can you use heating oil in a diesel car

[DiJameson]

No, you should not use heating oil in a modern diesel car. While both fuels are derived from similar petroleum base stocks, they are formulated for entirely different purposes. Using heating oil, also known as fuel oil No. 2, in your car's diesel engine can lead to severe engine damage, void your warranty, and is illegal for on-road use due to tax evasion.

The primary difference lies in the refining process and additive packages. Modern diesel engines, especially those from 2007 onward with advanced emissions systems, require Ultra-Low Sulfur Diesel (ULSD). ULSD has a strictly regulated sulfur content (a maximum of 15 parts per million) to protect sensitive components like the Diesel Particulate Filter (DPF) and catalytic converter. Heating oil contains significantly more sulfur, which can quickly clog and destroy the DPF, a repair costing thousands of dollars. Furthermore, diesel fuel contains lubricity additives and cetane improvers that are essential for proper fuel pump and injector operation; heating oil lacks these, leading to increased wear and potential failure.

Characteristic	Ultra-Low Sulfur Diesel (ULSD)	Heating Oil (No. 2 Fuel Oil)
Sulfur Content	≤ 15 ppm	Up to 5000 ppm (or more)
Road Taxes	Included in price	Not included; illegal for road use
Lubricity Additives	Required for high-pressure fuel pumps	Typically absent
Cetane Rating	Regulated for optimal combustion (~40-55)	Not regulated, often lower
Intended Use	Modern diesel engines with DPFs	Furnaces and boilers

In an absolute emergency, such as being stranded, using a small amount of heating oil might get you to a service station, but it's a significant risk. The potential for immediate damage to your emissions system and fuel injection components far outweighs any perceived short-term benefit. Always use the correct, taxed ULSD fuel specified for your vehicle.

[LaJoshua]

As a mechanic, I've seen the aftermath. It's a bad idea. That heating oil isn't made for today's tight-tolerance engines. It'll gunk up your diesel particulate filter faster than you can say "expensive repair." The sulfur clogs everything, and it doesn't have the lubricants your high-pressure fuel pump needs. You'll be looking at a bill that makes the fuel savings look like pocket change. Just don't do it.

[VonBeckett]

I looked into this to save money, but the math doesn't work. Sure, heating oil is cheaper at the pump, but that's because it doesn't include road taxes. It's tax evasion, plain and simple. More importantly, it lacks the additives that keep a modern diesel engine clean. You might save a few bucks now, but you're almost guaranteed a multi-thousand-dollar repair bill for your emissions system later. It's a terrible gamble.