Oil tank won’t allow fuel to flow

aurora22

I have A 275 oil tank that is above ground and is under my frt steps.  My oil burner appears to act like I ran Out of fuel. I changed The filter and found is was empty. When I checked The fuel gauge it says there is a half tank. This is a old tank and there is definite sludge present. I diconnected The fuel feed line at the filter and used a air compressor to blow thru to make sure there isn’t a blockage. You can hear the air in the tank. It sounds like it’s bubbling. Problem is nothing is flowing out. Fuel line is dry

Jamie Hall

Fuel gauges have been known to lie.

Or, or in addition, if the tank has water or sludge in it, and it's below freezing where you are, it might just be frozen.

EBEBRATT-Ed

There may be a spare plug on top of the tank you can remove to check the oil level with a ruler.

Don't forget to replace the plug when you are done.

If the tank is sludged up or frozen at the bottom you can get some fittings and feed the burner through the top of the tank Keep the oil line up off the bottom a few inches. Make sure whatever you do is oil tight

HVACNUT

Definitely check the gauge. Unscrew the vial, lift the float and let it drop. No splashy, no oil. Be careful of the gaskets. 
Does the oil line come off the top or bottom of the tank? If it comes off the top, try filling the filter canister with fresh oil first. Remove the filter and fill to near the top. Then slowly put the filter back in. It won't overflow. Then prime the pump.

P.S. I hope you used very low air pressure with the compressor. Especially if the oil line is buried.