The LS1 was the official replacement for the LT1, and it was used more widely. Being younger, it benefited from a more modern architecture but that doesn't necessarily mean that the engine in the C5 Corvette is problem-free. The small-block V8 is known to struggle with poor piston ring seals, oil- and water-pump failure, pushrods that get bent, and piston slap (this is when pistons rock from side to side in the bore). Piston-ring seal failure may occur because of a bad quality seal used by GM on its LS1. As soon as wear takes place, oil may find its way into the combustion chamber. This results in excessive oil consumption and blow-by. Oil will also leak into the PCV valve. Once this takes place, excessive oil consumption, piston slap, blue smoke from the exhaust, and rough idling will occur. Piston seal replacement is the only option to consider but does cost a pretty penny as the entire powertrain will need to be disassembled. It is advised that you consider an upgraded set of seals designed by an aftermarket manufacturer.
A bad water-pump shaft and gasket often lead to water-pump failure. Coolant leaks throughout the engine bay are signs that this has occurred. Do not leave it untreated, because the engine may overheat, which can lead to gasket or even engine failure. The LS1's water pump has been known to give in after 100,000 miles with replacement being the only ideal solution. The oil pump is just as problematic as the water pump as it struggles with cavitation if you rev the engine past 6,000 rpm, where the pump is unable to deliver enough oil for engine lubrication. The pressure-release valve is another compromised component of the pump and can give in. Due to this, air is pulled into the oil which causes air cavities. Severe damage can be caused to the internals because of this. A low or zero oil-pressure light will let you know that the oil pump may be faulty. If this is the case, you'll have to replace the pump or valve, depending on which part has failed. You also need to avoid revving the engine above 6,000 rpm.
Bent pushrods are another symptom of revving the LS1 beyond 6,000 rpm. At this engine speed, the lifter over-exerts itself which tilts the pushrod out of place. When it returns down, it will be misaligned and bend. Excessive bending may cause the pushrod to snap, which will lead to total engine failure. Ticking noises from the engine or cylinder misfiring, poor idling, or bad timing, are key indicators that pushrods are bent. Installing new pushrods is the only way forward here if the damage is not too severe. The part is inexpensive at $27 each but the labor can range anywhere from $2,000 to $3,000 depending on what other components have been damaged.
Piston slap is a byproduct of failing piston seals and is understood to be the most common flaw of the LS1. In this instance, the piston will rattle against the cylinder sleeve if the clearance between the cylinder walls and rings increases past the required space. Be on the lookout for a ticking or slapping noise that emits from the powertrain before it has reached an adequate operating temperature. You'll also be able to see an excessive amount of oil consumption. There isn't a permanent resolution for this issue other than a routine and thorough inspection of the piston rings as indicated above. Piston slap will take place at low temperatures before the aluminum block has expanded.
Mileage: Water-pump failure happens after 100,000 miles. Bent pushrods may occur when the engine speed rises over 6,000 rpm.
Cost: A new set of piston rings for the LS1 costs $61 but the labor costs are substantial as it requires a powertrain disassembly. A water pump and gasket will set you back $509. A new oil pump is priced at $136 and the release valve will add $8. Each pushrod costs $27, but expect labor to be anywhere between $2,000 and $3,000.
How to spot: Excessive oil consumption, blue smoke from the exhaust, and rough idling usually indicate failed piston rings. Coolant leaks throughout the engine bay signal a failed cooling system. A low or zero oil pressure light reflects a faulty oil pump. Ticking noises from the engine or cylinder misfiring, poor idling, or bad engine timing could translate to pushrods being bent.