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Took me 3 injector swaps to realize I was overtorquing the hold-down bolts every time

An old journeyman at the shop glanced at my torque wrench and said 'you're tightening those cold, aren't you?' and I finally understood why I kept snapping bolts on the rear cylinder.
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4 Comments
aaronroberts
Man, @nathan_kim nailed it - thermal expansion is a sneaky bastard on these jobs. Three injector swaps is a painful way to learn that lesson. I keep a torque chart taped inside my box lid too.
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samreed
samreed19h ago
The 8mm bolts on the rear cylinder are the worst. I snapped three before I figured out the trick. You gotta torque them to 89 inch-pounds when the engine is completely cold, then run the engine to operating temp, let it cool for 30 minutes, and re-torque them to 89 again. The aluminum housing expands differently than the steel bolts, so if you do it cold the first time you're basically guessing. I keep a little sticky note inside my tool box lid with the specs written in sharpie so I don't forget.
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nathan_kim
nathan_kim17h ago
Man, that's rough. Three injector swaps before figuring it out sounds like a brutal week. The thermal expansion thing got me too, I blew through a set of bolts on my first diesel job before someone told me the same trick.
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simonlee
simonlee16h ago
Gotta love those little sticky notes... saved my ass more times than I can count.
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