2003 C5 Common Problems
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All known issues: 2003 C5
Known issues reported for the 2003 C5
On C5 and C6 Corvettes, the oil pressure sender commonly fails, causing the gauge to read zero, max or jump around. The engine is often fine, but you can't assume that. Always confirm with a mechanical gauge before driving.
C4, C5 and C6 Corvettes rely on electric cooling fans. When a relay, fan motor, sensor, fuse or wiring fails, the car may overheat in traffic or with the A/C on but run fine on the highway.
The harmonic balancer (crank pulley) on C5 and C6 LS engines can develop a visible wobble. It happens when the rubber ring between the hub and outer ring breaks down, or when the balancer has moved on the crank snout, often after a previous repair or pulley swap. A wobbling balancer can throw the belt and, if it has moved, can point to a deeper crank problem.
C5, C6 and C7 Corvettes use sealed hub bearing assemblies. They wear over time, especially with wide tires, track use or impacts. A failing hub causes a hum or growl that changes with speed and cornering.
The C5 uses an electronic steering column lock. When the lock motor or its sensing fails, the Driver Information Center can show "Service Column Lock" and the car may refuse to start or keep the steering locked. It's one of the best-known C5 problems.
The C5 connects the engine to the rear transaxle with a torque tube that has a driveshaft supported by bearings in rubber mounts. With age, the rubber and bearings wear and cause rumbling, groaning or rattling, often at idle or in certain RPM ranges.
C4 and C5 Corvettes use electric motors to raise and lower the headlights. With age, the motors, their internal gears or bushings, and the control circuits wear out. A headlight may stay down, stay up, move slowly or move only on one side.
The C5 has two fuel tanks, each with its own level sender. Owners commonly report a fuel gauge that reads wrong, jumps around or shows empty with fuel in the tanks. The usual cause is worn or contaminated sender contacts.
From the C4 onward, Corvettes have many electronic modules that draw small amounts of power with the car off. Add aging batteries, aftermarket accessories, or a module that doesn't go to sleep, and the battery can go flat in days or weeks. Storage without a maintainer is the most common cause.