Locating power steering fluid leaks in the Audi A4 can be one of the more challenging projects that the home mechanic will face. The tight engine compartment can obscure potential leak sources, and many sources of power steering leaks only appear under a load while driving the car. Oil-based dye systems are available now that help pinpoint these leaks by adding a fluorescent dye to the power steering fluid. Under black light, this dye shows up as a bright streak or spot. Now even very small leaks can be located.
Add the oil-based dye, supplied in the kit, to the power steering reservoir. The reservoir for the Audi A4 is located on the driver's side inner fender well, just in front of the windshield reservoir. Test-drive the vehicle for 10 minutes to circulate the dye and load the power steering system. This will force small leaks to show up.
Use the black light, supplied in the kit, to search under the hood for leaks. Start at the power steering reservoir, following both the small return hose and the larger supply hose to the power steering pump and the rack and pinion steering gear. Note any leaks found.
Raise and support the vehicle using the floor jack and jack stands. Then, from underneath, inspect the power steering rack and the power steering hoses. Note any leaks found.
