Glow Plugs and Controllers for Diesel Trucks
Glow plugs are the starting aid for diesel engines, heating the pre-combustion or combustion chamber to allow reliable cold starting. In commercial vehicles, particularly those operating early morning starts in winter conditions, a functional glow plug system is the difference between a productive first run and a delayed departure. Truckstop stocks glow plugs and glow plug controllers for HGVs and trucks across all major makes.
Glow Plug Controllers: Why They Matter
The glow plug controller manages the voltage and duration of the glow plug heating cycle. A faulty controller can cause plugs to receive incorrect voltage, leading to either insufficient pre-heat or, in some cases, glow plug burnout. Replacing the controller at the same time as the plugs is good practice on older or high-mileage engines where controller age is likely to be a factor.
How do I know if the glow plugs need replacing on my truck?
The most common symptom of failed or degraded glow plugs is difficulty starting in cold conditions: long cranking times, white smoke on cold start and rough running immediately after starting. Many trucks have a glow plug warning indicator that illuminates if the system detects a fault. Testing individual plug resistance with a multimeter confirms which plugs have failed. All plugs in the set are usually replaced together.
What is the difference between pencil glow plugs and ceramic glow plugs?
Pencil glow plugs are the traditional steel-sheathed type used in older commercial vehicle engines. Ceramic glow plugs use a ceramic heating element that reaches operating temperature faster and is more durable. Most modern commercial vehicle diesel engines use ceramic glow plugs. The correct type is determined by the engine specification; check the product listing or contact the Truckstop trade team to confirm.
Do you stock glow plug controllers as well as the plugs themselves?
Yes. Glow plug controllers and relay units are stocked alongside the plugs. If the controller fault has caused glow plug failure, replacing both at the same time avoids a return to the same fault on the new plugs. Truckstop stocks controllers cross-referenced to specific makes and models.
