Used car problems have consistently ranked in the top ten complaint categories handled by COMBAT during the past 33 years. There are good deals out there, but there are also hidden, potentially expensive risks that may lurk under the floorboards. When shopping for a “previously owned” vehicle, take heed of what COMBAT clients have experienced.

The Chameleon: Jacquie Thurston of Unity bought a spiffy red “formerly owned” convertible. But when her car door was scraped by a shopping cart she was amazed that there appeared to be a green car underneath. The color difference could have indicated a replaced door after minor damage, or worse, extensive bodywork after a major accident.

Before you purchase a used car, check the entire body for signs of repair, filling materials, or repainting. Check the wheel wells and undercarriage for fresh paint applied to mask rust or damage. Check under weatherstripping, body moldings, dealer emblems and other areas where repainting is more easily detected. A car involved in an accident has a reduced value.

In Thurston’s case, the repainting was cosmetic and the car was fine.

The Puzzle Car: Sometimes insurance companies “total” vehicles and the wrecks are hauled off to be sold for parts, but enterprising mechanics will find similar models that have been wrecked and fit the pieces of two or more together to make a “puzzle” car. This is both illegal and unsafe because a reassembled car will not be as strong as an original and may have ill-fitting panels, leaks and creaks.

Online services such as Carfax.com can help you identify “salvaged titles” (cars totaled by insurance companies).

Tom Wellington of Madawaska bought one of these pieced-together vehicles, but COMBAT got his money back for him (and the used car dealer was fined).

The StinkySubMobile: Grace Talbot of Guilford was happy as a clam when she drove her used SUV home on a summer day but not so happy the next morning when the windows fogged on the inside and the car smelled like a swamp. When her dash lights started to flicker, wipers worked only part time, and seat controls wouldn’t work, she was just plain angry.

Grace had purchased a vehicle that had served time as a submarine when stolen from the previous owner and driven into a pond. The used car salesman had bought the car from salvage, dried it out and slapped it on his lot. COMBAT got Grace her money back.

Before buying, look for signs of water damage, rust under the carpets, stains, “water line” markings, or live trout in a wet trunk.

The Helluva Deal Car: If a dealer appears way too eager to unload a car by offering an unbelievably low price and too generous terms – watch out. It may be a “problem car” (makes and models with a high incidence of problems and recalls). Check auto histories at www.NHTSA.dot.gov or www.nutzandboltz.org.

Bar Harbor consumer Sally Trenholm bought a 5-year-old car with only 12,000 miles on it (COMBAT found out the car had been in the repair shop more than on the road) and Bill Jackson of Greenville bought a truck owned by six people in seven years – and a heap of problems to boot. Why do you suppose those previous owners dumped it?

Finally, beware of “program” cars. While many consumers think “program cars” are dealer demos, they could also be “fleet” vehicles purchased by a company for employees who used them like NASCAR pace cars that were oiled only sporadically. Always ask exactly what “program” means and about the warranty.

While shopping for a used car, think twice before signing once, and have the vehicle examined by a trusted mechanic or knowledgeable friend. If the dealer won’t let you do this, walk to the next car lot.

Consumer Forum is a collaboration of the Bangor Daily News and Northeast COMBAT (Consumers Of Maine Bringing Action Together), Maine’s membership-funded nonprofit consumer organization. Individual membership $25, business rates start at $125 (0-10 employees). For help and information write: Consumer Forum, Bangor Daily News, PO Box 1329, Bangor 04402-1329.