Q: My wife's Camry is making a humming noise when in motion, not impacted by wheel turns or by brake application. It gets louder as you go faster. I have a feeling that I know what it is, but would appreciate another opinion.
A: Is this a setup? If you think you know, why not share it? So, to make sure I'm unlikely to miss, I'd suspect — in this order — tire noise, wheel bearing howl, air leak buzz around windshield or doors, serpentine belt/idler pulley/alternator or power steering pump whine, torque converter drone, transaxle/differential bearing howl, RF static from the audio system and last but not least, happy in-laws humming Christmas carols in the back seat!
Q: We found a 2009 Honda Odyssey that had 14,000 miles on it. The previous owner had four cars and the van wasn't used much so he decided to sell it. The Carfax was clean and it's in excellent shape. We will probably put about 15K to 20K miles a year on it, meaning it will be driven more in the next 12 months than it was in its first four years. Would this van be a candidate for synthetic motor oil? The Honda onboard oil life monitoring system seems to be recommending changes at about 7,500 miles or so.
A: Yes, absolutely. In my opinion, virtually every automotive engine is a candidate for synthetic oil. Synthetics offer better performance over a wider range of operating temperatures and better viscosity stability over its service life. These benefits are small and the higher cost of synthetics is a very, very small increment of the overall cost of ownership, operation, maintenance and repair over the life of the vehicle. To me, that makes the decision to use synthetic lubricants an easy one.
But I'd be hard-pressed to go more than roughly 5,000 miles between oil changes. Call me old-fashioned, but I'm just not comfortable with longer intervals for my personal vehicles.
Q: I drive a 2002 Honda CRV with 97,000 miles on it. A "Check engine" light diagnostic indicated an oxygen sensor heater was working intermittently and the recommendation was to replace the "b1s1o2." Neither an independent auto shop nor a Honda dealer could really explain why I should spend $500 ($350 parts, $150 labor) if the only issue is slightly decreased gas mileage. I drive less than 4,000 miles a year and 99% is city driving so my mileage hasn't been great. What is the worst downside of doing nothing and what would you recommend?
A: Honda recommends inspecting/cleaning/repairing any faults in the connectors, harness or circuit from the ECM to the "bank 1, sensor 1, oxygen" — the front oxygen sensor. Then have the DTC fault code cleared. If it comes back, I'd replace the O2 sensor. My ALLDATA database confirmed the cost for the OE sensor at over $350, but a quick Internet search found reputable brand name replacement sensors for your vehicle in the $50-$150 range. These units require harness splicing, but are significantly less expensive. Installation should take about 30 minutes.
The function of the electrical heater is to stabilize the sensor's operating temperature, allowing the engine management system to read and adjust the air/fuel ratio more accurately. This reduces the burden on the catalytic converter — an even more expensive component — and optimizes engine performance and economy.
Your question is valid. Since the sensor is heated by the exhaust it still may be supplying A/F ratio data, but because it triggered a fault code the data may not be accurate or the ECM may be substituting a default value, meaning less efficient operation and potentially more unburned fuel for the converter to catalyze.