The ruptured water main that brought a major east-metro freeway to its knees this week was cracked lengthwise, it was discovered Tuesday.

Crews removed the 12-inch pipe from its casing and were preparing to install a new one, taking the first steps toward reopening the busy stretch of Interstate 694 through Oakdale.

“Based on our findings, all joints and the casing appear to be in good condition,” said Shawn Nelson, the city’s utilities superintendent. “It appears that the pipe may have been leaking slightly prior to the incident, which could be due to several possible causes including movement in the ground and roadway work.”

About 5 miles of the freeway remained closed, possibly into next week, after the leak created a washout Sunday morning that made it unsafe to drive.

The stretch of freeway, which normally accommodates as many as 87,000 vehicles a day, won’t reopen until at least Friday and probably later because of reconstruction work, said Kevin Gutknecht, a Minnesota Department of Transportation spokesman.

The cost of repairs won’t be known for several days, MnDOT and city officials said.

Oakdale crews were hoping to restore water service to 10 remaining households by the end of Tuesday.

The water main, installed in 1964, serves the central part of Oakdale from two nearby water towers. It was in surprisingly good condition despite its age and the crack, which was several feet long, Nelson said.

“We have seen cracks similar to this one, not as long, that appear to possibly be from stress on the pipe,” he said.

Erosion caused by leaking water left a culvert-sized hole under the north and south driving lanes a few miles north of where I-694 intersects with I-94 between Oakdale and Woodbury. An estimated 1.5 million to 2.5 million gallons of water escaped, Nelson said.

Nobody was injured and the driving surface remained intact, though it wasn’t safe for vehicles due to the unstable base below it, Gutknecht said.

Massive backups occurred after MnDOT initially shut down a 2-mile stretch between 10th and 34th avenues, and later Sunday closed 5 miles. That sent motorists on miles-long detours along Hwy. 36, I-35E and I-94, and traffic jammed nearby arterial streets Tuesday as drivers tried alternate routes to avoid snowfall-induced commuter backups.