A clean engine compartment makes a used car look newer and better maintained. Some shops that perform engine cleaning services claim a clean engine even runs a little cooler because the gunk formed by dirt, oil and grease seals in some heat.
Appearances aside, does an engine that sparkles like new run any better than one that’s grimy from normal use? Probably not.
Though it is true that oily, greasy dirt that accumulates on an engine can trap some heat, it’s doubtful it would be enough to cause an engine to overheat or even run hotter than normal. If an engine overheats, the probable cause is more likely in the cooling system, or because the vehicle is towing or carrying too much weight or some other issue unrelated to the cleanliness of the engine bay.
However, there are benefits to cleaning a dirty engine. First, it can help determine where oil or grease is coming from, such as a leaky valve-cover gasket, so that a small problem can be isolated and repaired before it becomes a big one. In addition, because oil and grease can accelerate the wear of rubber hoses and plastic parts, cleaning off the gunk may save on repairs. And if you’re the type who likes to do some minor maintenance, such as checking the oil level or accessory belts, a clean engine means your hands and clothes are less likely to get dirty.
Many mechanics and detail shops recommend using a degreaser and tools such as a vacuum with a small nozzle, compressed air or a toothbrush to get at hard-to-reach spots. Those are preferable to blasting an engine with a high-pressure hose or steam cleaning an engine, because moisture can damage electrical parts.
The cosmetic appeal of a clean engine will probably be the biggest payback. Most used cars are thoroughly detailed before being put up for sale, including many sold by private owners, so buyers have come to expect to see a clean engine when they shop. A dirty engine on a used car will hurt its curb appeal.
The only guaranteed result of using premium gas in an engine designed for regular is that you will spend more money. As far as any tangible benefits, the chances are slim to none.
If your engine runs fine on regular, filling it with premium is unlikely to boost acceleration or fuel economy by more than insignificant amounts. No matter what you’ve heard, premium won’t do more to clean deposits from your fuel injectors or other parts of the fuel system because today’s regular gas contains the same detergent additives.
The main difference with premium is its higher-octane rating, 91 or higher compared with 87 for regular. The higher octane gives premium gas greater resistance to early fuel ignition, which can result in potential damage, sometimes accompanied by audible engine knocking or pinging. Higher octane allows engines to have higher compression ratios (for a more energetic explosion), more advanced ignition timing or forced-air induction like turbochargers or superchargers. They perform best when fed premium gas.
But if the vehicle manufacturer says your engine needs only 87-octane regular, that is what you should use. The higher octane of premium gas won’t make your car faster. The opposite is possible, because higher-octane gasoline technically has less energy than lower-octane; it’s the fuel’s ability to be compressed more without pre-igniting that results in more power when used in the appropriate engine. Premium gas is not “stronger.”
If you burn premium because you think it makes the engine peppier, that is probably psychological: I’m paying more, so I must be getting more. Some motorists claim they get better fuel economy with premium, but some of that could be due to favorable weather conditions (such as warm weather instead of cold) or other factors.
If you use premium because your engine knocks on regular, you are treating the symptom, not the cause. Something else might be causing the knock, such as carbon deposits or hot spots that should be diagnosed and treated by a mechanic.
Premium gas can cost 20 to 60 cents more per gallon, depending on where you live. Paying more to pump premium into a car designed for regular will have a low return on investment.
The drive belt is a reinforced rubber belt that allows the engine’s rotating crankshaft to drive components such as water pumps, alternators, air-conditioning compressors, power-steering pumps or superchargers. Your car may use separate belts for one or more components or hit multiple pulleys with a snaking serpentine belt. Belts are relatively inexpensive items that are best replaced when worn, damaged or simply old rather than after they fail. Serpentine belts in particular, because they power so many components, disable the car completely when they break.
How do I know if my drive belt is bad?
The accessory drive belt (also called a V, or serpentine, belt) drives the air-conditioning compressor, alternator and, on many vehicles, the power steering pump and water pump. If this belt breaks, none of those systems will work. If the belt is cracked, frayed or badly worn, it can slip on the pulleys it rides on, and the accessories it drives won’t receive all the power they need, which may trigger a warning light. A qualified mechanic can usually tell by looking if a belt needs to be replaced.
How often should I replace my drive belt?
It should be inspected at least every year on vehicles that are more than a few years old to check for wear, and it should be replaced as necessary. Most automakers call for periodic inspection of the belt, but few list a specific replacement interval. Though these belts often last several years, they can become cracked, frayed or worn on the side that is hidden from view.
