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.

 

[Geotrash]

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?

Here you go, @Tonyrodz. Gruven Parts. Not cheap, but good peace of mind. I have them on both of my Denali's now.
https://www.gruvenparts.com/billet-gm-heater-core-coolant-tees/

Also, Dorman makes a coolant pipe assembly for the water pump end that uses a metal tee. It's a great part so I used it in both of my trucks also when I did the job:
https://www.ebay.com/itm/HVAC-Heater-Hose-Assembly-Dorman-626-553/113134563530

 

[gooffeyguy]

I changed out the OE ones on my 2001 for good measure a couple years ago when I did a heater core back flush. They had about 200k miles on them, weren't cracked or leaking and just looked a liitle faded in color. I replaced them with the same GM parts.

To tell you the truth, I never new these were a problem until I started reading on here a few years ago that they are such a problem! I mean, it's not like I see all these tahoes, yukons, and suburbans broke down on the side of the road everywhere I look, lol.

The aluminum Gruven parts look nice, but are very pricey and use rubber hose and clamps to connect, which right there makes more failure points if you ask me.

Now, if someone were to make metal ones that integrated the factory style quick connect system......win

Sent from my SM-G930V using Tapatalk

 

[HD_LS]

Have some pics?

Here are the Tee elimination pics. The first one shows the 3/4 to 5/8 metal hose adapter connections. The second one shows the 3/4 inch hose connections to the heater core. One clamp on each side of the flange bulge of the aluminum heater core tubing. This ensures that it will both seal, and can never pull off. Regular worm gear screw clamps would work just as well.

 

[Oldmopars]

I changed out the OE ones on my 2001 for good measure a couple years ago when I did a heater core back flush. They had about 200k miles on them, weren't cracked or leaking and just looked a liitle faded in color. I replaced them with the same GM parts.

To tell you the truth, I never new these were a problem until I started reading on here a few years ago that they are such a problem! I mean, it's not like I see all these tahoes, yukons, and suburbans broke down on the side of the road everywhere I look, lol.

The aluminum Gruven parts look nice, but are very pricey and use rubber hose and clamps to connect, which right there makes more failure points if you ask me.

Now, if someone were to make metal ones that integrated the factory style quick connect system......win

Sent from my SM-G930V using Tapatalk

I agree. If I am going to spend $180 on fittings, I want to to be factory replacement design, I don’t want to have to jury rig them to fit. I can make my own out of steel for a fraction of that cost.
For now I will just use the OEM and keep the Dorman in the truck as spares. After all, the OEM lasted 10 years and weren’t broken yet, I replaced them due to a small drip. So I will just keep my eye on them and put that $180 in the fuel tank.

 

[Geotrash]

I agree. If I am going to spend $180 on fittings, I want to to be factory replacement design, I don’t want to have to jury rig them to fit. I can make my own out of steel for a fraction of that cost.
For now I will just use the OEM and keep the Dorman in the truck as spares. After all, the OEM lasted 10 years and weren’t broken yet, I replaced them due to a small drip. So I will just keep my eye on them and put that $180 in the fuel tank.

To each their own, for sure. For me, the billet parts and upgraded hoses are a set-and-forget solution, for the kind of driving I do - towing a heavy trailer long distances in hot southern weather.

Another factor I consider is what the result of a failure of any failure-prone part would be. In the case of the tees, it has the potential to ruin my day at best, and at worst put me and my family in danger. I can think of many places where blowing a coolant tee would be a serious problem. To be clear, I agree that the likelihood of OEM tees failing is low, but the real cost for me is getting in there and doing the work to replace them. And, I know that I plan to keep my 2012 for another 10 years, so if I can take the likelihood of failure to zero for $100, more or less, it's worth it to me, but might not be to you, and that's okay.

It's a similar cost/benefit analysis I use when replacing something like a fuel pump with OEM vs aftermarket. The OEM pump is shown through the experiences of many here to be more reliable than aftermarket pumps, but costs $200 more. Since it's a PITA to do the job and the consequences of failure are significant, I'll spend the money for the OEM pumps on these trucks.

 

[gooffeyguy]

To each their own, for sure. For me, the billet parts and upgraded hoses are a set-and-forget solution, for the kind of driving I do - towing a heavy trailer long distances in hot southern weather.

Another factor I consider is what the result of a failure of any failure-prone part would be. In the case of the tees, it has the potential to ruin my day at best, and at worst put me and my family in danger. I can think of many places where blowing a coolant tee would be a serious problem. To be clear, I agree that the likelihood of OEM tees failing is low, but the real cost for me is getting in there and doing the work to replace them. And, I know that I plan to keep my 2012 for another 10 years, so if I can take the likelihood of failure to zero for $100, more or less, it's worth it to me, but might not be to you, and that's okay.

It's a similar cost/benefit analysis I use when replacing something like a fuel pump with OEM vs aftermarket. The OEM pump is shown through the experiences of many here to be more reliable than aftermarket pumps, but costs $200 more. Since it's a PITA to do the job and the consequences of failure are significant, I'll spend the money for the OEM pumps on these trucks.

The billet Ts wouldn't be what I'd be worried about, it'd be the bits of hoses and half dozen (well 5) clamps for each that's used to connect them.

Sent from my SM-G930V using Tapatalk

 

[Oldmopars]

What are the sizes of the hoses? 3/4 at the heater core? 5/8 heater hose? And 1/2 for the rear heat? Are both the same size? The billet one is only shown in one configuration.

 

[kbuskill]

What are the sizes of the hoses? 3/4 at the heater core? 5/8 heater hose? And 1/2 for the rear heat? Are both the same size? The billet one is only shown in one configuration.

They are both the same.

 

[Geotrash]

The billet Ts wouldn't be what I'd be worried about, it'd be the bits of hoses and half dozen (well 5) clamps for each that's used to connect them.

Sent from my SM-G930V using Tapatalk

Not an issue. The hoses are silicone and I used clamps designed for silicone hoses. They'll still be on the truck in 15 years when it's in the boneyard.

 

[Foggy]

Of course the Gruven is the best..
But, as to the original ???
The GM is better than the Dorman...
I have a friend that is a gm parts counter guy. According to him, the GM Tee's are an improved version
over the originals... That's according to him...
I just couldn't spend the $$ for the gruven, so I went with the GM Tee's... They were in stock and Inexpensive