One of the first. This is a 2001 LB7 Duramax, from the very first year GM put the 6.6L diesel into the Silverado and Sierra heavy-duty trucks. It’s in the workshop for a cylinder head overhaul, and to fix some rather average previous repairs along the way.
What came in
The short version: it overheated. If it hadn’t, it would still be going strong. The LB7 is a tough engine, and properly looked after these are genuine million-kilometre engines. But an overheat on any diesel puts the cylinder heads under enormous stress, and once a head gasket lets go or a head warps, it’s a head-off job.
On top of that, this truck had been worked on before, and not well. Part of the job was going through what had been done previously and putting it right, because there’s no point fitting a reconditioned head on top of someone else’s shortcuts.
What we did
Head work on a Duramax means the cab comes off. There’s no sensible way to get at the heads, injectors and turbo on these trucks with the body in place, so the photo shows the engine sitting in the bare chassis with the freshly overhauled head fitted and the turbo sitting on top ready to go back on.
- Cab lifted off for full access to the engine
- Cylinder heads removed, cleaned, pressure tested and checked for flatness
- Heads overhauled with new valve gear and reassembled – note the fresh springs, rockers and assembly lube in the photo
- Block deck checked before the heads went back on with new head gaskets and bolts
- Previous repairs inspected and corrected as found
- Turbo, intake and ancillaries cleaned and refitted, then the engine run up and checked before the cab goes back on
A note on the LB7
The LB7 was built from 2001 to 2004 and it’s a bit of a favourite. It’s pre-emissions, so there’s no DPF, no EGR and no DEF to worry about, and the bottom end is very strong. Its known weak points are the injectors (which live under the valve covers, so they’re a big job) and, like any diesel, the cooling system. Keep the coolant fresh, keep the radiator clean, don’t ignore a temperature gauge that’s creeping up, and the engine will outlast the rest of the truck.
Duramax specialists in Perth
We work on Chevrolet and GMC heavy-duty trucks every week – LB7 through to the current L5P – and we do the big jobs in-house: diesel repairs, cooling system repairs, head overhauls and full engine rebuilds. If your Duramax is running hot, down on power, using coolant or just not sounding right, bring it to someone who knows the engine.
Call (08) 9258 6409 or visit Unit 5/51 Division Street, Welshpool. Based in Welshpool – servicing Perth.
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