This weekly feature for Warranty Direct about car repair and maintenance is written by Tom Torbjornsen, the popular host of America’s Car Show on satellite radio. Below are some recent Q&A from the America’s Car Show email bag.

Dear Tom,
I have heard both pros and cons concerning the need for Motorvac service. Please set the record straight. I have a 2003 Chevy Trailblazer with 35,000 miles. It runs fine. Do I really need this expensive service?
Joe from Colorado

Joe,
Carbon buildup in the upper regions of the engine is a fact of life. It’s just the nature of the beast. Varnish deposits from gasoline build up in the fuel delivery system, as well as carbon in the engine (a byproduct of combustion). The varnish inhibits the flow of fuel through the injectors, and the carbon buildup decreases the efficiency of the fuel-burning process. The sensors in the performance system read these changes and the system responds by constantly making adjustments. Regular Motorvac service (every 35-40 thousand miles) prevents these problems. The engine will start crisply on cold mornings, and you will continue to experience snappy acceleration as the car ages, as well as maintain optimal performance and fuel economy. I highly recommend this service.
Tom

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Dear Tom,
I own a ‘9191 Chrysler Imperial with a computerized dash, and I need an instrument cluster. I priced new ones and they are very expensive (about $500). I can’t find any in the junkyard locally. Do you have any suggestions?
Marla from Spartanburg, NC

Marla,
A few years ago I ran across a company that is of great help in this arena: www.mrwhizard.com. They repair/rebuild digital instrument clusters for a fraction of the cost of a new one. Most rebuilt units cost $189. I followed up with the owner and interviewed him on my national radio show. They are legit and do great work. Success to you.
Tom

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Dear Tom,
I own a 2000 Volkswagen Passat 2.2 Turbo, with 140,000 miles. The transmission fluid is dark brown, but has no burnt odor or visible particles. How often should I change the transmission fluid in this vehicle? Also, would you happen to know why changing the fluid in a high mileage transmission would cause it to fail?
Ed from Saskatchewan, Canada

Ed,
A dark brown color is an indication that the fluid is burnt. Not good. I would probably just change the filter and re-fill the pan rather than do a complete flush. When a transmission has been overheated, the glue on the back of the internal clutches crystallizes. When a complete flush is performed, the detergent in the new fluid removes the hardened glue from the back of the clutches, separating the friction material from their steel backings and rendering the transmission useless. I have seen this happen time after time. The filter change and pan refill will not affect the unit like a complete fluid exchange. However, it’s your tech’s call. Good luck.
Tom

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Dear Tom,
Help! My car (a 2001 Olds Intrigue) started getting hot and all the cheap fixes have not worked. I installed a new temperature gauge, flushed the radiator, replaced the sending unit, and checked for an air lock. It even failed the “sniffer” test for a cracked head. I’ve heard others with this make and year have had the same problem. Were their any recalls? What else do you think I should do? Thanks
Barb from San Francisco, CA

Barb,
I’m not sure what you mean by the “sniffer test.” Perhaps a four gas analyzer? This procedure will only reveal if there are excessive tailpipe emissions; it will not tell you if there is water in the exhaust. These cars are notorious for intake and head gasket leaks, especially if the car is equipped with Dexcool from the factory. Try a cooling system pressure test to force a leak at the weakest point in the system, which reveals the source of the leak. If you find a pressure loss with no evidence of an external leak, perform a block test. During this test, the tech draws a vial of coolant from the radiator and mixes it with a special chemical to see if it turns color. If it does, that means there is exhaust gas in the cooling system and the engine has a blown head gasket. Another way to track down a coolant leak is to perform a cylinder-leak-down-test. During this test, air pressure is fed into each cylinder and the engine is inspected for pressure loss. If pressure is bleeding into the radiator, then the leak is a head gasket. Finally, a dye test could be performed. During this test the tech will add a fluorescent dye to the coolant, then he will run the engine. Next he will shine an ultraviolet light on the engine, and wherever there is a bright yellow color, there is a leak. Yellow droplets in the exhaust stream indicate a blown head gasket. Success to you.
Tom

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Dear Tom,
I will be purchasing a pre-owned BMW 2001 740il or a BMW 2002 745 with approximately 70k or higher mileage. Is that a good purchase? Where do I find a BMW technician in my area to accompany me to the dealer? Thanks.
VW from Miami

VW,
Miami is a great car town with several BMW dealerships and import repair facilities to choose from. I would ask the seller if you could take the car to your garage for a pre-purchase inspection. If they refuse your request, find another car. As for whether or not it is a good purchase? Without seeing the vehicle it is impossible to say. Overall, BMW is a great product both in performance and initial quality, but used conditions can vary depending on how well the vehicle was maintained. A good pre-purchase inspection will reveal all areas of concern. Best to you.
Tom

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‘Til next time…Keep Rollin’

For more articles by Tom Torbjornsen, visit AMERICA’S CAR SHOW web site: www.americascarshow.com

Tom Torbjornsen is an automotive expert of 37 years. An automotive journalist in good standing with the IMPA (International Motor Press Association), Torbjornsen is the Repair and Maintenance Editor for AOL Autos, At Home Portals, and many other websites. Hear his radio show AMERICA’S CAR SHOW, on the Sirius XM Satellite Radio Channel – Stars Too – Sirius 108 and XM 139; Sunday nights – 10PM – Mid EST. You can hear the live stream of the show at www.americascarshow.com Saturdays at Noon EST. Send your car questions to his website at: www.americascarshow.com.

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Filed under: Americas Car Show, Auto News, Buying a Car, Car News, Consumer Affairs, Maintenance, Vehicle Inspections, Vehicle Maintenance, Vehicle reliability, Vehicle repairs, Warranty Direct

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