Dec 27 (Reuters) - U.S. oil refiners on Tuesday were working feverishly to resume operations at a dozen facilities knocked offline by a holiday deep freeze, a recovery that in some cases will stretch into January.

An Arctic blast sent temperatures well below freezing and led to power, instrumentation and steam losses at facilities along the U.S. Gulf Coast. The affected plants process about 3.58 million barrels of oil per day, delivering about 20% of U.S. motor fuels.

Refiners have been running near full capacity with strong prices for diesel and other fuels. Retail gasoline prices ticked up along the Gulf Coast this week, but nationwide prices have not been affected by the temporary outages.

Most of the affected plants suffered minor damage. Temperatures fell as low as 17 degrees Fahrenheit (minus 8C) along the Gulf Coast - freezing some instruments and overwhelming steam and co-generation units at several facilities, according to people familiar with the matter.

Two Houston-area plants - Motiva Enterprises' Port Arthur and Petroleos Mexicanos' Deer Park complexes - have restarts that will take them into the first or second week of January, according to notices filed with the state and people familiar with operations. Spokespeople did not reply to requests for comment.

"We'll be up and running in about two weeks," barring any startup disruptions, according to one person involved in the restarts. "This freeze event was a lot lighter than the February (2021) freeze so I'd expect a quick recovery."

Over the weekend, TotalEnergies began working to regain a steam and power co-generation unit critical to sustaining operations at its Port Arthur plant. Exxon Mobil was close to returning its Beaumont, Texas, plant to full operation on Tuesday. Spokespeople for the two did not reply to requests for comment.

LyondellBasell Industries was in the early stages of resuming production at its Houston refinery, people familiar with plant operations said. A spokesperson did not reply to a request for comment.

Marathon Petroleum, which operates the second-largest Gulf Coast facility after Motiva, aims to get production back by week's end, the people said. Marathon declined to comment.

Valero Energy, which suffered disruptions at three of its Texas refineries, did not reply to requests for comment. It was in the process of restarting its Port Arthur plant over the weekend, people familiar with the matter said. (Reporting by Erwin Seba, additional reporting by Gary McWilliams; Editing by Howard Goller)