Restoration and improvements of West Smethwick Park and its historic structures will cost in the region of £5,557,000.
Sandwell Council has drawn up full proposals for work at the park which were backed by councillors on the planning committee this week.
Officials are awaiting a decision over funding from the Heritage Lottery Fund.
But Councillor Roger Horton said at the planning meeting on Wednesday night that he would give the plans the go ahead if a time capsule is protected.
He said: "This gets my approval if we can add a condition that the time capsule which was put there in 1995 is protected.
"I want to make sure it's covered so if it found when the working is being done then they will know what it is.
"I think this is the first time we've put down a condition on a time capsule."
Improvements will be made to the park's entrance, a new bandstand, restoration of paths and a drinking fountain.
The James Chance Memorial and the memorial to two airmen whose plane crashed in the park in 1944 will also be restored.
The lake at the park will also be improved along with a skate park and improvements to sports pitches, and electric and water points will be fitted for outdoor events.
Sir James Chance, whose family ran glassworks Chance Brothers & Co in Spon Lane, Smethwick, donated the park to the people of the town in 1875.