If your vehicle is showing red or brown fluid leaking under the front of the car, here are the most likely causes and the parts you'll need to fix each one.
Engine oil is amber when new but quickly turns brown or black. Valve cover gaskets, oil pan gaskets, and front main seals frequently degrade and seep oil under the front of the vehicle.
Power steering fluid is typically red, but turns brown as it ages. Leaks from the high-pressure hose, return hose, or the pump itself are highly common and will drip under the engine bay.
If the car recently had an oil change, a loose oil drain plug, missing drain plug gasket, or a double-gasketed oil filter will cause a rapid brown fluid leak.
Automatic transmission fluid (ATF) is red and turns brown over time. The cooler lines running to the radiator at the very front of the car are prone to rusting, rubbing, and leaking.
Many modern vehicles use red, pink, or orange long-life coolant. A failing water pump, cracked radiator, or leaking hose will leave a puddle of this fluid near the front bumper or engine pulleys.
The transmission pan sits under the vehicle and holds the red/brown ATF. The gasket can fail over time or leak if over-tightened during a recent transmission service.