Why do I have to replace my drive belt?
If this belt breaks, the battery won’t get recharged, the air conditioner won’t blow cold air and the power steering will go out. In addition, if the belt drives the water pump, the engine could overheat.
How much should I pay?
The cost of repairs can depend on where you are as much as it does on what you need fixed. To get an estimate for your repair, go to our estimator, plug in your car’s year, make and model information, add your ZIP code, and choose the repair you need. We’ll give you a range for what your repairs should cost in your area.
Most owners probably don’t know that their vehicle has a crankshaft position sensor until the engine dies, won’t start or starts running poorly. Then they find out they need a new one.
The crankshaft position sensor, typically mounted near or on the crankshaft, tells the engine computer how fast the engine is running. That’s so the control unit knows when the spark plugs should ignite the air-fuel mixture and, in some engines, when to inject fuel. These sensors are used on virtually all engines that have distributorless ignition systems.
If the sensor fails, the computer won’t know how to set the ignition timing, so the engine may stop running or refuse to start. It could also stall or run badly, possibly triggering the check engine light. Excessive heat is a frequent reason these sensors fail, and they also can stop working because of faulty electrical connections or wiring.
Some vehicles also have a camshaft position sensor that allows the engine computer to monitor the position of the camshafts (or camshaft), which open and close the valves, for more precise fuel and ignition management.
These sensors are not listed as routine maintenance items, but they often fail without warning. For that reason, some repair shops recommend they be replaced on high-mileage engines as preventive medicine.
Because a bad sensor doesn’t always trigger the check engine light — and some of the same symptoms could be caused by other problems in the fuel or ignition systems — sensors should be tested with a diagnostic scanner or multimeter before deciding to replace them.
It could, depending on the age, condition and brand of vehicle you’re driving. The maintenance schedules for some recent Hyundai engines, for example, call for a valve clearance inspection at 60,000 miles. Some Hondas call for an inspection at 110,000 miles. Some manufacturers advise valves should be inspected only if there is excessive valve noise. Others don’t mention valve clearance in their maintenance schedules.
Valves are opened by camshaft lobes on overhead camshaft engines and by rocker arms on pushrod engines. With extended time and use, the original clearances between these parts and the valve stems become bigger (with exhaust valves, the clearance can become tighter over time). That often leads to a clattering noise or more engine vibration that a driver might not notice for quite a while, because it increases gradually.
Intake valves open and close to let the air-fuel mixture (or just air in some modern engines) enter the combustion chambers, and the exhaust valves allow exhaust gases to escape. Too much or too little valve clearance can result in poor performance or a rough idle because the engine can’t “breathe” normally and operate at peak efficiency. Too much clearance means the valves will likely clatter and, over the long term, cause damage to the valves and/or camshaft lobes or rocker arms. If there’s too little clearance the valves won’t fully close, causing excessive heat, and the engine will lose power.
If your engine generates a loud clatter, it could be time for a valve clearance adjustment — though on some engines the valves don’t generate noise when there’s too much clearance. Loss of power could be a sign of a weak or broken valve spring, and a tapping noise could be caused by a loose rocker arm, so a clearance adjustment may not be all that’s needed. The mechanic won’t know for sure without inspecting the valves.
Because adjusting valve clearance (or “lash”) requires removing the valve cover (or covers on V-type engines) and checking both intake and exhaust valves, it isn’t a quick in-and-out maintenance item like an oil change, especially on engines that have three or four valves per cylinder. Plan on at least a few hours at the shop and a charge just for the inspection.
Eliminating valve clatter is one benefit of adjusting the clearance, but the engine will also likely become smoother and more responsive. In addition, correct clearance can extend the life of the valve system.
Maybe forever, if you rely on an overly liberal interpretation of the maintenance schedules set by some vehicle manufacturers. That doesn’t mean you should ignore them or even accept the manufacturer’s recommendations, though; instead, add them to your list of items that should be checked annually after the first three or so years of ownership.
With accessory drive belts, most manufacturers recommend only a periodic inspection for cracks, fraying or other visible wear, and on some GM vehicles the first inspection isn’t until 10 years or 150,000 miles, when someone else might own the vehicle.
Hoses? What about them? Most owner’s manuals don’t even mention radiator or coolant hoses (except that they can get really hot on an overheated engine). Other hoses, such as for the power steering or air conditioner, usually are mentioned only as something that should be checked as part of routine maintenance or when leaks are suspected.
