Dorman vs. OEM GM coolant "T's"

[Oldmopars]

I got this 2008 2500 a month or so ago and when I got it, it had a leak from one of the coolant T's at the heater core. After some research and several YouTube videos I knew I needed to replace the T's. I ordered some Dorman parts and installed them. To get the old one out, I bent the aluminum tube going to the black T. The slight bend caused it to keep leaking, however I did not know this at first.
I had also read that you should not buy Dorman coolant parts as they "Won't last". So I ordered up some GM OEM parts.
Today I went out and removed the Dorman parts and installed the OEM, I also bent the tube back to the way it is supposed to be.(Small amount of bend, but just enough to cause a leak)
While they were out I took pictures of both parts. With my naked eye I can't see any difference in design, build quality, materials or any other difference. GM is made in Mexico, Dorman is made in China. I'm not sure there is a difference there.
So, look at the pictures and tell me why the Dorman are so inferior to the GM parts. The slight color difference is due to the Dorman one being installed for a month, the GM is new out of the bag. GM has the white "Made in Mexico" sticker.

 

[Geotrash]

The difference is in how well the plastic resins they’re made with, and the internal seals, hold up to the coolant temperatures over time. I replaced my tees in my ‘07 about 18 months ago - one with OEM and one with Dorman because that’s all I could get at the time. The Dorman started leaking 2 months ago. Replaced both of them with billet aluminum tees to solve the problem once and for all.


Sent from my iPhone using Tapatalk

 

[thompsoj22]

I also replaced my 11 yo oem T's with another set of oem T's. I still have the dorman T's in a box in the garage as i hesitated installing them from info on this forum and wanted to wait to compare to oem. The wall thickness is different and the plastic is absolute shit! take your brand new oem T and lay it on the garage floor and hit it with a hammer. Then take a dorman T and lay it on the garage floor and hit it with a hammer and post the results of the test?

 

[adventurenali92]

Plastic Ts for these fittings are trash regardless of OEM or dorman. They’re gonna get brittle after expanding and cooling with the heat from the coolant and then cooling off when the engine shuts down. The best route is to replace with a metal part. Not sure where @Geotrash got his aluminum billet Ts from, but I know that gruven parts makes a kit of parts out of metal specifically to solve this problem and I know it’s a popular company. More expensive I’m sure but worth it to only have to replace the Ts once and be done with it.

 

[Doubeleive]

Dorman revised there "T"'s to make them better than the original version, just throwing that out there, the newer version will always end with "cd" "changed design" what they changed exactly who knows.

 

[Tonyrodz]

Gonna need to get some replacements myself. Mechanic broke mine and replaced with dorman. @Geotrash have a link to those aluminum T's? Are they expensive?

 

[HD_LS]

I got rid to the "Tees" entirely and eliminated this failure point. I don't need the rear heat, and I'm enjoying loads of extra engine room, and easy access to the rear plug & wire. I also don't have to worry about the rear plastic fittings failing either.

I took a length of 3/4 inch heater hose, warmed it up a bit with a heat gun, pre stretched it a little bit, lubed it with anti-freeze and shoved it over the heater core tube (past the raised flange portion). Then put two hose clamps on each one (one before an one after the1 flange portion). Then I put an in-line 3/4 to 5/8 metal hose adapter to get back to the stock hoses. And I cut out the aluminum tubes, in the engine compartment, that go from there to the rear heater core. Works great, eliminated multiple failure points, and gives me much better engine access.

 

[Tonyrodz]

I got rid to the "Tees" entirely and eliminated this failure point. I don't need the rear heat, and I'm enjoying loads of extra engine room, and easy access to the rear plug & wire. I also don't have to worry about the rear plastic fittings failing either.

I took a length of 3/4 inch heater hose, warmed it up a bit with a heat gun, pre stretched it a little bit, lubed it with anti-freeze and shoved it over the heater core tube (past the raised flange portion). Then put two hose clamps on each one (one before an one after the1 flange portion). Then I put an in-line 3/4 to 5/8 metal hose adapter to get back to the stock hoses. And I cut out the aluminum tubes, in the engine compartment, that go from there to the rear heater core. Works great, eliminated multiple failure points, and gives me much better engine access.

Have some pics?

 

[davidavidd]

I do not recommend either of the two, in my city I went to a metal shop where they made me bronze ones, no more coolant leaks since then.

 

[Bill 1960]

Purely from a visual standpoint, a Michelin tire and a Greenball look the same, fit the same wheels. I’m certainly no expert, but I don’t know how to assess a plastic by looking at it.