Q: Is it true that 5W-20 oil cannot hold up to the extreme heat of Florida in the summer? My 2001 Honda Civic with 65,000 miles seems fine, but a mechanic with a radio show down here says 5W-30 synthetic is best for cars in Florida. As for me, I think such an oil could cause problems with the oil-operated VTEC system.
I want 200,000 miles from this car. Opinion? By the way, no oil consumption issues.
_Kenneth L.
A: Oh boy. There are a million opinions about this.
For your Civic, Honda recommends the use of 5W-20 motor oil in ambient temperatures between minus 20 and 100 degrees. It's slightly thinner than 5W-30 oil, providing better fuel economy, and it's what your engine was designed to run on.
Also, you're correct: The VTEC (variable valve timing and lift electronic control) is fussy about engine oil being clean and of the right viscosity (thickness), as it uses oil to hydraulically switch between camshaft profiles.
If you were operating the Civic in Death Valley with temperatures above 110, I'd consider using 5W-30 during the summer season. But really, the difference between the two oils isn't significant enough to lose sleep over.
I'd go with premium synthetic 5W-20. That way, at 200,000 miles, your Civic will another 200,000 to go.
Q: All the tires on my 2009 Nissan Sentra (spare included) are properly inflated, but the car's tire pressure warning light remains on. A mechanic said it would cost more than $200 to fix the problem. Is there a cheaper solution?
_Kenneth D.
A: Does your warning indicator simply remain on, or does it blink for a minute after startup and then stay on? A briefly flashing light indicates a system problem, while a steady light indicates one or more tire sensors reporting pressure below 26.5 pounds per square inch.
Keep in mind: Tire pressure changes about 0.8 pounds for each 10 degrees of temperature. Your tires should be checked and set when cold.
The best way to figure out what's really going on is using a pro-grade scan tool to obtain diagnostic trouble codes and to take pressure readings from each tire and wheel sensor.
It's also possible to retrieve codes by grounding a white connector (single blue wire) beneath the driver's side instrument panel and counting the flashes of the tire pressure monitoring system light. Five flashes indicates no faults exist. If a fault does exist, it'll be indicated by a two-digit code. A front-left transmitter battery fault, for example, would be indicated by a code 45; four long flashes followed by five short ones. You would need access to service information to interpret any codes and take appropriate actions. Fault areas include sensor no-data, checksum error, pressure-data error, function-code error, sensor battery low voltage, and a body control module fault.
Since wheel sensors cost about $40-$90 a pop and you'd have to pay for tire removal and installation and diagnostics, the $200 quote doesn't seem out of line.
Sensors can be damaged by careless tire mounting and dismounting methods, driving on a very low or flat tire, or through the use of certain tire sealer products. Sensor battery life is approximately seven years, so that also may be what's up. Renewal of all remaining sensors would make sense during the next tire change.
