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Buying Used Car: Change All Fluids

By Junior Damato, March 23rd, 2019

strong>Dear Doctor: I'm considering buying a 2008 Lincoln Navigator with 90,000 miles on it. I want to know how to service/recondition it to get the best service and life from this high-mileage vehicle. What is the protocol for fluid changes, oil types, oil, and/or gas additives? Sam

Manufacturer photo: 2008 Lincoln Navigator
Manufacturer photo: 2008 Lincoln Navigator

strong>Dear Sam: First, 90,000 miles is no longer considered high-mileage. Normal servicing I recommend includes brake and power steering fluid, antifreeze, transmission fluid, transfer case fluid, as well as front and rear differential fluids. You should also change the spark plugs and fuel filter (if external). Perform oil changes three times a year if the vehicle is running on conventional oil, twice a year if using synthetic. This is a big workhorse SUV that should bring you years of service. The one problem that will come up in time is the air suspension, if equipped. Swapping to a conventional system is a very good option, compared to paying to repair the air suspension.

strong>Dear Doctor: I have a 2008 Saturn Vue with 53,000 miles with a new starter and new body control module. The key is getting stuck in the ignition and producing no power; I get the key out and shake the computer box lightly on top of the battery and the power comes on. Also, the turn blinkers, radio, and cruise control cut out. My local mechanic and General Motors garage couldn't find anything wrong. What can I do to get this fixed? Virginia

strong>Dear Virginia: We have heard about a lot of problems and some recalls with General Motors faulty ignition switches and key cylinders. The first step is to call a GM dealer with your VIN number and see if there are any open recalls on your Saturn Vue. If not, find a AAA-approved repair shop. A full check of all battery and chassis connections is also needed.

strong>Dear Doctor: I read your recommendation to the owner of the Corvette with the 40-Series tires that are giving him a harsh ride, and that he should change them out from the run-flats over to all-season tires. I own a 1986 Corvette with all-season tires and a new 2019 Corvette with the run-flats. My 2019 'Vette with 32 psi on the run-flats rides smoother than does the 1986 'Vette with all-season and 32 psi. Why am I getting a smoother ride? Nicholas

strong>Dear Nicholas: Older vehicles had suspension systems that were hard-riding, no matter what kind of tire or what kind of pressure was in them. The spring-arm design was all we had back in those days. Today's suspension systems were not yet imagined back the 1980s. I own three Corvettes; the 1971 rides hard and handles poorly compared to the C6 models, including my ZR1. The non-run flat tires demonstrate a major ride difference. It's true that four-year-old tires do stiffen up and will ride harder, as well as lose traction capabilities. At my shops, we remove run-flat tires and swap out to non-run-flat tires weekly.

strong>Dear Doctor: My concern is proper tire air pressure for my 2018 Subaru Forester. I find that service station air pumps are notorious for their inaccuracies. Can you recommend a good, accurate air pressure gauge? Which are more accurate: the dial type, digital, or pencil type gauges? I believe maintaining the recommended tire air pressure to be very important, and so does the government, which has mandated TPMS on all passenger cars. Michael

strong>Dear Michael: There are many tire gauges on the market. I recommend a good digital gauge. A good digital gauge is $20 or less. Do not buy a cheap gauge. I also recommend to change the tire pressure 2 to 3 pounds and perform a tire rotation at every oil change, as this will change the tire footprint to the ground.

strong>Dear Doctor: A couple years ago I was trying to find a new battery for my antique car, a 1926 Packard 243 Touring car. Six-volt batteries are not the easiest to come by, but along the way I found a 6-volt AGM battery with better specs then other 6-volt units. The price was acceptable, though I had to change one of my battery cables to fit, and I needed to find a 6-volt AGM-capable battery charger. The biggest issue, because it takes up much less space, was to prop it up and position it so as not to bounce around. Have you had experience with these type batteries? If so, what is your opinion? Ron

strong>Dear Ron: I would suggest a 6-volt AGM battery and matching charger by Optima. I purchase my Optima products from the Interstate battery call center in Freetown, Mass. You can reach them at 800-753-1590.

Big Drop in Fuel Mileage: Get Engine Test

10/19

Big Drop in Fuel Mileage: Get Engine Test

strong>Dear Doctor: I have a 2014 Ford F-150 with the EcoBoost engine. The dealership cannot tell me why my gas mileage is at 9 mpg. It was 24 mpg when I purchased it. Can you help me out? Gerald

Gas Mileage Misread: Fuel System Needs Attention

10/12

Gas Mileage Misread: Fuel System Needs Attention

strong>Dear Doctor: I own a 2006 Ram 2500. The mileage calculator says I'm getting 30 miles per gallon in fuel economy, but I'm actually getting about 20 mpg. What should I do? Mark

Car Shakes at Idle: Check for Multiple Fault Codes

10/05

Car Shakes at Idle: Check for Multiple Fault Codes

strong>Dear Doctor: My 2009 Toyota Camry with 199,600 miles has a check engine light showing the codes P0101 and P0170. I have already replaced the MAF sensor, PCV valve, throttle body, the car's computer, O2 sensors, cam sensor, crank sensor, fuel pump, injectors, and fuel pressure regulator. I also checked for multiple vacuum or air leaks, and the cabin air filter, spark plugs, alternator, and battery have all been checked over the course of a year. Now the car has both codes showing consistently and it shakes at idle. What should we do? Cheyenne

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