Serpentine belt popped off engine while running

Serpentine belt popped off….belt appears to be in good shape…..noticed wobble in harmonic balancer recently…..any advice would be appreciated

My car has 120000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hello there, many faults will cause the drive belt on your 2007 Dodge Durango to fall off. In many cases the belt comes off from either a seized pulley, or a pulley that is walking. If your harmonic balancer pulley appears loose and walking it may be the cause of the belt coming off. There are are few other potential cause such as the alternator, belt idler, failing belt, idler pulley, power steering pump, or the water pump. A qualified Technician such as one from YourMechanic will be able to diagnose your belt issues and make any repairs required to resolve the issue.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

Drive Belt, Serpentine Belt, and V-Belt are basically different names for the same thing. The Drive Belt / Serpentine Belt is a rubber belt mounted on the exterior of your car engine. The belt is driven by your engine and is used to power or drive the accessory devices that are needed to make your car functional.
Serpentine belts are much longer and wider than older V belts. Improved material quality lets belts last much longer. A narrow, deep V-belt design evolved into a wide, flat belt with teeth. Several V belts on older engines have been combined into one serpentine belt on newer engines.
If the harmonic balancer/crankshaft pulley is out of position that can contribute to belt breakage because the pulleys will not be in the same plane.
A serpentine belt (or drive belt) is a single, continuous belt used to drive multiple peripheral devices in an automotive engine, such as an alternator, power steering pump, water pump, air conditioning compressor, air pump, etc.
A v-belt is flexible and transmits power from one shaft to another. As seen in Figure 2, a v-belt has a trapezoidal cross-section. The wedge-shaped belt fits perfectly into the wedged groove of a pulley. Due to this good fit, v-belts transmit more force than flat belts.
There are three common V belt types: Classical V-belt (classified by their dimensions from A to E), Narrow V series (ranked by their sizes 3V, 5V, and 8V), and light-duty Fractional Horsepower belt (classified by their dimensions 2L, 3L, 4L, 5L). The letter X classifies their counterpart cogged belt.
The V-ribbed belt is flatter and wider than the V-belt. Its longitudinal ribs enable it to transmit higher forces. Smaller angles of contact are also possible with the V-ribbed belt. Since the late 1980s/early 1990s, V-ribbed belts have almost completely replaced V-belts in the field of passenger cars.
Ray: Plus, it does have a role in “balancing” the crankshaft. And without it, you can do damage to the crankshaft and the engine bearings. So you really do have to replace it.
Without the harmonic balancer there is a high risk your crankshaft would crack or a serpentine belt would be thrown off track. A simple way to think of the harmonic balancer is like a massive stress reliever.
A V-belt is a wedge-shaped belt manufactured out a rubber compound, reinforced with a tensile cord specifically engineered to transmit power into movement. V-belts can be found in driving mechanisms, such as engines in air compressors, fans, and pumps.
A V-belt is a rubber belt used for driving mechanisms in an engine such as the fans or water pump. A V-belt must be the right size, extending slightly out of the pulley groove. The V-belt has driven mechanical parts of car engines since the 1920s.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

hey i had a belt break while traveling on my 2004 honda pilot. It is the small belt and not the serpentine belt. The mechanic t
ANSWER : Hello. The smaller belt is known as your timing belt, and it works inside the engine to keep mechanical components aligned with each other during the compression cycle. The serpentine belt, which is the big belt, drives the alternator, water pump, AC compressor, and a couple of other components. If the small belt broke it is likely the timing belt. This will cause the car to stall, lights to illuminate, and can even cause serious damage to the engine. Typically replacing a timing belt is a lot more complicated and expensive than replacing a serpentine belt. You may want to receive a second opinion on the car before you go ahead with repairs.

My engine belt is coming off slowly now it is halfway out. Does this mean i need to replace the belt or it is a faulty engine?
ANSWER : When the drive belt is walking itself off the drive pulleys, it can be due to tension or pulley damage. If the belt tensioner spring is weak or broken, the belt will be loose and can begin to come off the pulleys. Also, if any of the pulleys, whether crankshaft, water pump, etc, are damaged and not spinning properly, this can put a side load on the belt and begin pushing it off any or all pulleys. Have a technician inspect the vehicle as soon as possible to avoid over heating the engine.

I have a 96 Ford ranger with cel p0340 I have recently done a timing belt, engine runs great replaced cmp sensor cel still on
ANSWER : Hi There,
This may happen for a couple of reasons. First, check to be sure that the connections to the sensor are clean and not faulty or broken. Secondly, check to be sure you replaced the correct sensor as there are two camshaft position sensors in some applications. If you need further help with this, please reach out to us here at YourMechanic as we are always here to help.

Serpentine belt is rubbing on the engine cover at the belt tensioner pulley 2004 Hyundai Tiburon
ANSWER : Hi there – I would start by doing a visual inspection of the serpentine belt, and the pulleys – are they visually in line? If not, which pulley is out of line in the direction of the engine cover? Are there bushings on the alternator mount which have softened, and are allowing the alternator to "give" such that the serpentine belt is close to the cover? The crankshaft pulley is not likely moving at all. Is the cover where the rubbing occurs coming loose, and moving into the serpentine belt? For assistance, I would recommend a serpentine belt replacement by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

The engine of the car runs, but when I push the gas pedal it does not accelerate, and the engine does not rev.
ANSWER : Hello. It sounds like you may have an issue with your throttle position sensor. This sensor sends a reference voltage to your power-train control module, which uses that to determine ignition timing and fuel trims. If the power-train control module is not detecting the proper signal from the throttle position sensor, the engine may not accelerate properly. It’s probably a good idea for you to have a professional mobile mechanic come to your location and complete a car is slow to accelerate inspection first, so they can pinpoint what is causing this issue to occur and they will recommend the right repairs be completed.

belt is missing, squeeling sound before stopped engine, once stopped saw smoke coming from engine department
ANSWER : Hi there:

In cases like then when you’re not sure what component needs to be replaced, it’s always best to have one of our professional mobile mechanics complete a car is hard to start inspection first. This will allow the mechanic to review your car for damage that is causing the symptoms you’re experiencing and then recommend the right replacement or repairs be completed to resolve your issue.

1991 Toyota Land Cruiser eating through serpentine belts, why?
ANSWER : Hello there, a few different faults will cause your 1991 Toyota Land Cruiser wear belts quickly. When belts wear this fast it is not an issue with the belt, there is an underlying problem. The most common is a failed belt adjuster / tensioner, an out of line pulley, dragging accessory. A qualified Technician such as one from YourMechanic will be able to diagnose your drivebelt wear and make any repairs required.

Honda Pilot engine misfire when cold out and engine running warmer than usual?
ANSWER : Hi There,
It sounds like you may have a faulty coolant temperature sensor. This sensor relays the temperature of the coolant back to the ECM which uses this information to control many things such as when to turn the coolant fans on and off as well as how much to adjust the air to fuel ratio in the motor. Both of these functions are affected when this sensor is not working properly. If the senor is reading incorrectly, this may cause inaccurate temperatures to be read, thus causing inaccurate adjustments to be made to fuel and to the operation of the cooling fans (i.e. staying on too long or not coming on soon enough to help keep the motor cool). I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.