I drive an older Lincoln Town Car. It’s old enough to have its own driver’s license. Being fond of the car, I’m on a Facebook page with others more or less obsessed with the vintage auto. (They stopped making them 10 years ago.) Many of those on the page use it for answers when their pride and joy is doing something that befuddles them.
One fellow was upset because the radio on his car kept playing after he turned off the car and opened the door. (The radio will continue 10 minutes after the engine is turned off or until a door is opened, a factory feature.) Also, his doors would not lock. (Another feature is that the doors will not lock from the outside if the key is still in the ignition, preventing the driver from locking themselves out.)
The responses varied from “I’ll take it off your hands for cheap” to dismantling most of the electrical wiring and finding the cause. Many of the cars on the site have been subject to abuse, salty winter roads, flood damage, having been rebuilt from salvage, having been retired from limo service at 450,000 miles, etc., so to have something electrical be “off the wall” is not unusual.
Think it through, one symptom at a time.
The radio stays on until it is turned off or until the car is turned off but will keep playing unless the door is opened after removing the ignition key. OK, it’s acting like it would if the key were still in the ignition.
Second symptom. From outside, the car doors will not lock. These are some of the cars that are “idiot-proofed” to help owners keep from locking their keys inside the car by not allowing the doors to lock if the key remains in the ignition.
My armchair diagnosis was: The car thought the key was still in the ignition switch. I explained my diagnosis to the hapless owner and suggested that he shoot a little lubricant directly into the keyway of the ignition switch, insert and remove the key a few times, and repeat. He did, and it worked, making me his most favorite person that day.
Then there’s the classic, “Doctor, I get a stabbing pain in my eye when I sip my tea” – to which the good doctor answers, “Remove the teaspoon from your cup of tea before you sip your tea and that won’t happen.”
Becoming part of a diagnosis and repair that’s already begun is always fun. It’s like reassembling something that was taken apart in the dark by novices.
The next challenge: a car that had been loaned to a friend had overheated and stopped – in the dark, of course. The owners, on arrival, found the coolant level to be low and guessed that the overflow reservoir was defective. A new generic overflow tank was installed and was filled, as was the radiator. A few minutes later, it overheated and stalled again and was diagnosed as now having destroyed the engine “because when you try to start it, you get this horrible grinding noise coming from the engine.”
A daylight inspection found that one of the two fan belts was broken. One belt ran the power steering and air conditioner, the other the water pump and the alternator. The battery was also (not surprisingly) too discharged to spin the motor.
With the battery charged, the engine turned over fine and started. The “horrible grinding noise” had been the starter trying to turn with a run-down battery. A new belt was installed and coolant added. Aware that overheating can cause a head gasket to fail, the engine was run at idle long enough to completely warm up the cooling system with the radiator cap removed. This was done to watch for air bubbles coming up through the coolant, which is a symptom of a bad head gasket. With neither air nor oil showing up in the coolant, the dipstick was pulled, and it showed no trace of antifreeze in the oil. The car went back into daily service.
The alternator/water pump belt would last a couple of months and break. At the parts house, with the broken belt in hand and making sure the guy behind the counter was “experienced,” we showed him the belt and asked if there was a stronger belt in that same size. He asked, “What’s it on?” and pulled up the vehicle. He came back with a belt the same width and length but was about three times as robust as what had been failing in that application.
Aha! Sometimes there is a reason why what the manufacturer specifies is what’s needed rather than one of the “same size” that’s half the cost.
