Dear Tom and Ray:
While cleaning out my 70-something parents' garage, I found three mostly empty containers of power steering fluid. They are possibly from different decades. Can these be combined, or will mixing them cause serious automotive, health and/or environmental damage? Thanks. — Greg
Tom: They can be mixed for the purpose of making them easier to carry to a recycling facility, Greg.
Ray: I can tell that you want to mix them up and use them in your car, but that's a bad idea.
Tom: Throughout the years, power steering fluid has changed. And different manufacturers have sometimes had different requirements for their fluids. So, it might be compatible with what you need, or it might not be.
Ray: And wouldn't you be annoyed if, to save $5 on a quart of power steering fluid, you ruined your power steering pump and had to shell out hundreds of dollars for a new one? Or worse, you ruined your steering rack, which cost you $1,000?
Tom: Mixing them together will not cause any dangerous chemical reaction or caustic fumes. You'd be in greater danger of that from sitting next to my brother after lunch.
Ray: And there's no environmental danger as long as all the stuff ends up in some kind of container and gets properly recycled.
Tom: If you take the stuff to any service station that does oil changes, they'll probably be happy to take it from you and dump it in their hazardous waste collection bin, along with their used motor oil, transmission fluid and leftover sweet-and-sour sauce from the local Chinese restaurant. That's exactly where it belongs, Greg. Don't do anything else with it.
(Car Talk is a nationally syndicated column by automotive experts (and brothers) Tom and Ray Magliozzi. Write to them at the Car Talk website.)