Dear Doctor: A couple of weeks ago I put the key in the ignition and I could not turn the key. I called for road service and the serviceman used a small piece of wire and banged around the key cylinder. The key then turned. I took the Sonata to the dealer but he could do nothing because the problem has not happened since. Do you think this will be a recurring problem? Jerome
Dear Jerome: It’s hard to say. The most common problem with key cylinders that stay locked is sticking tumblers inside the cylinder. The tumblers in the cylinder are what the key grooves push against to allow the key to unlock the cylinder. We use a product called Lock Ease to lube the ignition cylinders, as well as door and trunk key cylinders. Never use oil in a key cylinder. The other possibility is the ignition key could be worn. If you have a second key compare them and or buy a replacement key.
Dear Doctor: I own a very low mileage 1997 Cadillac (only 77,000 miles) that has a blown head gasket. The car has been sitting since April 2006. I like the car and it is in very good condition. I understand it will cost up to $5,000 to repair the engine. Do you think I should get it fixed? Shirley
Dear Shirley: At this point the Cadillac has been sitting for more than two years. If it’s been outside then there may be a lot of rust buildup on brake rotors, the brakes and gas lines. The GM Northstar engine in your car is prone to head and head gasket failure, as well as oil leaks. I would not recommend replacing the heads or head gaskets. Since the car is in excellent condition my only recommendation would be a complete new engine from GM. I have replaced many engines with new ones from GM with great success. You have to remember the actual cash value of your car is not a lot of money. Install a new engine only if the car is as good as you claim and you plan on keeping it for at least three more years.
Dear Doctor: I own a 1995 Ford Explorer 4×4. The problem is when the truck is cold the engine shuts off after driving a half mile when I come to a stop. The engine will restart but will shake and shut off again. I have replaced the fuel pump and mass air flow sensor and all tune-up parts. The gas pedal is also harder than it should be to push down. Any ideas would be appreciated. George
Dear George: Let’s first start with the hard to press gas pedal to see if the problem is the gas pedal cable or throttle body. Then check for trouble fault codes and do a fuel pressure test. The next step is to monitor engine sensors and compare the readings to known accurate readings. The engine shake indicates one or more cylinders not firing properly. I have found leaking vacuum lines, intake gaskets, the EGR valve DPFE sensor and dirty fuel injectors to be common faults. I also looked on the Identifix web site and found there are many cases to confirm my findings. A good technician will know how to properly troubleshoot the problem.
Dear Doctor: I own a 1992 Chevy S-10 pickup truck with only 72,000 hot sunny Arizona miles on it. The windshield wipers start and shut off by themselves. Then sometimes I have to help them get started. My other problem is the speedometer has stopped working, but the technician said the speedometer sender is working. Any ideas? Henri
Dear Henri: The windshield wiper circuit board has been a problem for many years, causing the motor to come on when the ignition key is turned on. Before replacing any parts always check power and ground connections, not to mention the trouble flow chart at Alldata.com. As for the speedometer problem, check it with a good scan tool to monitor the speed signal that goes from the transmission via the computer to the speedometer. I have replaced a lot of speedometer clusters. You can check with the local salvage yards in your area. You will be stuck with whatever the mileage is on the used speedometer if you go the junk yard route. The other option is to send your speedometer out to a factory Delco service center for repair, via any GM dealer parts department.
Junior Damato is an ASE-certified Master Technician.
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Copyright, Motor Matters, 2009