I have a '67 Cougar, and every time I wash my car or it rains, the cabin fills with water. A leak seems to be coming from the vent panel forward of the windshield. Any ideas?

Your car has a problem common to early Cougars: rust in the cowl area, either around the duct hole where heater air comes in or where the firewall welds to the cowl on the driver's side (or maybe both). Rain or wash water goes in the vent in front of the windshield and flows to ground on both sides. This also is where air enters the driver's side vent duct. Leaves and other debris get in, hold water and, inevitably, cause rust. On '67 and '68 Cougars, you cannot remove the cowl panel; you have to remove the dash pad and heater ductwork and patch it from the inside. On 1969 and later cars, the cowl panel is removable, making the repair much easier.

The "check engine" light on my 1996 XR7 (V-8) has been coming on. An auto parts store performed a test and found that the code for the error indicated by the light was P1643, which corresponds to a fuel vapor leak. They suggested replacing the gas cap as the first action, which I did. But after disconnecting and reconnecting the battery to reset the computer, the light came back on. What do I do now?

I checked with a former Ford service manager, and he agreed that a fuel vapor leak code likely indicated that the gas cap was not holding pressure, a common problem. Anyway, to completely reset the computer, you have to leave the battery disconnected at least 15 minutes. Then, it will take several drives in the car for the computer to re-learn your driving habits and adjust accordingly. If you fixed the problem, the light should go out and stay out. Your local dealership has a code machine that can reset the computer as well. But if the root cause wasn't corrected, the light will eventually come back on.

I'm doing a transmission swap in my 1968 Cougar (302, C-4 automatic to 3-speed manual). My biggest concern is finding the correct clutch and brake pedal assemblies and clutch linkage. What other years and models of vehicles, such as Mustangs, would have parts that would work on my Cougar? Also, any tips or other information you could provide regarding this swap would be greatly appreciated.

Any small block V-8 (only) Mustang, Fairlane/Torino, Cougar or Montego--or, even, early Mavericks and older Falcons--have the clutch pedal you need. Linkage is usually close and within adjustment range. You also will need the flywheel, starter, clutch pilot bushing, throwout bearing, clutch, pressure plate, transfer lever, all springs and levers, transmission mount, and so forth. You may even need to swap out the drive shaft depending on the transmission you got! Also, you have to remove the steering column to install the new pedal assembly. You will need the shifter and all related levers and bushings for the floor shift so forget any parts car with a column shift. Your console has to be replaced or reconfigured, too--the stick shifter is offset from automatic.

Last night, the headlights went out on my '71 XR-7 coupe. The parking lights and brake lights work. I think the light switch is shot. The car now has 98,000 miles on it and the switch has never been changed, as far as I can tell. Advice?

The most likely culprit for your headlight problem is a defective circuit breaker on the headlight switch itself. These can become intermittent and, often, they fail. You should be able to check it for continuity with a test light. There might also be a problem with the firewall wiring harness connector between engine compartment and underdash area. Also check the wires and connector to the dimmer switch, where moisture can cause corrosion problems. Most likely, the headlight switch itself is good if the parking lights and dash lights work. Remember: If the circuit breaker did trip, that could indicate a serious problem elsewhere in the wiring, so proceed with caution.

My wife owns a 1970 XR-7. We had the carb rebuilt professionally and a full tune-up performed. The car runs and starts great. One problem, though: The exhaust leave a heavy soot mark on the driveway on cold starts. Any ideas?

The engine's probably running overly rich on start-up. This might indicate leaking valve seals, which allow oil into the cylinders after engine shut off. This usually clears up as the engine warms.

—Dick Hertzler