Coolant hoses typically last several years, though anything longer than 10 years may be pushing the limits. Rubber weakens with age and from repeated exposure to hot coolant, so the older they get the higher chance they’ll leak and cause the engine to overheat.
Drive belts are usually the serpentine type that snake their way around pulleys to power the alternator, air conditioning compressor, power steering pump and perhaps the water pump, and they’re designed to last several years.
When to replace a drive belt is a judgment call by a repair technician, and it’s up to the vehicle owner to decide if the time is right given the manufacturers have largely chosen to stay out of it. We would err on the side of caution, because when a drive belt breaks your car comes to a halt. Depending on where this happens and when, a belt that fits your car may not be available until tomorrow, leaving you stranded.
Don’t confuse a drive belt with a timing belt, which connects the crankshaft to the camshafts and controls the timing of when valves open and close. Timing belts are out of view behind a timing cover and more complicated and expensive to replace, mainly because of the additional labor. Many vehicles have timing chains that are considered good for the life of the vehicle, but timing belts usually have a recommended mileage before changing. In some cases, that’s as soon as 60,000 miles but in others it can be 100,000 or more.
You should be very concerned, because an overheated engine can be far more than an inconvenience. In extreme cases, driving an overheated engine even a short distance can destroy the cylinder head, engine block or internal parts.
Fortunately, most modern vehicles have a gauge that displays a constant temperature reading of the coolant circulating inside the engine, giving the driver an early warning about the cooling system.
The normal operating temperature for most engines is in a range of 195 to 220 degrees Fahrenheit, though most dashboard temperature gauges don’t show an exact temperature. Instead, there are typically markings for cold and hot on the edges of the gauge and a normal range in the middle. In most vehicles, the temperature needle will be at or near the center when the engine is at normal operating temperature, which usually takes at least a minute or two to reach after starting a cold engine.
In some vehicles, the needle may never reach the middle of the gauge, so don’t be alarmed if it stops short of the midpoint. Instead, you should monitor where it is when the engine is fully warm so that you know what “normal” is for your engine. That way, if the needle starts creeping up higher, closer to the hot mark, you’ll have early notice that something is wrong in the cooling system.
Using the air conditioning at full blast, stop-and-go driving on a scorching day, and towing can raise the engine temperature above normal, so don’t panic if there’s a small change in the gauge reading. You can pull off the road for a while or turn off the A/C and turn on the heater to try to cool things off.
If the temperature gauge consistently shows the engine is warmer than normal, have your cooling system checked ASAP.
Today, an increasing number of new vehicles don’t have temperature gauges. Instead, they have a warning light that (usually) glows blue when the engine is cold — one way of telling you that turning on the heater will generate cold or cool air. The blue light goes off once the engine reaches its normal temperature.
All vehicles also have a warning light that’s supposed to come on when the engine exceeds its normal temperature (it also illuminates for a couple of seconds when you start the engine). Without a gauge, though, it’s anybody’s guess as to how high above normal the temperature is or how long it’s been above normal.
If a red or yellow temperature warning light comes on, assume the worst: get off the road, shut off the engine and call for help. It’s better to play it safe than risk having to buy a new engine. Or a new car.
If your engine misfires, hesitates, stalls, gets poor mileage, is hard to start or has failed an emissions test, it clearly needs something, though a tune-up in the traditional sense might not be the cure.
If you tell a repair shop you need a tune-up, the mechanic should ask why you feel you need one before recommending any service. Just like a doctor should ask what symptoms you’re experiencing, a mechanic should seek to diagnose the problem. And just as a doctor may recommend some tests, a mechanic may do the same.
You can speed the process by being ready to describe what happens and when (such as whether your car hesitates when the engine is cold or when passing at highway speeds), any sounds you hear and what you feel when your car’s “illness” shows up.
One caution about lower fuel economy: You should expect it to go down at least a little during the cold months, and maybe a lot. Colder temperatures make your engine and charging system work harder. In addition, winter gasoline blends have slightly less energy content than summer blends, so they don’t deliver as many miles per gallon. A tune-up won’t make Old Man Winter, or his effects, go away.
What are symptoms that might make you think you need a tune-up?
* A misfiring engine (when spark plugs ignite at the wrong time) could be caused by worn or fouled spark plugs. Bad spark plugs can also cause low fuel economy, hard starting and sluggish acceleration. Most plugs, though, should last 100,000 miles or more, and engine computers do a remarkable job of compensating for worn plugs, so that might not be the main or only culprit.
