Dozens of OC Transpo buses are off the road today because of a defect in 43 articulated buses recently purchased by the city.

OC Transpo general manager Alain Mercier explained the situation in a memo to city council early Friday morning, saying the service interruptions are the result of a defect that could potentially crack engine mounts.

"While the defect does not present an immediate threat to passenger safety or the operation of the bus, it is not known how long the buses could continue to operate in this condition," wrote Mercier.

As a result, 35 buses were removed from the roads immediately.

The situation only led to the cancellation of 11 out of 4,500 routes that OC Transpo services on a normal weekday, according to the city. Service interruptions are not expected beyond Friday.

A city spokesperson said winter storms often lead to more of a disruption than the one caused by the defect.

Maintenance staff worked throughout the night, consulting with the manufacturer regarding the situation. Six of the affected buses were back in service Friday morning.

"The manufacturer has identified both a short-term and a long-term repair, both of which will be covered by warranty," said Mercier.

The city will not be responsible for any of the costs associated with the repair, he added.