ed B.

thank you OldSchool

Thanks Edb,I don’t have the old radiator anymore but I did purchase some o rings to try and install. I purchased the cheap plastic tool to remove the snap rings and it broke, that’s what I get for trying to save money. I will purchase a steel tool and try removing the line and installing an o ring. It’s down to a slow drip right now.
The radiator I purchased had all the fittings connected but there were no o rings on the trans side. thanks for the feedback I’ll let you know what happens. Dan

I was able to remove the clips with needle nose pliers. After the clips were removed I unscrewed the fittings, then removed the lines from the fittings. I wrapped the new fittings with teflon tape before installation.

Are the fittings leaking at the threads or where the lines goes into the fittings? Are you attempting to replace an internal o-ring or the external ring on the trans cooler fitting (small fitting)? On a job this labor intensive I would just replace all the fittings.

Good luck,

Ed B.