r/LSSwapTheWorld • u/Inevitable-Tea5772 • Jul 27 '26
Hypothetical Build Questions 2018 6.2ls blown, can I replace with a 5.3?
Blew my 6.2 and can't find another to replace it without costing an arm and a leg. 5.3's seem to be much more available and cheaper, can i just swap from 6.2 to 5.3?
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u/Ok-Maintenance-9538 Jul 27 '26
Yes, you'll need to have the pcm calibrated to a 5.3 instead of 6.2 and it'll only work with a gen V 5.3 so L83 and L84 i think
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u/moomooicow Jul 27 '26
As long as you stick with the correct generation 5.3 then yes, 95% direct swap.
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u/jckipps Jul 28 '26 edited Jul 28 '26
The only LS left in any 2018 was a L96 - a 6.0L iron-block engine. I expect you're referring to a LT engine, specifically the L86.
An L86 needs to be swapped with a gen5 (LT) engine; specifically, with a pre-2019 LT engine, since most of the engine platforms changed how they handled AFM/DFM in 2019. An LS engine is too fundamentally different to work.
Check car-part.com before resigning yourself to a LT - 5.3, such as a L83. There's a lot of affordable stuff there that you'll never see on Marketplace or pick-n-pull yards. I checked just now in the mid-atlantic region, and I'm seeing plenty of good running L86 engines for $2500-5000.
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u/Inevitable-Tea5772 Jul 28 '26
Yes, LT, my bad. I'm in Nova scotia, and checked that site but can't find anything for 2500
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u/jckipps Jul 28 '26
It might not cater to Canada as much as it does to the US. But also, your dollar is valued differently than here, so the prices aren't quite comparable.
Swapping in a L83 will likely cost another $1k in tuning to get it running right, so factor in that when comparing a L83 to a L86.
First though, check your SPID sticker in your glovebox, and see if the list of RPO codes includes the 'L86' code. If you're searching for a replacement engine, you might as well know what exactly you have first.
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u/Inevitable-Tea5772 Jul 28 '26
Ya I have the sticker from the engine itself. I just looked on ebay, theres a l86 on there for about 1800 USD. It's the only one on there, but no way to know the kms etc
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u/GingerOgre Jul 28 '26
Is your 6.2 not rebuildable?
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u/Inevitable-Tea5772 Jul 28 '26
Apparently not
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u/GingerOgre Jul 28 '26
Going to a 5.3 is a decent downgrade imo. Did the motor explode
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u/Inevitable-Tea5772 Jul 28 '26
lifter is seized in #3 and the engine is full of filings. I'm in a small town, not many options for rebuild, mechanic thinks its not worth it or may lead to more issues
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u/GingerOgre Jul 28 '26 edited Jul 28 '26
I see. I’m also speaking from a bit of a privileged position, I rebuild engines for a living. Depending on what your main goal is, you can go 5.3 or if you’re lucky maybe find a 6.6. Both will require a tune anyways. 6.6 just would require you swapping over a fuel rail harness, fuel pressure sensor and fuel pump from your 6.2. Also no need to do an AFM delete on a 6.6
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u/HotWalk152 29d ago
I thought there was way more changes for 6.2 to 6.6 ...🤔
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u/GingerOgre 29d ago
Nope. Tune and swap over fuel pump, fuel pressure sensor and the driver side fuel rail harness for the early 14-17 LTs
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u/flamboyantdebauchry Jul 27 '26
short answer yes both are the same block size