* A dirty or clogged engine air filter is more likely to reduce acceleration than fuel economy, according to tests conducted by the EPA. Because filters get dirty gradually over time, you might not notice a small but steady loss of performance until your car is accelerating like a turtle. But if you haven’t changed the filter in a couple of years (or sooner in areas that have a lot of soot in the air), that could be part of the problem.
* Engine deposits caused by low-quality or contaminated gasoline create drivability problems, and the cure for that might be a fuel system cleaning, either by a repair shop or with a gas-tank additive.
* An illuminated check engine light signals when something is amiss in the emissions control system, but depending on what the issue is it could also affect fuel economy or engine performance, so don’t ignore it. A faulty oxygen sensor, for example, leaves the engine computer in the dark about how to set the air-fuel mixture, and that can result in poor fuel economy.
* An old oxygen sensor (say, 90,000 miles or more) may still work well enough that it doesn’t trigger the check engine light but could still hurt fuel economy. Engine performance can also be reduced by more serious internal problems, such as valves that don’t seat properly or worn piston rings, or by restrictions in the exhaust system.
Because the same symptoms can suggest different problems, and there are often several possible causes and cures, it’s better to consult a professional mechanic than to try to be one if you have neither the experience nor the right equipment to diagnose drivability problems.In short, rather than ask for a tune-up, tell a mechanic what you’re experiencing and ask him or her to find the cause.
The labor time it takes to replace the motor mounts can bring the price to more than $1,000 on some vehicles. On the Honda Odyssey minivan, for example, we’ve seen price quotes of $1,000 for just one new motor mount and $1,800 for all three.
Many motor (or engine) and transmission mounts can be replaced for far less, and some do-it-yourselfers brag that they’ve replaced theirs for less than $100. Be aware, though, that lifting any engine is serious business, and if you don’t know what you’re doing, you could severely damage your engine and your car.
Engine mounts are blocks of rubber mounted on steel brackets that are bolted into place to support the engine and reduce the amount of engine vibration and noise felt and heard in the passenger compartment. Usually there are three or four. If the rubber wears out or cracks, or if the steel brackets break, common symptoms are more engine vibration or movement under throttle and more noise. The engine might even move a few inches or more when mounts are broken.
Replacement mounts may not be that expensive; they can run from as little as $50 to as much as $200 at parts stores, depending on the vehicle, though liquid-filled mounts are more expensive.
But if you’re paying a shop to replace the mounts, the cash register doesn’t stop ringing once the parts are purchased. It can keep ringing for three or four hours if the engine is difficult to lift out of the way and other parts have to be removed or loosened to allow that. In cases where cooling and exhaust parts are involved, you may need new gaskets or hoses.
The engine typically has to be jacked up or lifted with an engine hoist to take all the weight off of broken mounts before they can be replaced. Manufacturers often leave little working room, extending the time it takes to replace the mounts and put everything back together.
Most repair shops will use a standard labor time estimate for replacing motor mounts on a particular vehicle, but some shops may quote less time than others, so it pays to shop around and ask. In addition, the hourly labor rate will vary among shops, so ask about that, too.
For some vehicles, you’re advised to change the coolant every 30,000 miles. For others, changing the coolant isn’t even on the maintenance schedule.
For example, Hyundai says the coolant (what many refer to as “antifreeze”) in most of its models should be replaced after the first 60,000 miles, then every 30,000 miles after that. The interval is every 30,000 miles on some Mercedes-Benz models, but on others it’s 120,000 miles or 12 years. On still other Mercedes, it’s 150,000 miles or 15 years.
Some manufacturers recommend changing the coolant more often on vehicles subjected to “severe service,” such as frequent towing. The schedule for many Chevrolets, though, is to change it at 150,000 miles regardless of how the vehicle is driven.
Many service shops, though — including some at dealerships that sell cars with “lifetime” coolant — say you should do it more often than the maintenance schedule recommends, such as every 30,000 or 50,000 miles.
Here’s why: Most vehicles use long-life engine coolant (usually a 50/50 mixture of antifreeze and water) that for several years will provide protection against boiling in hot weather and freezing in cold weather, with little or no maintenance[EM1]. Modern vehicles also have longer intervals between fluid changes of all types partly because environmental regulators have pressured automakers to reduce the amount of waste fluids that have to be disposed of or recycled.
