* Specific Engine: The 1989 Chevy 2500 came with several engine options (e.g., 6.2L diesel, small-block gas V8). The exact location of the frost plugs and their suitability for a block heater may vary slightly depending on the engine.
* Block Heater Type: The design of the block heater itself might influence the ideal placement. Some heaters are better suited to certain plug locations due to their size and shape.
* Accessibility: Consider how easy it will be to install and access the heater in each location.
Recommendation: Before drilling, carefully inspect all frost plugs. Choose the lower passenger side if it's a suitable size and location for your specific heater and engine. Consult a repair manual specific to your 1989 Chevy 2500's engine to confirm the best location and to see diagrams of the engine block. A good manual will show you the frost plug locations clearly.
Caution: Drilling into the wrong location can cause significant damage to your engine. If you are not comfortable performing this task yourself, it is best to take your vehicle to a qualified mechanic.
