Spring isolators greatly help your vehicle coil spring, to support the weight of your vehicle and to reduce noise. Coil spring isolators are used on vehicles with a MacPherson strut that is typically found on most front-wheel-drives. In every strut suspension, there are two coil spring isolators used. The so-called lower isolator is positioned between the coil spring and the spring seat on the strut, while the other is located between the coil spring and the top mount. They are used to prevent metal-to-metal contact between the spring and the strut, or mount and to reduce rolling noise.