After belt replacement, belt tensioner squeaks and is loose

ANSWER : More likely mileage and time wore the tensioner out. The tensioner bearing wears out with mileage – it’s good to replace the tensioner pulley/bearing when replacing the belt. The tensioner itself is spring-actuated, and the spring can get weak over the years. The squeaking is likely from the tensioner bearing itself. If you decide to get it fixed, consider YourMechanic, as a certified technician can help you replace your belt tensioner as necessary.

ANSWER : Hey there. You will need to remove the entire housing that contains the spring. Belt tensioners are replaced as a unit. In the case of the 4.7L Toyota Motor, you will need to remove a couple of the plastic timing covers to allow the tensioner assembly to slide out and off of its studs. Once you remove the timing covers, you will be able to see the entire assembly and identify which bolts and nuts must be removed to remove the tensioner. You may need to remove the fan belt pulley to remove one or more of the covers. I suggest purchasing a new one first, then you will be able to see all that needs to happen. If you should need help with this project, or would simply like it to be done for you, have a certified technician from YourMechanic come to your car’s location to assist with your drive belt replacement.

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.

ANSWER : Hello. If the belt driving the A/C compressor only drives the A/C compressor and nothing else, you can remove it with no consequences. The fan shroud is not optional equipment however as it has both a cooling system function and a safety function.

Depending on your climate, you might consider diagnosing the A/C system and repairing it. If you use a service such as YourMechanic, it will often be economical enough to do it, particularly if the fault is limited.

Even if the compressor shaft sealing is leaking (would be likely after 25 years), that is fixable in the field. Feel free to contact YourMechanic if you have additional needs relative to this or the replacement of your power steering, alternator, A/C belts.

ANSWER : Check to be sure that the new belt is actually the right part number or, better yet, use an OEM (dealer) belt. Also, be sure the tensioner is the right part number or use an OEM sourced tensioner. Check to be sure that all of the pulleys and accessories (e.g., alternator, water pump, A/C compressor) that are driven by the serpentine belt are all operating in the same plane. It is not unusual for the pulley on the crankshaft harmonic balancer pulley to move (generally outward) relative to its original position. The pulley is rubber bonded and over time can move. If that pulley moves, that means that the belt groves are no longer running in a perfect plane and that alone can cause slipping. If you request serpentine belt inspection a certified Mechanic, dispatched by YourMechanic right to your location, will identify the problem and thence get the issue resolved for you promptly. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : At the next cold start, try this: Take a spray bottle with some water and spray the belt then start it. If you hear the noise, then the problem may not be with the belt or tensioner. If you do hear it, then it’s possible that one of the pulleys (a/c,water pump,etc) may be slightly glazed or out of round. It’s also possible that a bearing, such as in the water pump, alternator, or a/c compressor clutch may be the issue. Sometimes a bearing that is on it’s way to failure can squeal when cold until it warms up. Alternator bearings are a common source. A mechanics stethoscope may be a good tool to locate a squealing sound. Since the noise is primarily on a cold start, the vehicle may need to sit for several hours or even overnight to get the noise to occur and found with the stethoscope.

ANSWER : Hey Dan, thanks for inquiring. I don’t know that you necessarily need to replace your pulleys, neither tensioner or idler. However, if you are hearing a squeaking from your engine and suspect the pulleys are the problem then replace them as needed. I don’t think you really need to replace pulleys every time you replace the belts.

ANSWER : Hi there. The old wives tale of putting water on a serpentine belt actually is true. The water creates a temporary shift in weight distribution and can reduce the squealing noise. My suspicion is that your belt is probably fine, but the pulley’s are damaged and need to be replaced. Typically a professional mechanic will recommend replacing the pulley’s the same time you complete the belt replacement. This significantly reduces the possibility of alignment issues. I would recommend not taking your car to a mechanic, but have the mechanic come to you. Have one of our professional mobile mechanics complete a car is making a noise inspection first. This will allow them to identify the source of the noise and recommend a repair.