Is this the updated oil cooler? - Chevy and GMC Duramax Diesel Forum
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post #1 of 2 (permalink) Old 07-01-2019, 08:31 AM Thread Starter
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Join Date: Apr 2014
Location: Sylmar CA
Posts: 39
Is this the updated oil cooler?

Sorry for the lengthy back story. I ha e some questions about this oil cooler. I've disassembled my LB7 after finding significant amount of coolant in my oil. Injectors where in bad shape, knew I had a small exhaust leak and simply wanted more power. I suspected a head gasket and removed the cylinder heads. It turns out my head gaskets were probably fine but had 2 injector cups leaking on cylinders #6 & #8. The heads have been resurfaced and Ready to be reinstalled with fresh Mahle gaskets, still awaiting the arrival of my ARP stud kit. I decided I'd like to be more thorough and suspected other issues based on previous troubles.

I suspected a issue with my oil cooler for nearly 2 years. Somebody made a real mess of it at some point with gasket sealant all over it. My oil cooler has leaked oil externally in the past and I just retightened the nut and took the easy way out hoping the issue was fixed. Not really knowing what the nut did outside of it being a oil cooler nut that went onto a stud. Well now I know it seals the staked plate oil cooler inside a coolant reservoir. And while I had fair warning it leaked out out the whole the stud went through tightening it wasn't really a fix. That nut kept coming loose and leaking oil all over my front Differantial. I eventually cleaned it with carb cleaner and used Loctite when I retightened it. Though I knew I could have a bigger problem, time passes.
I removed the oil cooler and jury rigged a old aquarium full of water to pressure test it. With some plexiglass bolted to the flanges, 1 cheap oil filter and some air compressor fittings. It failed my pressure test. Today I Disassembled the oil cooler. I found fresh bright green coolant inside the stacked plate oil cooler just inside the seal. Coolant that has not yet mixed with the oil. I figure this can only happen when the truck sits because oil pressure would have washed oil the other direction.
I had no metal shavings on the oil or my old oil filter. I dont see any proof of metal shavings at all. So theoretically I can reseal and reinstall this oil cooler. The rebuild kit has a seal that Is meant to lay in a groove on the cover. Though the previous person the fiddled with this oil cooler didnt use any seal at all just a RTV sealant (Gray or Black). There is a grove in the cover for the rubber seal that came with the rebuild kit. So I assume this is the updated oil cooler but Dont know for sure. Which leads me to my question: Is this oil cooler is the updated version? Or the original LB7 oil cooler?

2003 Chevy Silverado 2500HD W/ LB7 duramax w/Allison trans
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post #2 of 2 (permalink) Old 07-01-2019, 08:44 AM Thread Starter
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Posts: 39
I few pics
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2003 Chevy Silverado 2500HD W/ LB7 duramax w/Allison trans
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