Monthly Archives: July 2016

You Need for Change Your Oil Every 3,000 Miles

unduhan-12No, you don’t, according to every auto manufacturer we’ve talked to. The main advocates of the 3,000-mile oil change schedule are those who would profit by it: repair facilities, quick-lube chains and service departments at some new-car dealers.

Years ago it was a good idea to change the oil and filter frequently, but because of advances in engine materials and tighter tolerances, as well as the oil that goes into engines, most manufacturers recommend intervals of 7,500 miles or more.

Ford, Volkswagen and Porsche, for example, recommend oil changes every 10,000 miles. So does Toyota on several engines, including the Prius’ 1.8-liter four-cylinder and the Camry’s 2.5-liter four-cylinder. BMW says owners can go up to 15,000 miles between oil changes (with synthetic oil).

Manufacturers suggest you change oil more often for “severe” driving conditions, such as frequent trailer towing, extensive stop-go driving or idling in traffic, driving in extreme heat or cold, or frequent short-distance driving in which the engine doesn’t reach full operating temperature.

Some car companies, Ford and General Motors among them, equip most vehicles with oil life monitors that tell you when it’s time to change the oil based on vehicle speed, engine temperature, climate conditions, number of cold starts and other factors. They can all cite examples from owners who say the oil-life monitors indicated they could go even longer than the recommended change intervals.

If you’re nervous about going 10,000 miles or more between oil changes, then do it every six months, when you probably should also have your tires rotated (also explained in your owner’s manual). GM says to change your oil at least once a year even if the service indicator warning light doesn’t come on. With longer recommended intervals between oil changes, it’s more important to check the oil level at least once a month to make sure you have enough.

But to change oil every 3,000 miles is probably wasting money. Environmentalists say it also adds to the glut of used oil that must be recycled or disposed, and the state of California is trying to discourage the practice.

If the guy at the quick-lube shop says he’s only trying to help you when he recommends frequent oil changes, consider this: It is not in the interest of an auto manufacturer for you to suffer premature engine failure caused by worn-out oil. If that happens, they might have to pay for repairs under warranty and probably will lose you as a customer. Yet, they’re the ones advising you to follow longer oil-change intervals.

 

Change the Transmission Fluid Tips

Yes, though how often this service should be performed varies by manufacturer and vehicle, and it’s open to debate.

The manufacturer’s maintenance schedule for many automatic transmissions doesn’t call for fresh fluid until 100,000 miles or, with some Ford transmissions, even 150,000 miles. A lot of mechanics say that is too long and it should be done at least every 50,000 miles. Manual transmissions may be on a different schedule, so it’s best to consult the maintenance schedule in the owner’s manual.

Like other vital automotive fluids, transmission fluid deteriorates over time. Hard use — such as frequent stop-and-go city driving, hauling heavy loads, trailer towing — will accelerate the deterioration. That kind of driving raises the operating temperature of the transmission, and heat puts more strain on the transmission and the fluid, which helps facilitate gear shifts, cools the transmission and lubricates moving parts.

If you do a lot of driving under high-stress conditions, you should check the transmission level more often and have a repair shop check the condition of the fluid. Transmission fluid often is red but can come in other colors, and as it deteriorates it tends to turn darker. It may also acquire a burned odor that could indicate it needs to be changed or that the transmission is developing mechanical problems. Another indication it needs changing is dirt or other debris in the fluid. When you take your vehicle in for an oil change or other routine service, the repair facility may urge you to pay for a transmission-fluid change or flush. Even if they can show you that the fluid is darker than original, that might not mean you need fresh fluid right now. Step back, check the maintenance schedule in your owner’s manual and see what the manufacturer recommends before you decide. This also will give you time to price shop.

Many repair shops use flush systems that force out the old fluid and pump in new fluid. Though that sounds good, some manufacturers say you shouldn’t do that (Honda is one; there are others), so you need to know this before you agree to a flush. Look in your owner’s manual. Some manufacturers, such as Honda, also call for their own type of transmission fluid and warn that using other types could cause damage. Moreover, some automatic transmissions have filters that should be cleaned or replaced when the fluid is changed. Make sure the repair facility is using the correct fluid and procedures for your vehicle.

If you have never changed the transmission fluid in your vehicle and have more than 100,000 miles on the odometer, should you change it now? We have seen mixed opinions on this, with some mechanics suggesting you should just leave well alone if you aren’t having shifting problems. Adding fuel to this theory are stories about older transmissions failing shortly after they finally received fresh fluid. We have a hard time accepting that fresh fluid causes transmission failure, so our inclination would be to have it done if you’re planning on keeping the vehicle a few years or longer. However, fresh fluid is not a cure for gears slipping, rough shifting or other mechanical problems, so don’t expect a fluid change to be a magic elixir.

Avoid Tire at a Time

You can safely replace only one tire if the others still have most of their tread.

Unlike the old days, when a pair of “snow tires” would be mounted to the drive wheels only for winter use, today we recognize that a vehicle should have four matching tires: same type, same model and, yes, even same degree of wear. The reason is simple: A car with four tires that behave the same — whether accelerating, braking or cornering — is balanced and predictable. If any of these factors are different at one or more wheels, traction characteristics can vary and performance will be unbalanced.

Tread depth is measured in 32nds of an inch, and most new tires typically have 10/32 to 12/32 (5/16 to 3/8) of an inch of tread. If a car’s other tires have lost only 2/32 or up to maybe 4/32 of their original tread depth, it’s probably OK to replace just the damaged tire.

There can be exceptions, though. Some manufacturers of all-wheel-drive vehicles recommend that all four tires be replaced, not just one or two, because a new tire will have a larger overall diameter than the other tires. The ones that have lost just a few 32nds of tread depth will spin faster than the new one, and the difference could cause an all-wheel-drive system to engage on dry pavement and possibly damage the system.

On an all-wheel-drive vehicle or one with a conventional four-wheel-drive system, all four tires would ideally be replaced at the same time so they all have the same amount of traction as well as the same diameter.

On a front- or rear-wheel-drive vehicle, similar guidelines apply. If half or more of the tread on all four tires is gone, replacing just one tire will result in one wheel spinning at a slower rate than the others, possibly sending false signals to the traction control and antilock braking systems. It also will result in one tire having more or less raction for acceleration, braking and cornering grip than the others, which can affect a vehicle’s behavior. On a two-wheel-drive vehicle, a better approach would be to replace both tires on the same axle. The best approach, though, is to replace all four if the tread on the old tires is significantly worn.

One way to avoid buying more than one tire is to have the tread on the new one “shaved” so it matches the depth of the others. Some tire dealers will shave off some tread depth on a special machine for a fee.

If you decide to replace only one tire, it should be the same model, size and tread pattern as the others. A different brand or model tire will have even greater differences in traction and number of revolutions per mile, and it’s likely to wear at a different rate. That means it could conceivably wear out faster than the others, even if it starts out with more tread depth.

Whether you decide to replace just one tire or more, tire experts advise that the new rubber should be mounted on the rear. If new tires are mounted on the front, the worn tires in the rear would be more susceptible to hydroplaning — riding on top of water on the road — and possibly causing the vehicle to spin in a turn.