GM coolant elbow O-ring melted in one month. Why?

[ron350]

Thanks that made me laugh.

[MattStrike]

https://www.marcorubber.com/o-ring-chem ... -chart.htm

All you could ever want to know about O-rings there.

Don't coat your O-rings in RTV. RTV won't stop the failure you've experienced here, it might get by longer before it's a problem but that's not fixing it. Then the part is going to be stuck in the bore so next time it's a fight to get it out without breaking it. I've seen aluminum elbows break because of RTV, then RTV gets stuck in the bore and prevents a new O-ring from sealing properly.

Properly clean the bore and lube (silicone grease is safe for all o-rings except for silicone o-rings) it prior to installation. The lube prevents it from getting torn or pinched during installation.

The bore could have gotten corrosion in there or pitting or stuff like that. But that's easy to spot. It won't enlarge over time - the oring isn't hard enough to wear the aluminum.

GM o-rings appear to be standard SAE sizes. It's possible the aftermarket ones use standard metric sizes (especially if they are made in China by the lowest bidder), or simply the wrong size. GM and aftermarket claim to be EPDM. Various specific formulations of EPDM are good for 212-300F. The orange coating that melted is just a color coating that doesn't effect the function of the O-ring. Without access to the engineering information (as well as plant quality information), there's no way to know what's going on with the aftermarket O-ring.

[MattStrike]

I just found out that theoringstore.com has flourosilicone O-rings in these sizes for $0.78 and $0.86 each. HNBR are $0.21 and $0.23 each, EPDM are $0.07 and $0.08 each. I wonder what they charge for shipping?....

[Jazzy]

Thanks, MattStrike. I started learning about the O-ring business and I'm now just getting confused -- so many choices of materials. Too many choices of materials. I just one that's round and doesn't leak coolant out of my 3800 Series 2 coolant elbows. I will use the Real GM ones if it leaks again. The orange one that melted looked orange all the way through; here are the photos I put on my Amazon review, https://www.amazon.com/gp/product/B00S0 ... merReviews

I emailed today ACDelco directly about the problem, and will share the answer if they respond.

[ron350]

Jazzy the only o-rings that are supposed to be orange all the way through are silicone. It is possible some one mixed up silicone orange o-rings with GM orange painted o-rings. But now days you can probably buy any color o-ring you want from china.

The GM – Delco o-rings (25537068) and (24502846) will be black o-rings coated with orange paint for some reason. You should be able to scratch the orange coating off with your fingernail and make sure it is a black o-ring.

[Jazzy]

So if it was a silicon O-ring, maybe that is why mine melted in the green coolant flow?

[MattStrike]

No, silicone O-rings are good for 400F and are safe to use with automotive coolant (I have silicone coolant hoses everywhere on a bunch of my projects).

If you still have the bad O-ring cut it with a razor and see, if the color really is all the way through.

[Jazzy]

It was solid orange. The other elbow I installed at the same time was plastic, a "Genuine GM 24503423 Thermostat Bypass Pipe" from Amazon, and its two orange O-rings were only an orange coating over black bodied O-rings -- and they did not leak or look melted/dissolved.

[oooooo1]

I have no answers then, other than GM's quality is failing?

Hello, I just joined this group. I have heard about these o ring problems with the dorman part. I unfortunately had just ordered these a couple days ago and dont wanna do the job twice. I see your post that you have the GM orings and offered to send them out. Was wondering if you might send me some of the GM o rings for these elbows. I am located in Vermont. Also Is your name in reference to Haro BMX. just wondering because that is what I rode in my younger days. Brought back memories either way. Thx. Jay My email is u4q4q4q@gmail if u wanna get ahold of me there.

[harofreak00]

I have no answers then, other than GM's quality is failing?

Hello, I just joined this group. I have heard about these o ring problems with the dorman part. I unfortunately had just ordered these a couple days ago and dont wanna do the job twice. I see your post that you have the GM orings and offered to send them out. Was wondering if you might send me some of the GM o rings for these elbows. I am located in Vermont. Also Is your name in reference to Haro BMX. just wondering because that is what I rode in my younger days. Brought back memories either way. Thx. Jay My email is u4q4q4q@gmail if u wanna get ahold of me there.

I emailed you. I can mail you some.