* April synthetic $6/bbl over WTI, nearly 5-month high
* Syncrude output down, Suncor set for maintenance
* April WCS quoted at $26 under WTI
CALGARY, Alberta, March 4 (Reuters) - Canadian synthetic crude prices strengthened to a near five-month high on Monday on production rates from some of Canada's major oil sands upgrading facilities, market sources said.
Light synthetic for April delivery was quoted at $6 a barrel over benchmark West Texas Intermediate, up $1.25 from Friday, according to Shorcan Energy Brokers. That was its highest premium since October 11.
Canadian Oil Sands Ltd, the largest interest owner at Syncrude Canada Ltd, said production from the mining and synthetic crude processing venture fell 13.5 percent to 240,000 barrels a day in February. That is down from capacity rates of about 350,000 bpd.
Meanwhile, maintenance on a hydrogen plant at Suncor Energy Inc's Northern Alberta oil sands facility is set to start by the end of this month, market sources said. The planned 14-week shutdown will lower output from Upgrader 1, one of two plants that convert mined bitumen into synthetic crude.
The company also expects to start a full shutdown of Upgrader 1 in the second quarter. Lasting seven weeks, the maintenance will curtail the unit's 100,000 bpd of synthetic output.
Heavy crude prices also strengthened on Monday. April Western Canada Select last sold for $26 a barrel under WTI, compared with $28 under on Friday.