304 North Cardinal St.
Dorchester Center, MA 02124
304 North Cardinal St.
Dorchester Center, MA 02124
Where is the routing information on a drive belt? Long drivebelt is on the first pulley groove closest to the engine. Short drivebelt is on the second pulley groove farthest from the engine.
Where do you find the routing information for an engine drive belt? To remove and install a new serpentine belt all that is required is knowing where the tensioner is located and a good breaker bar. Most vehicles nowadays usually have a belt routing sticker located somewhere in the engine compartment, making it even easier.
What do the numbers on a drive belt mean? The number following it is the outside length of the belt in tenths of inches. The inside length of the belt is typically 2″ less for a 4L belt, and 1-1/2″ less for a 3L belt. An example would be 4L460, which would be 46″ long outside, 44″ inside. The number following it is the inside length in inches.
Are serpentine belts directional? Although most serpentine belts are non-directional, it is possible to install some serpentine belts backwards. The grooved portions of the belt should be touching the grooved pulleys, and smooth areas of the belt should be touching the smooth pulleys.
Locate the belt tensioner on the front of the engine. The belt tensioner will have a spring-loaded arm on one end and a round pulley on the other end. The belt tensioner will also have a bolt head in the center of the pulley. This bolt head is used to relieve the tension from the belt.
EXAMPLE: 6PK1003 » 6 – This indicates the number of ribs on the belt; therefore, this is a 6-rib belt. » PK – The “P” indicates a metric designation, and the “K” indicates the belt is automotive per SAE J1459. » 1003 – This is the effective length of the belt expressed in millimeters.
4L Belt = The Outside Circumference (OC) – Minus 2 Inches. ( Example 4L320 = 30 Inch Inside Circumference) 5L Belt = The Outside Circumference (OC) – Minus 3 Inches. (
NOTE: A serpentine belt will usually go on only one way. In some instances it may be possible to install a serpentine belt the wrong way. If this happens, one or more pulleys will rotate in the WRONG direction, affecting the operation of the alternator, water pump, A/C compressor or power steering pump.
If you put the belt back on in the opposite direction, the ribs end up in different pulley grooves than the ones they’ve adapted to over time. This means that the belt has to re-adjust to a new abrasion pattern, which will lead to a dangerous loss of belt tension.
Appearance: Cycle the tensioner (mounted on the engine) through the entire range of motion (from stop to stop) by applying torque to the arm with a wrench. The tensioner arm should move smoothly and freely. Solution: If you notice a binding, sticking or grinding tensioner arm, the tensioner should be replaced.
The belt needs to be inspected for cracking. As the belt ages, the rubber becomes brittle which will cause it to crack. Once the belt begins to crack, it should be replaced as it can fail at any time.
If equipped with a tensioner screw, back off the tensioner screw. Then, push the alternator toward the other pulleys, loosening the belt. To loosen an NAI tensioner, loosen the locking nut or bolt, then back off the tensioner screw. Push the pulley toward the other pulleys or accessories, loosening the belt.
To be more precise, you can wrap a string tightly around the flat of the pulley where your belt rides. Mark the string where they overlap, then measure its length. Divide that number by 3.14.
V-Belts – Fractional Horsepower (FHP) Section 3L – Size 3/8″ (9.5mm) X 7/32″ (5.5mm)
BX v belts are a “cogged” style belt that can interchange on the same pulleys as “B series” or “5L series” belts. The BX belts can generate higher horsepower ratings due to the raw edge construction, which grips the pulley much better.
Using a 5.4” pitch diameter sheave, the 5L belt will transmit 2.39 horsepower. Using a B section belt on the same 5.4” pitch diameter sheave can transmit 7.21 horsepower, which is three times the horsepower of the 5L belt.
Serpentine belt replacement is easy because today’s automatic drive belt tensioners eliminate the need to loosen bolts or pry components into position for retensioning. Just rotate the tensioner, remove the old belt and install a new one.
Poor Driving Experience
So if you have searched for answers to the question, can a bad serpentine belt cause rough idle? The answer is yes.
If it causes excessive vibration, the belt should be replaced. If the back side (the side without the ribs) appears shiny or glazed, it is suffering from abrasion. Sometimes the abrasion is severe enough to expose cords beneath the rubber.
The idler pulley is a common part that’s found on the majority of the vehicles on the road. Its primary function is to provide tension and guide the engine drive belt. These belts wrap around the various parts of the engine such as the power steering pump, alternator, water pump etc
To help with installation timing belts are usually marked with marks that align with timing marks on the sprockets. If it’s fitted the wrong way round the marks won’t line up and either engine damage or madness will ensue. For instance a 151 tooth belt may have 48 teeth between crank pulley mark and exhaust cam mark.
Over time, the belt tensioner will lose its capacity to apply tension to the serpentine belt. When this happens, the belt can slip, which will cause damage or weaken it much faster. If your serpentine belt slips off multiple pulleys, it can cause extensive damage to your engine.
A seized tensioner cannot maintain proper belt tension. Dirt or mud can also jam the tensioner housing. A loose or worn pivot arm can allow unwanted movement; that results in belt noise and misalignment. Over time, this will increase belt wear and lead to premature belt failure.
Under no circumstances can you drive a vehicle without a serpentine belt because the serpentine belt serves the important function of delivering antifreeze to important parts of the engine. Without the serpentine belt, the power steering pump, which provides hydraulic pressure, no longer functions.
Belt misalignment and noise
A chirping noise that increases in frequency as the engine is revved up can be the result of belt vibration caused by misaligned pulleys. In fact most cases of belt noise are caused by misaligned pulleys and belts.