Nick Mead, who runs Northampton tank events company Tanks-A-Lot, and Todd Chamberlain bought the Chinese-made T54 tank for £30,000 on eBay.
Footage taken by Mr Mead shows Mr Chamberlain inspecting the tank's diesel container, and pulling out the gold.
An excited Mr Mead can be heard saying: "Is that what I think it is? How heavy is it? Seriously?! Is that gold? Oh god, that’s about five or six kilos. Wow, good here init [sic].
The pair expected to find old guns inside the tank
"See how many there are, find the rest! Yeehaah! What are we going to do with them?"
But rather than stashing the precious metal, the pair decided to call the police.
Mr Mead continued: "It's not something I'd thought I'd be doing, finding b***** great bars of gold hidden in a tank. Absolutely incredible.
"But, we've got to ring the police. I don't know whether this is millions or hundred of thousands worth. But one thing is for certain, I don't want it lying around my office."
Todd Chamberlain inspects the tank's diesel container
Two police officers took the bounty away and gave Mr Mead and Mr Chamberlain a receipt which they have now stored in a safe deposit box in London.
The bars are believed to be loot taken by Iraqi soldiers during the invasion of Kuwait in 1990.
Mr Mead purchased the tank, which was restored by its previous owner, in exchange for an Army lorry and an Abbot self-propelled gun. His collection comprises some 150 military vehicles.
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Mr Chamberlain estimates the gold's value at £2million
Rather than stashing the precious metal, the pair decided to call the police
The military buff was hoping to launch a 'From Russia With Love' Experience which allowed punters to drive Russian tanks, Mail Online reports.
Mr Chamberlain, who estimates the gold's value at £2million, told The Sun: "We didn't know what to do.
"You can't exactly take five gold bullion bars down to Cash Converters without questions being asked, so we called the police."
Mr Mead added: “Even if I don’t get any of the gold back I will still have my beautiful tank.”