Heating Oil Basics → Running Out of Oil

What to Do If You Run Out of Heating Oil

Quick steps: Check if you're truly empty → Call for emergency delivery → Add 5-10 gallons of diesel as a temporary fix → Bleed the fuel line → Restart the burner.

If your heating oil tank just ran dry, don't panic. Your house won't freeze immediately, and there are steps you can take right now — even before a delivery truck arrives.

Here's what to do, in order.

1. Check If You're Actually Empty

Before assuming the tank is dry, check a few things:

Look at the gauge. If it reads below 1/4, you may be very low but not completely empty.
Use a measuring stick. Dip a clean stick or dowel into the tank fill pipe. If it comes up dry, you're out. If there's an inch or two of oil, you may still have 5-10 gallons — enough to run the burner for a few hours. See how to measure oil manually.
Listen to the burner. If it's running but cycling on and off rapidly, the tank may be nearly empty and pulling air.

If you're truly empty — dry stick, burner won't fire — move to the next step.

2. Call for an Emergency Delivery

Most heating oil companies offer emergency or same-day delivery, but expect to pay a premium — often $50-150 more than a regular delivery, plus a higher per-gallon price.

Tips for calling:

Call your regular supplier first — they may waive the emergency fee for existing customers
If your supplier can't come today, call other local companies. Many will deliver to non-customers in emergencies
Ask for the minimum delivery (usually 100 gallons) to keep the cost down
If it's after hours or a weekend, check for 24/7 emergency delivery services in your area

While you wait for delivery, move to the next step — you can get heat running in under an hour.

3. Add Diesel Fuel as a Temporary Fix

This is the fastest way to get heat back. #2 diesel fuel is essentially the same product as #2 heating oil. The main difference is that road diesel has taxes and a different dye. It is safe to use in your oil burner.

Here's how:

Go to any gas station with a diesel pump
Fill a clean 5-gallon gas can with diesel fuel (NOT gasoline — never put gasoline in your oil tank)
Pour the diesel into your oil tank through the fill pipe (the capped pipe on top or side of the tank)
5-10 gallons is enough to run your burner for 1-2 days

Use #2 diesel only. Do not use gasoline, kerosene blends, or any other fuel unless your burner manual specifically allows it. Gasoline in an oil tank is extremely dangerous.

Rough guide — how long will it last?

5 gallons ≈ 12-24 hours (average home)
10 gallons ≈ 1-2 days

Actual usage varies by temperature, home size, and insulation. A 5-gallon can of diesel costs roughly $20-25 — far cheaper than an emergency delivery surcharge.

This is a temporary fix, not a long-term solution. Schedule a proper delivery as soon as possible.

4. Bleed the Fuel Line

When your tank runs completely dry, air gets into the fuel line. Even after adding oil or diesel, your burner may not start because it's trying to pump air instead of fuel. You need to bleed the line.

Before you start: If you are uncomfortable working around the burner, smell oil strongly, or see oil pooling on the floor — stop and call a professional. Bleeding the line is safe and straightforward for many homeowners, but it is not required. A technician can do this for you.

What you'll need:

A 3/8" or 1/4" wrench (or adjustable wrench)
A small container or rag to catch oil drips

Steps:

Find the bleeder valve on your fuel pump — a small hex nut, usually on the left side of the burner unit
Place your container or rag underneath the valve
Loosen the bleeder valve slightly — about a quarter turn. Do not remove it completely
Press the reset button on the burner (usually a red or black button on the burner control box)
You'll hear the fuel pump start. Air will hiss out of the bleeder valve, followed by sputtering, then a steady stream of oil
Once you see a solid, bubble-free stream of oil, tighten the bleeder valve
The burner should fire within a few seconds

If it doesn't fire after the first attempt, wait 60 seconds and try again. It may take 2-3 bleeds to fully purge the air.

Warning: Only press the reset button 2-3 times maximum. Pressing it repeatedly can flood the combustion chamber with unburned oil, which is a safety hazard and will require a technician to clean up.

5. If the Burner Still Won't Start

If you've added fuel and bled the line but the burner still won't fire:

Check the thermostat — make sure it's set above room temperature and switched to "heat"
Check the circuit breaker — make sure the breaker for the furnace/boiler hasn't tripped
Check the emergency shutoff switch — there's usually a red switch at the top of the basement stairs or near the burner. Make sure it's in the "on" position
Look for an error code or lockout light on the burner control box

If none of that works, call a heating technician. Running out of oil can sometimes cause sludge from the bottom of the tank to clog the fuel filter or nozzle, which requires professional service.

While you wait, see What to Do When You Lose Heat in Winter for tips on keeping your house warm and protecting your pipes.

6. Prevent It From Happening Again

Running out of oil is stressful, expensive, and can damage your heating system over time. Here's how to avoid it:

Don't rely on the gauge alone — they're imprecise, especially near empty. Measure your oil manually for accuracy.
Track your usage over time — knowing your daily burn rate helps you predict when you'll run low. See How to Estimate Heating Oil Usage.
Order at half a tank — don't wait until you're at 1/4. That leaves enough buffer for delivery delays and unexpected cold weather.
Pay attention to weather — a cold snap can double your usage overnight. See How Long Does Heating Oil Last in Winter?

Running out once is understandable. Running out twice is preventable.

Frequently Asked Questions

Can I put diesel fuel in my heating oil tank?

Yes. #2 diesel fuel is essentially the same product as #2 heating oil and is safe to use as a temporary substitute. Pour 5-10 gallons of diesel into your oil tank fill pipe to get your burner running while you wait for a proper delivery. Never use gasoline — it is extremely dangerous in an oil burner.

How do I bleed my furnace after running out of oil?

Locate the bleeder valve (a small hex nut on the fuel pump). Place a container underneath, loosen the valve a quarter turn, then press the burner reset button. Air will hiss out, followed by sputtering, then a steady stream of oil. Once you see solid, bubble-free oil flow, tighten the valve. The burner should fire within seconds. Only press the reset button 2-3 times maximum.

How much does emergency heating oil delivery cost?

Emergency deliveries typically cost $50-150 more than regular deliveries, plus a higher per-gallon price. After-hours and weekend deliveries cost even more. Call your regular supplier first — they may waive the emergency fee for existing customers.

Why won't my furnace start after I added oil?

The most common cause is air in the fuel line. When a tank runs completely dry, air enters the line and the fuel pump can't draw oil. You need to bleed the line to purge the air. If bleeding doesn't work, sludge from the bottom of the tank may have clogged the fuel filter or nozzle, which requires a technician.

How long will 5 gallons of diesel last in my oil burner?

Roughly 12-24 hours for a typical home, depending on outdoor temperature, home size, and insulation. Ten gallons will last approximately 1-2 days. This is a temporary fix to keep your heat running while you arrange a proper oil delivery.

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