It's a sure sign things are getting tough when people at the Federal Energy Administration start stealing each other's radiators. Well, things are getting tough.

What may be the first recorded act of radiator rustling in government - if not the world - took place recently at the FEA headquarters here. FEA is the place whence the American people get directives, advice and orders on how to save energy.

It happened something like this:

An FEA woman, who hopes to remain nameless, complained that sometime after Christmas her office got cold. Up until that time, even in cold weather, it had been pleasant. A fan or blower device near the office radiator (which had a cover on it) was thought to be the culprit.

Building maintenance experts, who know about such things, did whatever one does to the heat distribution fan to make it blow harder. The woman said it still was too cold. More adjustments to the fan. Still too cold.

Finally, the chief engineer came up to take a look. He said the fan was working all right but agreed that it was a mite cool. He decided to check the radiator. The cover was carefully removed. No radiator!

The investigation into the disappearance of the seventh floor office radiator is proceeding slowly. Insiders suspect that rather than the mob, it could be that the radiator was quietly removed and installed in the office of some VIP at the FEA who was suffering from cold feet.