Duramax lower radiator hose o-ring

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Jtjasper2002

New member
Aug 5, 2013
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Hey guys I recently had my lower radiator hose o-ring start leaking on my lmm duramax. Every where I've read nobody knew where to get just the o-ring. Which resulted in a bunch of guys buying the new hose assembly just for the o-ring.

Well I have done a ton of research and I now have these replacement o-rings available for sale. Just send me a pm if you need one.
 
J

Jtjasper2002

New member
Aug 5, 2013
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I'm just trying to help people out. I've been there with my truck down because of a bad oring. The orings are nearly impossible to find unless you buy complete hose just for the oring.
 
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chuedepohl

New member
Aug 7, 2014
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Hey all, I had the leaky O-ring with my '06 LLY duramax. Rather than buy the new hose just to get the O-ring I did much recon (including seeing JtJasper2002 on eBay selling the O-ring for $20). With apologies to JtJasper, I'm going to reveal his secret. It's a Silicone 70 Durameter -226 (2" ID, 2 1/4" OD by 1/8" width) O-ring. I bought a package of 10 for $5.46 from McMaster-Carr (PN 9396K217) and it was delivered next day. I had tried 7 auto stores and 3 machine shops to no avail. The wife being a purchasing agent for a manufacturing company led me to McMaster-Carr.

Again, sorry JtJasper but I feel these forums are for helping a brother out rather than trying to profit.
 
LBZ

LBZ

Super Moderator
Staff member
Jul 2, 2007
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B.C.
chuedepohl said:
Hey all, I had the leaky O-ring with my '06 LLY duramax. Rather than buy the new hose just to get the O-ring I did much recon (including seeing JtJasper2002 on eBay selling the O-ring for $20). With apologies to JtJasper, I'm going to reveal his secret. It's a Silicone 70 Durameter -226 (2" ID, 2 1/4" OD by 1/8" width) O-ring. I bought a package of 10 for $5.46 from McMaster-Carr (PN 9396K217) and it was delivered next day. I had tried 7 auto stores and 3 machine shops to no avail. The wife being a purchasing agent for a manufacturing company led me to McMaster-Carr.

Again, sorry JtJasper but I feel these forums are for helping a brother out rather than trying to profit.
Click to expand...

Durometer 70 - 226 Got it.
Need one myself.
Thanks!
 
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Cannonball57

TD
Sep 26, 2010
2
0
0
I don't know if this page is still visited, but the leak is still active (especially if you've purchased a Mishimoto radiator). Mishimoto sent me what should have been a larger diameter O-ring, but it was the same as the OEM lower hose I purchased on internet. I went to Masters-Carr and spent $30.00 for 3 sets of O-rings of which one I'm sure will work. The first is the same as the original width of 3/32" Part number: 9396K88. The second is 1/4" width, but smaller inside diameter and the third is 1/4" width with the same ID and OD as original. I plan on testing the 1/4 " when it gets warmer, since the leak isn't really bad. I've also heard of using grease on the O-ring to see if it helps seal. Why GMC went with such a flimsy idea is beyond me, but putting one of the water pumps bolts behind the harmonic balance is even more idiotic.
 
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autoaddictions

New member
Jan 26, 2016
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part # for o-ring that you can get at autozone

I had to replace my radiator in my 2006 Silverado and the original oring was worn and it leaked as soon as I filled the new rad with fluid. A search here found a mc master carr part # and somebody on the fourm selling them for 20 bucks. I needed my truck running same day so I went to auto zone and searched there hundreds of gaskets and I found the perfect fit.

Felpro part # 35705 or you can use #35744 !! Both are Thermostat gaskets for a VW 2.0 engine. But they fit perfect!! cost $1.69 each.

I hope this helps somebody get going back on the road a bit faster than the previously posted solutions.
 
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Cannonball57

TD
Sep 26, 2010
2
0
0
Cannonball57 said:
I don't know if this page is still visited, but the leak is still active (especially if you've purchased a Mishimoto radiator). Mishimoto sent me what should have been a larger diameter O-ring, but it was the same as the OEM lower hose I purchased on internet. I went to Masters-Carr and spent $30.00 for 3 sets of O-rings of which one I'm sure will work. The first is the same as the original width of 3/32" Part number: 9396K88. The second is 1/4" width, but smaller inside diameter and the third is 1/4" width with the same ID and OD as original. I plan on testing the 1/4 " when it gets warmer, since the leak isn't really bad. I've also heard of using grease on the O-ring to see if it helps seal. Why GMC went with such a flimsy idea is beyond me, but putting one of the water pumps bolts behind the harmonic balance is even more idiotic.
Click to expand...

4-2-2016 - If you buy the O-ring (9396K88) from Masters-Carr and coat the Mishimoto aluminum lower outlet and O-ring with Hylomar Universal Blue I guarantee it will not leak. I've tried the so called silicone lubricant sealers and after time it starts leaking again. Amazon is the cheapest price on the Hylomar.
http://www.amazon.com/Hylomar-Unive...psc=1&redirect=true&ref_=od_aui_detailpages00

You can also check out the properties of the Hylomar Blue on:

https://www.youtube.com/watch?v=yXiVZIBoHL0
 
Jeff P

Jeff P

hail the V8 diesel
May 28, 2008
34
0
6
Queensland Australia
Hi guys I will just add to this some information I have found out ,there are two different size o-rings my original lower radiator hose has the -226 o-ring CAT P/N 8M4436 silicone (70) and the new hose I fitted awhile ago has a larger diameter -329 now you have two options 6L1651 being silicone (70) and Cat now use EPDM (70) for their cooling system o-rings and the p/n for this is 5S1105 hope this helps even here in Australia Cat o-rings are easy to get !
Jeff
 
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Cooper2

New member
Nov 22, 2017
1
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0
lml lower radiator o-ring

Does anyone know if these #226 o-rings will work on a 2012 lml lower radiator?
 
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