QDear Tom and Ray:

My son's 1993 Chevy Caprice Classic is leaking radiator fluid. The cost of an OEM radiator was estimated to be $288, plus two hours of labor. I looked on the Internet and found a seller of OEM radiators that would deliver the radiator for a total cost of $193, including sales tax and a lifetime warranty. I asked the guy at the garage if he would install it. He said yes, but added that if it was from such-and-such a dealer on the Internet, it was a piece of junk. If it is OEM, does it not mean that it was made by Chevy? -- Tim

ARAY: Well, OEM means "original equipment manufacturer." So, it's the same equipment Chevy used when it built the car, whether it was actually made by Chevy or one of Chevy's suppliers. If you're buying an OEM radiator, it should be every bit as good as the OEM radiator your garage will use.

TOM: Just make sure the ad on the Internet doesn't say "OEM-quality" or "OEM-style" radiator. You want an actual OEM product.

RAY: One reason your local mechanic might be reluctant to install a part you bought on the Internet is because you're completely eliminating his markup. Like all other retailers, auto-repair shops buy their stuff at wholesale and sell it at retail, for a profit. He's probably buying the radiator for $193, too.

TOM: But if he's willing to use your part and just charge you his labor rate, that's great. Keep in mind, though, that if the part does turn out to be defective for any reason, you'll have to pay him another two hours of labor to replace it, even if you get another radiator for free.

RAY: One other consideration is whether the place on the Internet is going to be there in three years when you need to use your warranty.

TOM: But if you're willing to take a little risk, and you have a mechanic who's willing to install a part he's not selling you (or you even want to install it yourself), then you can go for it, Tim. And in this case, you can save yourself almost 100 bucks.

Dear Tom and Ray:

I live in Vermont, and I just bought a new Toyota Tacoma. Many of the people in my town tell me that they protect their vehicles from winter salt damage by having their undercarriages sprayed with used motor oil. Apparently, it's legal up here, and it's not terribly expensive. Do you think it's an effective measure to take, and does it do any harm to the vehicle? -- Roger

TOM: As far as we can tell, Roger, this is an old-fashioned remedy that's been passed down in rusty old places in the great frozen North. And like a lot of old folk remedies, it has its roots in truth.

RAY: But it's been surpassed by more effective, environmentally friendly solutions. As you can imagine, in addition to the flood of oil at the application site (unless the guy uses an approved collection system), you drive away dripping the stuff all over the state.

TOM: Given the strict regulations shops face now in disposing of used oil safely, I can't imagine that anyone in charge of environmental regulation or drinking water is going to look kindly on this process. So I'd definitely double-check (or triple-check) the legality of doing this.

RAY: Our recommendation would be to skip the used-motor-oil shower, Roger. If you feel you need more rust protection than the factory provides, I'd ask a mechanic about applying a rust-proofing product designed for that purpose. They cure within hours, provide a much cleaner solution and can be checked and touched up annually, as necessary, without environmental damage.

Got a question about cars? Write to Click and Clack in care of The Post, or e-mail them by visiting the Car Talk Web site at www.cartalk.com.

(c) 2004 by Tom and Ray Magliozzi and Doug Berman