When my 1999 GMC Jimmy developed a connecting rod knock, I had to weigh my options. A remanufactured engine ($1800+) rivaled the value of the car. A junk yard engine (perhaps $600 to $800) seemed risky.
So I took apart the engine and installed a reground crankshaft (min. cost: $519). But it made sense to replace the piston rings, and a few other parts. The result: A (mostly) rebuilt engine that runs like new.
It's easy to let that defunct car sit untouched for a long time. Read: The Perils Of Procrastination When Your Car Needs Major Engine Work
Step 0 -
Deciding What To Fix
The only problem was a rod knock, so the engine did not need a total rebuild.
Step 1 -
Removing The Cylinder Heads
The exhaust manifolds are removed, the valve rocker arms and pushrods are removed, and the cylinder head bolts are removed in a certain order.
Step 2 -
Removing The Pistons
The connecting rod nuts are removed and the the piston tapped out of the cylinder. At this point I discovered which cylinder had the "rod knock". The bearing wasn't pretty.
Step 3 -
Removing The Crankshaft
The main bearings and rear oil seal are removed. The forging number is located on the crank so the right remanufactured crankshaft can be ordered.
Step 4 -
Cylinder Honing And Block Cleaning:
A special abrasive brush is used to create a certain scratch pattern on the cylinder walls. This is required when new piston rings are installed, so the proper amount of engine oil stays on the cylinder walls.
Step 5 -
Installing A New Crankshaft
A reground crankshaft and new bearings are installed, but each main bearing needs to be checked to make sure there is just the right amount of space for motor oil to lubricate the moving parts.
Step 6 -
Installing New Piston Rings
After the old rings are removed, the ring grooves need to be cleaned. Installing piston rings requires a special tool, which doesn't cost much.
Step 7 -
Installing The Pistons
Installing pistons requries a piston ring compressor. Even with this special tool, it's still a tricky job to slide the pistons into the cylinder bores. Then each connecting rod needs to be installed on the crankshaft and checked for the proper oil clearance.
Step 8 -
Installing A New Timing Chain And Cover
The old timing chain had some slack, so I bought a new chain and sprocket set. A new timing chain cover is required for this engine. Then the harmonic balancer was installed with a special tool.
Step 9 -
Installing The Cylinder Heads
The cylinder head mating surfaces are carefully cleaned and new head gaskets are set in place. The heads are installed with new Torque-To-Yield head bolts. The pushrods and rocker arms are installed.
Step 10 -
Installing The Exhaust Manifolds
The manifold mating surfaces are cleaned up and a new gasket is installed.
Step 11 -
Installing A New Oil Pump
For $60, a new oil pump is cheap insurance, but the oil pickup tube needs to be pressed into the pump, and it's NOT easy.
Step 12 -
Installing The Oil Pan And Oil Filter Adapter
Just before installing the engine back in the car, I installed the oil pan. It's also a good time to install the oil filter adapter and oil lines that feed the remote oil filter.
Also See: Cooling System Repairs
Replacing Intake Manifold Gaskets - GMC Jimmy / Chevy Blazer
This Jimmy would leak a gallon of coolant in 20 minutes of driving. The culprit: Blown intake manifold gaskets, probably caused years ago by GM's Dex-Cool antifreeze. Repair shops wanted $470 or more... I fixed it for $50.
Replacing Oil Cooler Lines - Jimmy/Blazer
The original tubing had a small leak and dripped oil all over the engine compartment.
Removing Air Ducting - Blazer/Jimmy
Also See: Moving The A/C Compressor For Easier Access To The Radiator Shroud
Replacing The Distributor Cap And Rotor
On A GM Truck
This 1996 GMC Yukon wouldn't start whenever the weather was damp and the engine was cold. Warming up the distributor cap with a heat gun would get the engine to start, but the proper fix was to just replace the worn-out distributor cap and rotor.
Also See: Cooling System Repairs
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