Use one of 5 Keller-Heartt coupons including coupon codes and free shipping deals for April 2020. Today's best deal is a 5% Off coupon code. Use your coupon to save on automotive oil and lubricants at Keller-Heartt. Whether you drive a small car or a big-rig cargo truck, you'll find what you need to keep in in working order here. Shop consumer and industrial oils and lubricants as well as accessories like wiper blades, filters and even oil soaps.