* Air in the system: This is the most common cause. Air gets into the system through leaks, a low fluid level, or a faulty power steering pump. The pump agitates the fluid, causing it to foam. Look for leaks around the pump, hoses, and steering rack.
* Contaminated fluid: Water contamination (from a leak) or other contaminants can cause foaming. Water can emulsify with the fluid, creating a frothy mixture.
* Worn-out power steering pump: A failing power steering pump can draw in air more readily, leading to foaming. You may also hear unusual noises from the pump (whining, groaning).
* Failing power steering rack: Similar to the pump, a leak in the rack can introduce air into the system.
* Overfilling: While less common, overfilling can also lead to foaming.
What type of fluid to use:
For your 2006 Ford Focus, you should use Mercon V ATF (Automatic Transmission Fluid). Do not use power steering fluid specifically labeled as "power steering fluid" unless it's explicitly stated to be compatible with Mercon V. Using the incorrect fluid can damage seals and components within the power steering system. Check your owner's manual to be absolutely certain, but Mercon V is the generally accepted recommendation.
What to do:
1. Check the fluid level: If it's low, add Mercon V ATF. However, only add a small amount at a time and watch for leaks. Adding too much is also problematic.
2. Inspect for leaks: Carefully examine all hoses, connections, the power steering pump, and the steering rack for any signs of leaks (wetness, fluid drips).
3. If you find a leak: Repair or replace the leaking component immediately. Ignoring a leak will worsen the problem and could lead to complete power steering failure.
4. If no leaks are found and the foaming persists: The power steering pump itself might be failing and may require replacement. You likely need professional help at this point.
Important Note: Driving with foaming power steering fluid is risky. It can lead to power steering failure, making it difficult or impossible to steer, especially at low speeds. Address this issue promptly. If you're not comfortable performing these checks and repairs yourself, take your vehicle to a qualified mechanic.
