A Jet Engine Roar Under Hood of SUV is Sign of a Problem

September 26, 2009/Auto Used Car Search

MOTOR MATTERS ASK THE AUTO DOCTOR BY JUNIOR DAMATO

Dear Doctor: My 2003 Chevy TrailBlazer with 60,000 miles sounds like a jet engine under the hood and my gas mileage has dropped to 8-10 mpg around town and has lost power. My dealer said the fan clutch is fine. An SUV that sounds like an 18-wheeler in low gear cannot be normal. Please help me! Amy
Dear Amy: Fan clutch noise and failure go together like a hand and glove. I have replaced many on these type vehicles. A faulty fan will cause a loud roar noises, as well as a drop in gas mileage. I suggest having another shop take a closer look at the coolant clutch fan assembly. Make sure the transmission is upshifting as designed and that the brakes are not staying partly engaged and that they are releasing properly.
Dear Doctor: My friend has a 2006 Buick LaCrosse CXL and had to have the front disc brakes replaced at 11,000 miles — which was covered under warranty. However, these new brakes have gone out again at 17,000 miles. The dealership will not cover them a second time, saying that they are a wear item not covered. I believe he should demand that they fix them and determine why the car is eating brakes at this rate. Neither he nor wife drive hard and ride the brakes. I suggested that he have the dealer install a lifetime guaranteed set of pads this time. What do you think? Dave
Dear Dave: Brakes are considered a wear item, however there is no reason for the rapid wear time on this vehicle. The dealer is under no obligation to offer a lifetime warranty on a wear item. Are the rear brakes contributing to the braking action when the brakes are applied? If the rear brakes are contributing when braking, then I suggest going to a local shop for the top quality name brand brake pad set. Brake pad life will average depending on driving habits and conditions from a low of 15,000 miles to 100,000 miles. I do not recommend rotor resurfacing for rotors that are out of round and cause pulsation. I suggest replacement.
Dear Doctor: I own a 2008 Nissan Altima with the four-cylinder engine and automatic transmission. On several occasions when abruptly hitting the brakes the gearshift slides into neutral. The dealer couldn’t find a problem. What might be causing this to happen? Paula
Dear Paula: There’s a possibility that the transmission linkage is not adjusted properly, which is not locking into the gear. With any type of quick brake action the linkage pops forward into neutral. Another possibility is that there is movement in the engine/transmission mounting. Whatever the fault this must be repaired due to safety reasons.

Dear Doctor: I own a 1998 BMW 740i with 120,000 miles. Sporadically, but now with growing frequency, after turning the ignition to start, the radio does not work and the power steering loses power. The interior overhead dashboard light will go on and I will lose brake lights. What is happening? Wayne
Dear Wayne: I have seen problems such as yours caused by faulty connections and ignition switch failures. This is the first area to look at. There is no set pattern listed on your problem. You can also stop by the local dealer and ask the service writer if they have run into this same complaint.
Dear Doctor: I own a 2003 Toyota Highlander V-6 AWD with 120,000 miles. It’s in good condition with no mechanical difficulties. Although I generally maintain the vehicle, I have neglected the transmission service. The dealer recommended that I change the transmission fluid and filter. I am hesitant because I have heard that a first transmission service at this time will stir up metal filings that may cause transmission problems and fluid leaks. I’d like to keep the SUV for another 30,000 miles. What is your opinion? Jeff
Dear Jeff: I would simply drain the transmission fluid from the drain plug if equipped. If not so equipped then I have no problem with dropping the transmission pan and replacing the fluid and gasket.

Junior Damato is an ASE-certified Master Technician.

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Copyright, Motor Matters, 2009