Coolant can deteriorate over time and should be tested to see if it’s still good, as it can be hard to tell just by appearances. Even if testing shows the cooling and antifreeze protection are still adequate, antifreeze can become more acidic over time and lose its rust-inhibiting properties, causing corrosion.
Corrosion can damage the radiator, water pump, thermostat and other parts of the cooling system, so the coolant in a vehicle with more than about 50,000 miles should be tested periodically. That’s to look for signs of rust and to make sure it has sufficient cooling and boiling protection, even if the cooling system seems to be working properly. It can be checked with test strips that measure acidity, and with a hydrometer that measures freezing and boiling protection.
If the corrosion inhibitors have deteriorated, the coolant should be changed. The cooling system might also need to be flushed to remove contaminants no matter what the maintenance schedule calls for or how many miles are on the odometer. On the other hand, if testing shows the coolant is still doing its job and not allowing corrosion, changing it more often than what the manufacturer recommends could be a waste of money.
If steam is pouring from under your hood, a temperature warning light is glowing bright red on your dashboard or the needle in the temperature gauge is cozying up to the High mark, it’s time to pull off the road and shut down the engine before it fries from overheating.
Any indication of overheating is a serious matter, so the best course of action is to shut down the engine to prevent further damage. Driving a car with an overheated engine can warp cylinder heads and damage internal engine parts such as valves, camshafts and pistons.
Even letting the engine cool for an hour and topping off the radiator with a 50-50 mix of antifreeze and water may not fix what’s wrong. Here are some reasons an engine will overheat:
- The coolant level could be extremely low, because of long-term neglect or because a leak has developed in the radiator or radiator hoses. Coolant circulates inside the engine block to cool it, and the leak might be in the block, or from the water pump or heater hoses. Old coolant loses its corrosion-inhibiting properties, allowing rust to form and ultimately causing damage.
- The thermostat that allows coolant to circulate may be stuck in the closed position or a clog may have developed, perhaps from debris in the cooling system.
- The engine cooling fan has stopped working or the radiator’s cooling fins are clogged with debris so that the air flow that reduces the coolant temperature is restricted.
- The radiator cap has gone bad and no longer maintains enough pressure in the cooling system, allowing coolant to boil over (engines normally operate at about 210 to 220 degrees Fahrenheit).
- The head gasket that seals the gap between the cylinder head and engine block may have failed, allowing coolant to leak inside the combustion chambers. The steam should be visible coming out of the exhaust system.
- The water pump has stopped working or the belt that drives it broke or is slipping and not pumping enough coolant.
- You’ve been towing a 5,000-pound trailer with a vehicle equipped to tow only 2,000 pounds, exceeding the vehicle’s cooling capacity. (You probably also strained the transmission.)
Checking your engine coolant level in the overflow tank on a regular basis can help avoid disasters. If you have to keep topping off the coolant, that’s an indication of a small leak that should be taken care of before it becomes a major one. Having your coolant tested and the entire system inspected by a mechanic every couple of years is an even better way to prevent cooling system disasters.
Yes, it does matter, because some brands contain more detergent additives that can prevent carbon deposits from forming inside your engine.
These are the so-called Top Tier brands that use considerably more detergent additives than is required by the EPA. Several vehicle manufacturers recommend using Top Tier gas so they and their dealers don’t receive complaints from owners about poor performance or fuel economy caused by carbon deposits, fouled fuel injectors or other issues.
Most major oil companies have adopted the voluntary Top Tier standards for detergent additives, including Shell, ExxonMobil, BP, Chevron, Phillips 66, Texaco and Valero, among others.
The vehicle manufacturers claim that using other brands of gas over time can allow carbon deposits to form in combustion chambers, which can cause engine knock or pinging (premature fuel ignition), and on intake valves, which can impede valve operation.
This doesn’t mean you should never use anything except Top Tier gas.
As a practical matter, the smaller, independent gasoline brands are often cheaper than the major brands, and for people on a tight budget, saving pennies per gallon matters. Additionally, for some motorists, the nearest Top Tier station may be miles away, making it impractical to fill up there consistently. And if you’re on an interstate highway and your tank is nearly empty, you have to take what you can get.
Some vehicle manufacturers, such as Hyundai and Kia, suggest that owners who don’t use Top Tier gas add a fuel-system cleaner to their tank periodically to clean out any deposits or gunk. You should first check your owner’s manual to see what the manufacturer says about Top Tier gas and fuel additives.
Using Top Tier gas as often as is practical and economically feasible, plus periodically adding a fuel system cleaner if you often use other brands of gas, should do the trick.