Automania/Repair & Maintenance

AUTO QUESTIONS AND ANSWER FOR WEEK 14

by Bob Hagin

Q. I have a 1994 Ford Thunderbird LX, with an automatic transmission and 75,000 miles on the odometer. Lately, while driving at a steady pace, I've noticed that it will jerk and feel like it's slipping back into a lower gear. The RPMs jump up before it settles back to where it should be. The whole thing lasts maybe two to four seconds and seems to come and go from nowhere. It feels like it is dropping into a lower gear most of the time, but it occasionally disengages entirely and there is no power going to the wheels at all. Am I about to pay big bucks for a transmission overhaul? N.M. Zephyrhills, FL

A. Have a couple of things checked out before you hit the panic button - but don't wait too long. Have an automatic transmission expert (either at a dealer's shop or an independent) drop the transmission pan and capture the automatic transmission fluid (ATF). Carefully drain the residual AFT off the pan and inspect the solids that are left. There's always a little "stuff" left behind, but great lumps of it are bad. Draw a magnet through the stuff and if iron "dust" is present, it means that the ferrous parts (bearings, etc.) are coming apart. This is also a bad thing. Have the transmission serviced if the technician thinks it's salvageable and run it for a while. My opinion is that you do, indeed, have an expensive problem. Most auto makers say that their automatic transmissions don't need frequent servicing, but most transmissions specialists say that the should be serviced every two or three years depending on how hard they're used.

Q. I have a 1989 Chrysler New Yorker that I bought new. It has a 3.0 liter V6 engine with an automatic transmission and 52,000 miles. The problem is that the radiator fan often keeps running when the engine is turned off. One time it ran for over an hour and then when I started the engine, the fan shut off. It just started doing this in the past six months, and it doesn't do this all the time. Two times I had to unplug it and then plug it in again. D.B. San Bernardino, CA

A. Electric cooling fans on modern cars are thermostatically controlled and if the liquid in the cooling system is above a predetermined temperature, the fan will stay on even when the engine is shut off. By staying on, it continues to drop the temperature of the coolant in the radiator and the difference between the heavier density of the cooler liquid in the radiator and lighter coolant in the hot engine forces the liquid to continue to circulate. This drops the temperature of the engine and helps to keep it from "cooking," as the metal parts of the engine absorb heat. Some vintage cars like the Ford Model T has no water pump and this "thermosyphon" action was the only means of recirculating the coolant. I suspect that the thermostatic switch or relay in your Chrysler needs replacing or that the engine is overheating. Have the temperature gauge and the fan electrics checked.

Q. The gas gauge is broken on my 1987 Mercury Grand Marquis, so I took it to the Mercury dealer and was told that it could cost me as much as $200 to fix. The needle sticks on empty and the gauge light is constantly on when I'm driving. I'm a widow on a fixed income. Do you think it could be done cheaper? What do they need to do? J.H. Virginia Beach, VA

A. Occasionally, I teach a class to females that I call "Living Single With Your Car." The first thing I tell students to do is to query their friends to find an independent shop that's honest and reasonable. Your gauge problem could be as simple as a loose wire, or as complex as an open circuit in the dashboard electrics, but be ready to pay for a diagnosis. You could drive a specific number of miles between fill-ups and hope you don't forget but that's hard on the nerves.