Undercar components are a magnet for grease and grime. Even cars that have only been on the road for a year or two can be covered in road grime, but after five or more years, maintenance and repairs take hours longer because of all of the grease and grime. It is time to clean up the undercarriage of your vehicle (or your driveway, greasy tools, lawn equipment, etc) with some easy-to-use degreaser from WD-40. You can use WD-40 Specialist Industrial-Strength Degreaser or WD-40 Specialist Machine & Engine Degreaser Foaming Spray to clean up any grimy component. This is particularly helpful when you are working on a vehicle that has a lot of crud built up on the chassis. Grease and grime-covered bolts, nuts, adjusters, and the like make it difficult to perform an otherwise simple task. The best part about these degreasers is that you can spray and wipe the grease away. They definitely work better if you can blast them clean with a high-pressure water hose or power washer, but in a pinch, wiping with a towel works.
These degreasers are safe for most components and won’t degrade rubber, polyurethanes, plastics, glass, or wiring, making them safe to use on just about any greasy component. For heavily soiled components, we found that WD-40 Specialist Machine & Engine Degreaser Foaming Spray works best, as the foaming action helps cut deeper into thick road grime and grease, but it does need a good blast of high-pressure water to really get the job done. WD-40 Specialist Industrial-Strength Degreaser works best on lighter oils and grease that don’t need the power of foam and wiping with a towel works well with this product.
Putting the degreasers to work
We put both products to the test on a transmission case for a Jaguar XKE. The case is aluminum, which is tricky with most degreasers, as harsh chemicals can pit aluminum. This was not an issue with both WD-40 degreasers. We found that the lighter grime wiped away using the WD-40 Specialist Industrial-Strength Degreaser, such as chainsaws, bikes, lawn equipment, and lighter vehicle grease. Thick built-up grease needed a blast of WD-40 Specialist Machine & Engine Degreaser Foaming Spray and then a rinse with a garden hose at pressure.
We are working with a component that is out of the vehicle, which makes it easier to take pictures. These products are safe to use directly on the vehicle.
This transmission is from a 1980s Jaguar and will soon be installed into a 1964 Jaguar XKE. It was removed from the original vehicle about 15 years ago, so this grease is not only old, it has had many years to dry up and really grab hold of the metal. It does not flake off easily. We tried the WD-40 Specialist Industrial-Strength Degreaser first to see how well it can handle the thicker grease. With the straw flipped up, we sprayed it on a small section of the case.
After letting it sit for a few minutes, we used a towel to wipe down the case. The grease came off with ease where it was light, but the thicker grease just smeared around. A spray of pressured water would make it work better.
For the thicker stuff, we switched to the WD-40 Specialist Machine & Engine Degreaser Foaming Spray. This product sprays on and foams up immediately to provide maximum coverage and breakdown of grease.
We sprayed the heavily soiled areas with the foaming degreaser. This product does not have a straw. Then we let the degreaser work for about 10 minutes.
Next, we used a shop rag to wipe off the grease. It definitely worked, but it was still harder to get the thick grease off.
We finished the job with a blast from a garden hose with a pressure nozzle. This did the trick and removed nearly all of the grease. If we wanted it perfect, another round of foaming degreaser should get every bit of it gone, or we could use a pressure washer.
WD-40 Specialist Industrial-Strength Degreaser or WD-40 Specialist Machine & Engine Degreaser Foaming Spray works really well and the flip-up straw helps eliminate waste if you are working in a confined area. We found that using pressurized water makes a big difference on how clean the part gets, but if you are working under a car, spraying a bunch of water might not be feasible. Being able to just wipe the parts clean is a big help, and makes WD-40 Specialist Industrial-Strength Degreaser or WD-40 Specialist Machine & Engine Degreaser Foaming Spray very easy to work with.
Check out all the chemical & lubricant products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on using degreaser, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.
A life-long gearhead, Jefferson Bryant spends more time in the shop than anywhere else. His career began in the car audio industry as a shop manager, eventually working his way into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin’, Mopar Muscle, and many more. Jefferson has also written 4 books and produced countless videos. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced.