Rattling on a 2005 Subaru Forester

I've got a Subaru Forester 2.5, 2005. It's been rattling. I thought it was coming from the muffler. But I've heard it coming more from the engine area. Any places I should check?
Experienced mechanics share their insights in answering this question :
Yes, the catalytic converters would often rattle. Catalytic converters look like mufflers but they are not. They have platinum inside these ceramic pieces and the hot air goes through them and burns hydrocarbon. What happens is, the ceramic parts start to break and then they rattle and go against the metal parts of the outside shell. Take a little hammer and gently hit the catalytic converter. If it rattles, then those are the metal pieces.

You could also look at the heat shields around it because a lot of the exhaust parts have heat shields that are welded on and stamped. A lot of times, those little spot welds break and start to rattle and you’ve got to re-weld those things back on again. If you’d like to have the faulty part verified by a professional, have a technician from YourMechanic inspect your car’s rattling noise for you.

How to Identify and Fix Common car Problems ?

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Rattling Noise – Once your catalytic converter becomes older or damaged from fuel mixtures, the honeycombs on the inside can begin to collapse and/or break apart which will cause a rattle to occur.
What does a bad catalytic converter sound like? Often, a clogged catalytic converter sounds like a rattling noise is coming from under your vehicle and engine when you`re starting, idling or driving. Excess heat or damage in the converter can break apart the honeycomb materials, resulting in the rattling noise.
The most common reasons a Subaru Forester has a rattling noise are the ball joints, struts or strut mount, or a problem with the sway bar links.
Clean the Catalytic Converter With Sodium Hydroxide

If your car`s catalytic converter is making an irritating noise, try cleaning it with sodium hydroxide. This method will remove built-up carbon and other materials that may be causing the noise.

Broken Muffler: The Cause

There are three common reasons that you will encounter your muffler rattling: a bad bracket, connector, or rubber hanger. Over time, these components corrode and weaken, which causes the muffler to shift and rattle as you drive around Gardner.

A loose bracket, rubber hanger or connector, or one that is badly corroded, can allow a muffler to rattle as the exhaust pipe bangs against another part of your vehicle when you accelerate or drive on bumpy roads, or even when you first start the car and it`s stationary and idling.
Odd sounds are a symptom of a bad torque converter

When you begin to hear unusual noises, you should take notice. Rattling is one sound you want to be aware of. If you hear odd rattling sounds when you accelerate, this might be a symptom of a bad torque converter. The same can be true of whirring noises.

If you hear a rattling noise while driving, the first step is to not ignore it. The sounds and vibrations coming from your vehicle could be signs of a serious mechanical issue. Seek help from a professional who can find the source of the noise before any further damage is done.
Your Subaru will have a recommended octane rating. If you fill it up with gas with an octane rating that`s below the manufacturer`s specs, you may hear a knocking or pinging noise coming from the engine.
The noise is normal, and is created by engine pulses being amplified through the light-off converters. Do not replace the converters unless loose internal components are found.
As we just mentioned, a missing catalytic converter will make your engine very loud. In fact, the engine will roar. You may not have realized this but the catalytic converter helps to muffle some of the engine and exhaust noise. Now that the converter is missing, your engine will be louder than normal.
While you can technically drive with a broken exhaust, it`s neither safe nor legal and poses a number of issues when you`re out on the road. Whether your exhaust is simply cracked, is partially hanging off or has fallen off completely, it`s an important part of your vehicle which needs your immediate attention.
Listen for a rattling sound coming from underneath your vehicle while it`s running or when you rev the engine to determine if the converter is the issue. Rattling could also be a sign that parts of your exhaust system are loose and need to be tightened.
Driving with A Failed Catalytic Converter

If you`re noticing slow powertrain performance, reduced acceleration, a smell of rotten eggs or sulfur from the exhaust, dark exhaust smoke, or extreme heat from under the vehicle, these are symptoms of a clogged Catalytic Converter, and it should be replaced quickly.

Listen for a rattling sound coming from underneath your vehicle while it`s running or when you rev the engine to determine if the converter is the issue. Rattling could also be a sign that parts of your exhaust system are loose and need to be tightened.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Rattling on a 2005 Subaru Forester
ANSWER : Yes, the catalytic converters would often rattle. Catalytic converters look like mufflers but they are not. They have platinum inside these ceramic pieces and the hot air goes through them and burns hydrocarbon. What happens is, the ceramic parts start to break and then they rattle and go against the metal parts of the outside shell. Take a little hammer and gently hit the catalytic converter. If it rattles, then those are the metal pieces.

