Dear Doctor: I own a 2001 Ford F-150 with a 4.2-liter V-6 and automatic transmission. Recently I've been having to add coolant on a regular basis, even though it was driven only around town. When I drove to Ohio from Texas I didn't have to add any. Now that I'm driving it around town I'm back to adding coolant again. A mechanic performed a pressure test and found no leaks. He said the water pump is in good condition. I see no leaks in the passenger compartment. My temperature gauge reads normal. What's up? -- Kevin
Dear Kevin: When an engine uses coolant and there are no apparent leaks, this could indicate internal engine consumption via a leaking cylinder head or head gasket. On your long interstate trip the engine was running at a consistent and even engine speed. Under these conditions, the cooling system is not under the up and down rpm commands, making for an easy ride for the truck. I suggest adding one can of engine coolant stop leak and try it for a couple of weeks and monitor the coolant level.
Dear Doctor: I own a 1997 Toyota Camry 2.2-liter engine with over 132,000 miles. A mechanic tells me I should get it changed transmission fluid changed. I called three places and they all tell me different things. One said I should have it flushed, the second said I should have it drained and the third said I should do nothing. What's your suggestion? -- Richard
Dear Richard: I suggest to remove the drain plug on the bottom of the transmission pan and drain out the fluid. You will only get 3 to 4 quarts out when draining the fluid, so I would recommend this process twice. This will provide you with almost 8 quarts of new factory Toyota transmission fluid.
Dear Doctor: I have a fuel drain back problem on my 1962 Pontiac Tempest. When I start the car daily it's fine, but if I go two days it will turn over for 30 seconds before it starts. Any idea if it could be the fuel pump or a carb float problem? -- John
Dear John: The issue could be linked to an internal carburetor leak down problem. The most common problem if the vehicle is equipped with either a Rochester 2 barrel or Rochester Quadrajet is the leaking small plugs at the middle of the front base under the carburetor. If this is where the leak is located then a simple 2-part epoxy is all that's is needed to stop the leak; simply fill the small cavity where the 2 plugs are located.
Dear Doctor: The key fob on my 2003 Toyota Matrix will not lock/unlock the driver front door. Also, it's not able to lock/unlock from the inside using the button. I can manually lock/unlock from the inside. I can use the key in the door to lock/unlock. The other 3 doors work fine. How can I fix it? -- Chris
Dear Chris: It sounds like there's a problem in the electric door actuator. The technician can simply remove the door panel and check for power and ground at the door lock actuator. This is not a major repair and can be checked by any good ASE-certified technician.
Dear Doctor: I recently stalled out for the first time on my 1999 Honda Accord. The mechanic said I needed a tune-up and a new battery. The next the engine died, but re-started and everything seemed fine. The next day it died and wouldn't move. A mechanic said I needed a fuel pump. Two days later the car died again and the mechanic installed a main relay and ignition switch. Is this normally so difficult to diagnose? -- Borg
Dear Borg: When a vehicle has an intermittent problem the first step is to check for any pending fault codes in the computer. My next step is to check on our Identifix and Alldata web sites for any history and information available. I would also connect a scan tool spark tester and fuel pressure tester to the car and when the engine stalls out I would be able to see what and where are loosing. Ignition switches and main relays are common faults on this car. Electric fuel pump failure is very rare on this car. -- Junior Damato, Motor Matters
Junior Damato is an ASE-certified Master Technician. Email questions to email@example.com. Mail questions to: Auto Doctor, 3 Court Circle, Lakeville, MA 02347