Q: I own a 1997 Ford Crown Victoria. I recently noticed that the engine was leaking antifreeze. I took my car in for service, and I was totally surprised when they told me that my engine’s plastic intake manifold was cracked and needed replacement. They also told me that this is a common problem with the 4.6-liter V-8 engine. The repairs were very expensive, and I’m wondering what the benefits are of having a plastic intake manifold. Also, do you know if other manufacturers are having trouble with their plastic intake manifolds? -- S.G., Orland Park

A: S.G., unfortunately, Ford did have a problem with the plastic intake manifolds on the 4.6-liter V-8 (2-valve) engines. Ford issued a technical service bulletin (#02-2-2), which details the problem as a cracked coolant crossover.

The bulletin also lists the appropriate service kits for the various models with this engine. The advantages of using plastic over aluminum include less weight, smoother interior finish (translates to better airflow), and of course, cheaper to manufacture. Like any engine featuring components made from different materials, expansion and contraction during heating and cooling cycles pose potential sealing problems as the different materials expand and contract at different rates.

To answer your last question, yes, there are other manufacturers experiencing troubles with their plastic intake manifolds.

Q: I’m trying to replace the oxygen sensor in my 1993 Chevrolet Lumina. I bought a new sensor at the local auto parts store, and they told me that it’s a fairly easy process to replace it. They said it’s like changing a spark plug. I cut the old wiring connector off so I could use a six-point socket on the old sensor, but it won’t budge. I don’t want to break it off in the exhaust pipe. What do you recommend? -- C.I., Bridgeview

A: C.I., if you’re familiar with a torch, you’ll want to heat up the pipe around the area where the oxygen sensor screws in. If you’re not familiar with a torch, take your Lumina to a muffler shop and have them do it for you. If you try to force the old sensor out, you might break it, leaving part of it inside the pipe. The other thing that could happen from forcing the old sensor out is that it might damage the exhaust pipe’s internal threads. Neither one of those scenarios is appealing.

Q: I own a 2007 Toyota Sienna. The driver’s side power window is making a clicking noise at times during operation. I had it looked at, and the technician couldn’t find anything wrong. He took the door panel off and said everything looked okay. The noise seems to be getting louder. What can I do? -- J.P., Matteson

A: J.P., get a second opinion. Also, Toyota did issue a technical service bulletin (# NV013-07), which mentions that the problem could be due to loose or missing window regulator bolts. The bulletin also lists part numbers for new window regulator bolts.

AutoAdviser: Ira Siegel is an Automotive Instructor and ASE Certified Master Auto Technician. If you have auto-related questions for Ira Siegel you can call and leave your questions at the Auto Adviser Hotline at 708-633-6839 or e-mail a question to Autoadvisr@aol.com.