Timing belt is tight and yet appears to be slipping several teeth when belt is rotated,
I have a 2005 Subaru Outback 2.5 SOHC. I changed the timing belt, water pump, all the pulleys and had a valve job done. I have done several timing belt changes on different subaru's, and have never had this issue. After the belt is on, both belt and sprocket marks are lined up, i do a full belt revolution and the marks on the belt are no longer lined up with the sprocket marks. Turn the sprockets back to the normal timing marks and they are still lined up, but belt marks are not…….whats going on…John
My car has 180000 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
This is okay since there are more notches on the belt than the amount on the sprockets. Once you aligned the first time the belt marks will almost never line up perfectly again. The marks are used to put the belt on correctly. They aren’t used as an indicator after the engine is turned again. You should be okay to start the motor as long as timing marks on pulleys line up. If you run into any issues, have a certified technician, like one from YourMechanic, assist you with the replacement of the timing belt.
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The tensioner that keeps the belt taut is pressurized by the engine oil. If the tensioner has no oil pressure, the belt will become loose and possibly disengage from the pulleys and/or break. If the camshafts don`t have enough oil pressure to operate properly, they will also lock up, causing the timing belt to break.
What Happens When The Timing Belt Is Too Loose. If the timing belt is too loose, your engine may not run as smoothly as it should. A loose timing belt allows the crankshaft and camshaft to be less than perfectly in sync with each other. The engine will still run, but not as smoothly.
A squealing noise could be from a lack of tension between the belt and pulleys. Worn belt ribs and a misaligned belt can result from an improper installation that can cause an annoying chirping sound. Timing belts are known to occasionally have a ticking sound as well that can stem from low engine oil or other issues.
Backlash occurs due to clearance between the timing hole in the belt and the pulley`s timing pin. Some clearance is generally needed to avoid interference and let the pins fit into holes, but it can cause backlash when the belt is reversed.
Engine Misfiring
The timing belt is responsible for synchronizing the valves and cylinders in your engine. If it slips too far or falls off the pulley system, it may cause one of the cylinders to open or close too early. This will cause a misfire, and a noticeable loss of acceleration.
To work effectively, a timing belt must have a certain amount of tension controlled by the timing belt tensioner. In older cars, these tensioners would need adjustment if the timing belt became loose, but modern vehicles are equipped with an automatic timing belt tensioner that does not require adjustment.
Belt “Squealing” or “Whining” Noises
A common warning sign of an issue with your timing belt pulley is a high pitched squealing sound coming from the belt. Think of this sound as an alarm bell signaling a need for repair or replacement.
I`m afraid your 2.5 litre Subaru flat four is an interference engine. If the cam belt breaks, expect a big bill! Two things seem to kill these engines. Bottom end wear due to excessive oil change intervals (or a refusal to check the oil level!), and cam belts breaking.
Timing belts
We will start with the belt part number 13028AA240 which is made by Unitta for Subaru.
An over-tightened belt can burn out any bearing that the belt rotates on, including alternator, power steering pump, A/C compressor, idler pulleys, etc. An over-tightened timing belt can ruin any pulley bearing it is connected with.
Timing belt installation should be a snug fit, neither too tight nor too loose. The positive grip of the belt eliminates the need for high initial tension. Consequently, a belt, when installed with a snug fit (that is, not too taut) assures longer life, less bearing wear and quieter operation.
Backlash: Backlash in a synchronous belt drive results from clearance between the belt teeth and the pulley grooves. This clearance is needed to allow the belt teeth to enter and exit the grooves smoothly with a minimum of interference. The amount of clearance necessary depends upon the belt tooth profile.
Trouble accelerating can come from a few different engine issues. These include, but are not limited to, dirty fuel injectors, low fuel pressure, and restricted airflow. A problem with the mass airflow sensor, throttle position sensor, or engine speed sensor can also cause a car to have difficulty picking up speed.
This hesitation while accelerating can be the result of a number of issues, including something like a clogged fuel filter or even a broken fuel pump. Sometimes, something could also be wrong with the transmission.
Common causes of why a car feels sluggish when accelerating include dirty mass air flow sensor (MAF), faulty spark plugs, defective throttle position sensor, clogged catalytic converter, faulty oxygen sensor, clogged air filter, and fuel system malfunctioning.
A worn timing belt will affect your engine`s starting speed as it is attached to the pulleys that drive the crankshaft. Eventually, the belt can slip on the camshaft drive causing the engine cylinder to open and close at the wrong time.
Cambelts or timing belts usually need to be replaced, usually between 40,000 and 100,000 miles. Alternatively, for lower mileage cars, the belt is advised to be replaced around four or five years.
