Engine sludge can be detrimental to your vehicle's performance. Here's the most common causes, the warning signs to watch for, and how to get rid of it.

RAY: First of all, while denatured alcohol is a solvent, we have no idea whether it does anything to remove engine sludge. TOM: Second, we don’t even know if you HAVE excessive engine sludge.

Dear Tom and Ray: Is it safe to add a few capfuls of denatured alcohol to the crankcase of my two older vehicles to remove oil sludge before I change the oil?