Most shops in colder climates start to see an influx of customers with battery service needs as the holidays approach. Perhaps more than any other maintenance category, being proactive about taking care of your customers with dying or dead batteries is essential this time of year.
Crankcase vapors are routed through the positive crankcase valve (PCV). The PCV valve is a simple spring-loaded valve with a sliding pintle inside. The system allows the vapors to be siphoned into the engine using engine vacuum.
For some alternators, it’s normal to see as low as 13 volts. For some, a constant 13.6 volts is an indication of a problem. For others, it’s normal to see as high as 16 volts for long stretches. Still, it’s perfectly normal for others to see the alternator not charge at all intermittently.
The owner of this GM Duramax was headed to Montana on vacation with his family and camper trailer in tow. After stopping for lunch, the owner was dismayed to find that his Duramax immediately went into “limp mode” as the engine started.