Synthetic switch best at 6,000 miles

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By Junior Damato MOTOR MATTERS

Dear Doctor: I just purchased a new Scion xB and would like to know at what mileage to switch over to synthetic oil and at what mileage is the engine considered broken-in? - Thomas

Dear Thomas: A safe recommendation to switch to full synthetic oil would be about 6,000 to 7,000 miles. The average break-in period is 3,000 miles, though some vehicles are less.

Dear Doctor: I own a 2007 Honda Accord with the four-cylinder engine and automatic transmission and only 10,000 miles. Since new, I have had an intermittent no-start condition. Sometimes when I turn the key to start, nothing happens and there is no sound from the starter. After a few attempts of turning the key off and to start, it finally turns over. The dealer cannot duplicate the no-start condition. Can you give me any advice? - Mike

Dear Mike: I recommend using a shop 194 bulb hooked up in the socket to the "s" terminal on the starter motor and tied off in view of you. This is a simple and inexpensive way to test for 12 volts at the starter when you turn the key. If there is power in the 12 volts, but no sound from the starter, then the starter is most likely the problem. If there is no voltage power, then do a simple inspection starting at the ignition switch to the final point at the starter.

Dear Doctor: I own a 1995 Toyota Tercel with 110,000 miles. The engine will not start cold unless I use starting fluid. I have replaced all the tune-up parts, including ignition coils and coolant sensor. Do you have any suggestions? - Frank

Dear Frank: The first step is to check for trouble fault codes and the fuel pressure. Though there are no Technical Service Bulletins issued on your car, it sounds to me like a lack of fuel.

Dear Doctor: I own a 2002 Volkswagen Beetle. I would like to verify that the engine in the car is still the original factory engine. Is there an identification number on the engine? - Fran

Dear Fran: The ID will be located on the engine block. Check with the VW dealer for its location and to check that it matches the VIN to the car.

Dear Doctor: I am considering buying a 2002 Isuzu Rodeo that is in good condition. What are your thoughts on this vehicle? - G

Dear G: At this point in time, I will only recommend the purchase of heavy-duty Isuzu vehicles. Parts for used light-duty Isuzu products are getting harder to come by and are expensive.

Dear Doctor: I own a 1988 Lincoln Mark VII. The RPM needle works fine until I put the lights on - and then the needle goes to zero. When I put the lights out, the gauge reads correctly. What is going one? - Giovanni

Dear Giovanni: All of the fuses and the dash cluster ground need to be checked. If both the fuses and ground connections are good, then there may be a problem in the dash cluster itself.

Dear Doctor: Currently, I have only 14,550 miles on my 1999 sedan. I drive less than 400 miles a month. Is it necessary to change the oil and filter every three months? The oil when checked is still clean. - Roy

Dear Roy: Yes, you can go longer than the recommended three months based on your driving habits. Twice a year will work fine. Just make sure when you drive to get the car up to operation temperatures. Another suggestion is to switch to full synthetic oil.

Dear Doctor: I own a 2004 Buick LeSabre with 76,000 miles. When accelerating 40 to 60 mph or going up hills, the car feels like I am driving over rumble strips. The other problem is the gas mileage has dropped significantly. What can you suggest? - Lorraine

Dear Lorraine: The rubble strip feeling you experience can be from a secondary ignition break down, spark plugs, plug wires or the ignition coil. In some cases, low fuel pressure or lazy oxygen sensors can also be part of the problem.

Dear Doctor: I own a 1994 Toyota Camry with 130,000 miles. The engine sometimes stalls when coming to a stop with the engine warm. I have spent over $800 in parts replacement and a tune-up and still have this stalling problem. Can you help? - Anthony

Dear Anthony: A basic starting point is to check for trouble fault codes. I looked on our Identifix site and came up with a common fault. A lazy EGR valve will cause the stalling condition you describe. Have the technician simply disconnect the vacuum hose going to the EGR valve and test-drive the car for a few days to a week and see if the stalling problem is gone. If it is gone, then a new EGR valve may be all that is needed.

•Junior Damato is an ASE-certified master technician. E-mail questions to info@motormatters.biz. Mail questions to Auto Doctor, 3 Court Circle, Lakeville, MA 02347. Listen to Junior online at www.1460wxbr.com Saturdays from 7 a.m. to 10 a.m.

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