What's going on with my tank?

Eloise

I have an indoor oil tank, 330 gallon capacity. I have had it filled (whistle indicator going off) twice in the last three weeks. Both times, the gauge showed full initially. But when I checked the gauge the next day, it indicated my oil level was down to a quarter of a tank. I assumed the gauge wasn't working properly; but I had it checked and the plumber used a flashlite to confirm that indeed I was down to a quarter of a tank and the gauge was working properly. My question is, why would the whistle indicate that the tank was full when it wasn't? Why did the whistle go off when both times I had the tank filled, it only took 50-70 gallons of oil? Do I need to replace the tank, or is there some mechanism that isn't working properly? THANK YOU!!!

STEVEusaPA

The whistle is a stem attached to the vent pipe. It extends down about 6". The idea is to prevent the tank from getting completely full, allowing room for expansion.
But if you truly lost almost a 1/4 tank in about a day, then you:
1. Have an oil leak (is your supply line buried?)
2. Your constantly burning about 3 gph.
Next delivery, if you can do this:
Check the gauge right before delivery. Tell the driver to fill the tank on low speed. Some companies blast the oil into the tank at over 90 gal per minute. The oil surges and gets foamy (like pouring soda into a glass) stopping the whistle. Then it settles down and you could be less then 7/8 full. Check the gauge about 10 minutes later. Check it the next day. Should be about the same. If not, explore 1 or 2 above.

icesailor

I'm confused about your problem, but there have been a batch of gauge whistles there the "cork" on the end of the gauge isn't really oil resistant. It isn't a cork at all, just some plastic float. The float absorbs oil and looses its ability to float over a day or so. Unscrew the clear plastic gauge cover and pull the indicator up as high as it will go. You will hear the oil splash when you slowly ley it go. Put the gage glass back on. Note the level. Come back in a few hours. If the level has dropped appreciably, the float may have lost its buoyancy. If there is an empty and plugged hole in the tank, get a new gauge only and put the new gauge in the empty hole. Taking particular care with the instructions so you don't bend the float linkage on the side of the tank.

Eloise

Thanks so much Steve and IceSailor....that helps!