I have a Mercury Villager 2000 van.
In very cold weather, when I start the van and get it out of the garage, the steering doesn’t turn smoothly. It turns in jerks and I have to apply a lot of force to turn it. It doesn’t happen in summers. I consulted the mechanic and he changed the steering lube. Didn’t work. Any ideas?
Or (I must add) if I let the van warmed up first for about 5 minutes, the problem doesn’t occur.
First check that the power steering pump belt is tight and not slipping. Have someone watch the power steering pump pulley from a safe position as you turn the wheel from one side to the other. If the observer sees the pulley stop, the belt is where the problem is located. If this is a serpentine belt, check its condition and tension of the belt.
Usually loss of power assist when the system is cold is a problem with the steering rack piston seal. This usually requires replacement of the rack.
Hope that helps.