You Might Want to Skip That Undercarriage Wash: Here’s Why
It's no secret that Michigan winters can wreak havoc upon our cars.
What Salt Does to Your Car's Undercarriage
Local, county and state road crews are great about getting salt on Michigan's more heavily traveled roadways to help melt away the snow and ice and keep us all safe, but that salt isn't your vehicle's best friend. In fact, the same chemical reactions that allow salt to help clear our roads are the ones that can cause nightmares to your car's undercarriage.
Two car parts that are especially susceptible to corrosion and rust are the brake and fuel lines. That’s because they’re close to the undercarriage of the car, which takes the brunt of the road salt damage. - Erie Insurance
In most cases, it's a good idea to wash your car thoroughly (including underneath) after it's been exposed to salted roads. This will minimize the potential impact of corrosion and rust.
When Not to Spring for the Undercarriage Wash
If you drive a used car, and you're not sure whether the previous owner(s) took care of the underside, be sure to check with your mechanic to verify the condition of your car's undercarriage. It's quite possible that the spray of an undercarriage wash could be at a high enough pressure to do even more damage to your car.
I learned about this the hard way. Unbeknownst to me, the transmission oil pan on my used vehicle was nearly rusted through. The high pressure of a well-intentioned undercarriage wash proved to be the proverbial straw that broke the camel's back, and caused all my transmission fluid to leak out during an out-of-state trip over the holidays. When all your transmission fluid leaks out, your transmission ceases to function properly. Luckily I was within 10 miles of my destination when second gear became my only usable one, and my mechanically-inclined brother knew just what to do. It could have been a lot worse.
Moral of the story - your car might not be in the condition to handle an undercarriage wash. Your mechanic can let you know whether your car's able to handle it, or whether other repairs are recommended first.