Diesel Heater Maintenance Schedule

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This schedule outlines routine checks, annual servicing tasks, and long-term maintenance for diesel air heaters used in camper vans, motorhomes, boats and off-grid vehicles. Regular upkeep improves reliability, reduces soot buildup and extends heater lifespan.

Daily / Before Each Trip

• Visually check that the exhaust and air intake are not blocked by mud, snow, debris or vegetation.
• Listen for unusual noises from the fan or fuel pump.
• Ensure the heater has unobstructed airflow at both the intake and warm-air outlet.
• Confirm the carbon monoxide (CO) detector is present and functioning.

Monthly

• Run the heater on maximum power for 10–20 minutes to reduce carbon buildup (a “burn-off cycle”).
• Inspect all visible fuel lines for signs of weeping, cracking or abrasion.
• Check electrical connectors for corrosion or loose contacts.
• Verify ducting is not crushed, kinked or rubbing against bodywork.

Every 3–6 Months

• Clean the heater’s cold-air return vent and warm-air outlet grilles.
• Inspect exhaust clamps and mounting hardware for tightness.
• Examine the fuel filter (if externally accessible) and replace if dirty.
• Check battery voltage and charging system performance, as low voltage contributes to poor ignition and soot buildup.

Annually (Full Service Recommended)

• Remove and inspect the glow plug; clean or replace if fouled or worn.
• Inspect the combustion chamber for excessive soot; clean if necessary.
• Clean or replace the fuel filter.
• Check all seals around the heater mounting plate and floor penetration.
• Inspect fan motor for dust buildup and assess bearing condition.
• Verify exhaust and intake routing for corrosion, damage or leaks.
• Test the heater through a full start-run-shutdown cycle.
• Replace any hardened or damaged rubber fuel line sections.

Every 2 Years

• Replace glow plug as preventative maintenance (recommended for frequent users).
• Replace exhaust gasket(s) and inspect muffler for corrosion.
• Inspect wiring harness for wear, especially at entry points and sharp bends.
• Consider replacing the fuel pump if startup reliability declines.

Long-Term / As Needed

• Overhaul burner chamber if performance drops significantly despite routine cleaning.
• Replace fan motor if it develops persistent squealing, grinding or wobble.
• Replace ducting if it becomes brittle, flattened or heat-damaged.
• For heaters used in damp or coastal environments, inspect all metal components annually for corrosion.

Storage (Off-Season)

• Run the heater for 10–15 minutes at high power once per month to keep components dry and prevent carbon buildup.
• Check that fuel in the tank is clean and appropriate for seasonal temperatures.
• Ensure the exhaust remains clear of nesting insects, mud or debris.

Notes

• Diesel heaters perform best when run hot regularly; repeated low-power operation leads to soot accumulation.
• Using clean, good-quality diesel significantly reduces burner fouling.
• Always follow manufacturer-specific maintenance intervals when available.