A service road may have to close this weekend for urgent work at the Royal Sussex County Hospital, in Brighton.
The cooling system for the Thomas Kemp Tower needs to be replaced, hospital bosses said, and as a result new chillers would be put in place on Sunday (29 March).
They are hoping to deal with the issue before it affects patient care.
University Hospitals Sussex NHS Trust, which runs the Royal Sussex, said: “We apologise for the short notice we have been able to give for these urgent works and the inconvenience that they may cause.
“We have a situation with cooling systems to the Thomas Kemp Tower which our estates team have been working hard to organise urgent works to resolve.
“They have been able to line up all the required contractors to undertake the lifting of new chillers (into place) this Sunday which will allow resolution of the problem before it impacts critical clinical services.
“To undertake these lifts, a crane will need to be positioned in the centre of the North Service Road, requiring the use of the western end from Whitehawk Hill Road for vehicles to access the multi-storey car park.
“A Sunday has been selected as there will be the lowest possible number of vehicles accessing the North Service Road.
“We plan to open the west end from approximately 9am, lifting operations to commence at approximately 10am, and for all works to be complete by approximately 5pm.”