Q. I purchased a mint condition 2001 Lincoln LS with 106,000 miles from a relative. As far as we know it, it always leaked 1 or 2 drops of oil and leaves a mess on the garage floor. I had the Ford dealer look at it and they said that they can’t pinpoint the leak and would have to use a dye and UV light to find it. Repairs on this car are not inexpensive. Could I damage the engine if I used a pour-in stop leak product? My other car is a Chevy and after 22 years still doesn’t leak a drop of anything.
A. Over time the seals in the engine will start to dry up and can leak. The oil additives that claim to stop leaks will cause some swelling of the seals and slow down or stop the leaks. I have never found these additives to cause any harm. What you might try is using “high-mileage” oil; these oils also claim to help prevent small leaks with additives that keep engine seals flexible.
Q. I am a AAA member and enjoy reading your column in the various publication that publish it. I have a question about oil changes that I have not seen addressed anywhere and hope you may be able to provide some guidance. My 2008 Mercury Sable is equipped with an oil sensor that tells me when it is time to change the oil (“5% oil life left”; “3% oil life left”; “1% oil life left”; “change oil NOW”). It used to indicate it was time to change the oil at about 7,500 mile intervals. I retired from work last year and currently put very little mileage on my car (probably less than 6,000 miles per year). Most of it is within the city-type driving or short highway trips. I noticed that the change oil message comes on now even though I have traveled less than 2,000 miles since the last oil change which is usually 5-6 months previous. Does oil degrade over time even though the car is not being driven very much? Should I do as the sensor tells me and have the oil changed even though I have driven less than the manufacturer suggested 7,500 miles since the previous oil change? If I can go longer between changes than what the sensor tells me, is it OK to drive with the message telling me to change oil or should I somehow have it reset (or disconnected) and just keep track of the mileage as to when the oil should be changed? Thanks for any information you can give me with this!
A. The oil change reminder uses a variety parameters not just mileage. The system can look at how often the car starts, length of trip and engine temperatures. Some systems actually measure moisture in the oil. If the engine doesn’t get up to temperature it will actually cause contaminants to stay in the oil. My advice it to follow the oil monitor recommendations.
Q. My daughter would like to have a remote car starter installed in her 2011 Ford Fusion. I have heard that sometimes these starters are great; however, often, they can cause serious problems with other car functions/systems. What is your opinion? My daughter has to be out of the house before 6:00 a.m. every morning for work, so she is really pushing for this.
A. A remote car starter when installed properly will not cause any problems or void any warranties. The problem usually arises from poor electrical connections. Professional installers will never just cut wiring, but will use custom made wiring harnesses to avoid problems. My other advice is to purchase a remote starter from a reputable company that stands behind their work and offers a warranty on both the parts and the installation.
Q. I own a 2002 Cadillac Deville with 20,500 miles on it which has never given me any trouble until a few weeks ago. It now stalls after driving just one eighth of a mile. No trouble lights show on the dash. I can immediately restart it and it will not stall again. I have tried letting the engine idle in the driveway but it can still stall. I brought it to a local mechanic and he cleaned the throttle body and reset the idle. He kept it over night to test it in the morning, only to find the same problem for which he had no answer. Any advice that you can offer would be appreciated.
A. One problem that is possible is a poor ground to the computer and sensors. I have seen this as a problem with this model on several occasions. Check the bolts in the fuse box as well as the grounds near the thermostat. A poor ground can cause just this problem.
Q. I just purchased a 1999 Jeep Grand Cherokee Limited with 4.7 V8 and dual climate control. Am fixing it up slowly and tops on the list is lack of heat. The fan blower and A/C work fine. Research on internet indicates problem is likely the blend doors. Pressing the buttons brings up codes 54 and 56. I considered buying doors on line and doing it myself, should I?
A. This system uses electric motors to actuate all mode doors. The temperature/blend-air door for all models is actuated by an electric motor. On some systems there are two doors and actuators to allow the driver and passenger to have individual temperature control. It can take up to three hours to complete the repair. Although there is nothing complicated about the work, you will need a certain amount of patience and do have to be a little fussy reassembly. I would also suggest taking photos as you do the repair to get the reassembly correct. If you don’t have half a day of uninterrupted time I would leave the repair to a professional.John Paul, the “Car Doctor,” is public affairs manager for AAA Southern New England and a columnist for Boston.com. A certified master technician, Paul tests dozens of new cars each year and also hosts a radio show on 950 WROL in Boston (www.wrolradio.com) on Saturday mornings at 9. Need car advice? E-mail John at firstname.lastname@example.org or go to www.boston.com/cardoctor for past columns, tips, and repair help.