Cars

What’s causing my car’s burning smell?

John Paul, AAA Northeast's Car Doctor, answers a question from a reader concerned about a burning odor.

AP Photo/Bob Edme, File

Q. I have a 2013 Fiat and I live on top of a steep mountain. Since I moved up there in November, I detect a burning smell when I get out of the car. I don’t smell it when I drive to other places. When I try to drive very slowly up the mountain there is less burning smell. The car gauge never shows that it overheats. I had the car checked out and they couldn’t find anything wrong. Do you have any suggestions? 

A. There are two common areas that cause a burning smell – brakes and fluid leaks. I would start with an inspection of the brakes, looking for uneven wear that could indicate a sticking brake caliper. The second possibility is oil leaking on the hot exhaust. Have a technician add dye to the various fluids, drive up and down your mountain road, and then return to the repair shop for an inspection. The dye will help pinpoint any leaks. 

Advertisement:

Q. I have a 2018 Hyundai Elantra GT that I purchased new. After an oil change at the dealership. the drain plug dislodged and the motor was destroyed at 12,500 miles. The dealership replaced it. At 124,000 miles, it started making the same noise and I immediately turned it off.  The oil light never came on, and there was oil on the bottom of both doors. The replacement engine is now blown. I had the oil changed just over 4,000 miles prior, and I checked the oil myself a week before. It’s not under warranty and too costly to repair. The dealership told me that some cars just use more oil than others and can’t tell me how this happened or how oil got on the doors. Aside from a missing drain plug, what else could cause such a rapid loss of oil? 

A. The oil sender unit could cause a very rapid oil leak and could have been the cause of the failure, although typically the oil light will illuminate. The other common issue is a bearing failure and a possible cracked engine block. I would contact the corporate offices of Hyundai and ask about warranty coverage. Many Hyundai models, due to a class action lawsuit, are covered by a limited lifetime warranty. The one caveat is that the car received regular maintenance. The last possibility is taking Hyundai to court under implied warranty of merchantability (lawyers weigh in). This warranty makes the assumption that a good or product works for its intended purpose. At four years old and 124,000 miles, with proper maintenance, your car should have much more life left in it. 

Advertisement:

Q. My 2011 Lexus hybrid has been draining the car battery over a six-to-eight-hour period. The dealer cannot find or fix this problem. The car runs well and has 170,000 miles on it. Any suggestions?  

A. For the battery to become completely discharged in eight hours there is a significant electrical draw. At this point, the dealer or other repair shop needs to do a test of parasitic draw. Using the correct tools, the technician will be able to monitor the electrical system and measure the electrical current use. Typical/normal parasitic drain is 50-80 milliamperes. Some possible circuits that are not shutting down are the fuel pump (4-8 amps), seat heaters (3 amps), cooling fan (5-7 amps) and even brake lights or a faulty alternator. 

Q. For the first time in decades we now have cars with automatic transmissions. We have a very good mechanic, but he is wary of replacing the automatic transmission fluid and filter. He says the process can dislodge crud and cause problems. Right now, the fluid in both cars is at a steady level and the right color. Any opinions?

A. If the fluid is full, the color looks good, and the fluid has no odd odor, I would not change it unless there is a maintenance requirement in the vehicle owner’s manual. I would vary from this recommendation if you are towing a trailer, using your car for delivery or Uber/Lyft, or if it were stuck in the snow causing you to over rev the transmission. These situations can be hard on the transmission. 

Advertisement:

John Paul is AAA Northeast’s Car Doctor. He has over 40 years of experience in the automotive business and is an ASE-certified master technician. E-mail your car question to [email protected] Listen to Car Doctor on the radio at 10 a.m. every Saturday on 104.9 FM or online at northshore1049.com.

Conversation

This discussion has ended. Please join elsewhere on Boston.com