Can you drive with a broken timing belt? Your car cannot run with a broken timing belt . By the time the belt snaps, the damage is already done, and you will not be able to drive at all. You will need to have the vehicle towed to an auto repair workshop.
Continuing to drive with a broken serpentine belt also puts your car`s engine at risk and can lead to extremely expensive repair costs, so play it safe and don`t drive any further than you need to.
A squealing or noisy belt is one of the most common symptoms of a slipping or worn serpentine belt. Squealing can be more pronounced when you`re climbing a hill and running your heater or air conditioning at the same time. Squealing can also occur after you drive over deep puddles or have an undercarriage car wash.
Continuing to drive with a broken serpentine belt also puts your car`s engine at risk and can lead to extremely expensive repair costs, so play it safe and don`t drive any further than you need to.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Timing belt is tight and yet appears to be slipping several teeth when belt is rotated,
ANSWER : This is okay since there are more notches on the belt than the amount on the sprockets. Once you aligned the first time the belt marks will almost never line up perfectly again. The marks are used to put the belt on correctly. They aren’t used as an indicator after the engine is turned again. You should be okay to start the motor as long as timing marks on pulleys line up. If you run into any issues, have a certified technician, like one from YourMechanic, assist you with the replacement of the timing belt.
When I went to change the timing belt there were 25 teeth were missing but it didn’t jump time – how is this possible?
ANSWER : Not all the teeth need to be present in order for the pulleys to turn. However, the only way to tell if the cam and crankshaft were really in the right position relative to one another is to line them up before taking the belt off and when the engine is at TDC on cylinder 1. If all the pulleys were lined up to the marks that are embossed on the engine, the only explanation is that the few remaining teeth were stout enough to turn the pulleys without breaking. However, even that doesn’t seem likely, especially since 25 missing teeth in a row would suggest that there weren’t even enough teeth for the belt to fully engage the crankshaft timing gear, thus slippage would have been inevitable. If the 2.0L engine you have has a double overhead cam, that is an interference engine (the single cam version of the 2.0L is a non-interference engine). If you’d like a professional technician check out the engine for damage, due to the failed belt, and/or install the new timing belt, consider YourMechanic.
timing belt and driving belt replacement interval
ANSWER : The timing belt should be checked every 24 months or 30K miles and replaced every 48 months or 60k miles. You are not due until 173k for a timing belt replacement, but should get inspected at 143k. The accessory belts should be inspected at every oil change and replaced as needed.
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.
hi- i got an estimate to replace my timing belt and water pump for my 2012 pilot. Do these figures seem right? Timing belt (35.00)
ANSWER : Hi there. That is a fairly good and detailed estimate for this type of service. It also falls within the price estimation to have a mechanic shop complete this service. However, you might want to consider a third option, of having a professional mobile mechanic come to your location and complete the timing belt replacement and water pump replacement. Simply click the blue links to receive an estimate for both services.
1992 Acura Legend, when the timing belt goes, is it common for the valves to bend?
ANSWER : If the timing belt break off, the engine’s pistons will hit the valves as the pistons are moving. The engine is an interference engine and can cause damage to the internals of the engine. The last time the belt came off, the engine may have been running at an idle or not under power. It is possible for the valves to be bent. What I recommend doing is performing a leak down test on the engine with a timing belt on the engine and properly timed to determine if the valves were in fact bent. If all of the cylinders have a 80 percent hold and not leaking, then the engine is fine. If there is a mass leak on a cylinder, then the piston did some internal damage. I recommend seeking out a professional, such as one from Your Mechanic, to help you check your engine’s valve train with a leak down tester.
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Billing and parts question was sent to CS for the cost of parts and labor for valve train and related parts from a broken timing belt for a 1992 Acura Legend with a V6-3.2L engine.
Old belt was sqeeking, new belt does not but it slips off constantley. The old belt stays on though. Why is this?
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.
How does a mechanic know the timing belt is broken
ANSWER : Hello. I would need to know the specific engine to be sure, but since Honda does use interference type engines, it may be possible that damage has occurred if the timing belt has broken. Interference type engines use very tight valve to piston clearances. This yields increased engine performance, however, leaves the engine susceptible to contact and damage if the timing belt breaks. Checking to see if the belt is broken should be a simple matter of removing the timing covers to check the condition of the belt. While not common, it is still possible that the belt broke, even if it did not yet reach the recommended mileage. I would check the the belt to see if it has broken and go from there. If you need help with a timing belt repair, a certified professional from YourMechanic can go to your home or office to perform this service.
