Question
My parking heater ejects black soot from the exhaust. Is this normal?
Short Answer
A small puff at start is normal. Continuous black soot means rich combustion. Clean the air filter and chamber.
Causes
Clogged air filter, old fuel, soot buildup, wrong fuel pump rate. Any of these makes the mixture too rich.
Fix
Replace the air filter. Run the heater on high for 10 minutes. Clean the combustion chamber if soot persists.
What It Does
Continuous rich combustion coats the heat exchanger, reduces output, and eventually triggers overheat shutdown.
Prevention
Annual service. Use clean winter diesel. Avoid ultra-short cycles.
Result
Normal exhaust is nearly invisible. Black soot means service is due.
References
[1] European Union Regulation (EU) 2015/1188 on monitoring and reporting of CO2 emissions.
[2] European Union Regulation (EU) 2015/1186 on type-approval requirements for motor vehicles and engines regarding emissions.
[3] SAE International J1455: Recommended Environmental Practices for Electronic Equipment Design in Heavy-Duty Vehicle Applications.
[4] FCC Part 15 Subpart C: Intentional Radiators.
[5] ISO 6722: Road vehicles – 60 V and 600 V single-core cables.
[6] U.S. EPA Idling Reduction Fact Sheet for Heavy-Duty Diesel Vehicles.
[7] ISO 8820-2: Road vehicles – Time-lapse current-limiting fuses.