You could also look at the heat shields around it because a lot of the exhaust parts have heat shields that are welded on and stamped. A lot of times, those little spot welds break and start to rattle and you’ve got to re-weld those things back on again. If you’d like to have the faulty part verified by a professional, have a technician from YourMechanic inspect your car’s rattling noise for you.

Recommendation of Subaru Forester
ANSWER : Hello. There is a big concern with the air bags on this car. If the car is, or even "was", equipped with a Takata airbag, I wouldn’t consider purchasing it due to the Subaru Recall. Even if the airbag was "replaced", press coverage suggests that Takata supplied airbags are being used as replacements. Furthermore, airbags replaced in the field, that is outside of factory conditions represent a problematic circumstance. You may not even "reach" this issue of the airbag though, since Consumers Reports clearly reports that the reliability of the engine and brake system on this year, make, and model have "a higher rate of problems than the average model."

There are numerous recalls and service campaigns including the 2009 2.5-liter models in PZEV states that had to have the catalytic converter replaced. The 2009 model-year 2.5 XT versions were recalled to replace the oil supply pipe due to the possibility of deformation, and the 2009-13 Foresters were recalled so the dealer could inspect and replace rusted brake lines. 2009 models that have difficulty fueling after driving in snow need a modification to prevent an EVAP hose from freezing, and the 2009-13 manual models might need adjustment of the clutch switch if the hill-start assist is inoperative.

If you are looking for a used vehicle consult Consumer Reports which has already done exhaustive testing and surveying and compiled a list of acceptable used vehicles. In all events, any used vehicle needs to be thoroughly inspected by someone who knows how to read the telltale clues that represent problems or concealed damage. As a used car buyer, really, a principle issue facing buyers at the moment is this fact that TENS of millions of used vehicles out there on the road were essentially equipped with pipe bombs (Takata inflators) and you will have to stay away from that entire population of vehicles. Personally, I would not buy a used car that ever contained a Takata inflator, whether replaced or not.

Just bought a used Forester that started rattling when I’m not accelerating and the wheel is straight. Any ideas on what it could be?
ANSWER : Hey there. The most common source of rattles on Subaru’s are the exhaust heat shields. They can rattle under all sorts of random circumstances. Whenever you turn, accelerate, let off the gas or brake, the motor experiences torque that is dampened by the engine mounts so the passengers won’t feel these vibrations. This torquing will affect the exhaust as much as any other component on the car. Checking for exhaust shield rattles is fairly simple. Use a soft mallet hammer to tap on the shields to see if it rattles. If it does, repairing this is more challenging than locating it. It’s a creative process that can only be decided in person. Of course, you will need to get under that car to access all of the shields.

Other than the exhaust shields, it could be a dust shield on the brakes or a sway bar end link. Both of these are far less common as determined by your description of your symptoms. If it is a sway bar end link, it will rattle most often when you go over bumps. If it is the brake dust shield, you will need to remove the wheel to see if the shield is loose.

If you need further help having this done, a certified professional from YourMechanic can come to your car’s location to diagnose the rattling noise so that this can be corrected.

I hear a rattling noise when my truck is parked. But when I drive it the noise stops. It sounds like a metal ball is rattling around.
ANSWER : Often, some exhaust components like heat shields or hangers may rust or become loose and rattle over time and is pretty common for the type of sound you’re describing. If you are not experiencing any drivability concerns, the rattle may be from something small. The best thing to do would be to have an experienced technician like one from YourMechanic take a close look around the vehicle under the conditions that makes the noise the most prominent so the technician may offer a more personal diagnosis.

Rattling noise upon starting and then louder rattling at idle if load is placed on engine such as A/C
ANSWER : Hi there. Given your mileage and your maintenance of the idler pulley, your problem is likely worn/weak hydraulic lifters (or other valve train wear) or the timing gear set. Starting the engine briefly (less than 30 seconds) without the serpentine belt attached, will eliminate noises from all accessories if the problem is with one of them. I would recommend having the engine inspected in person by a professional so that the rattling noise can be diagnosed and properly corrected.

I am looking at a 2000 Subaru Forester for sale that needs "the timing belt repaired". Advice?
ANSWER : Hello, thank you for writing in. The timing belt keeps the camshaft and the crankshaft running together. Without it the vehicle will not run correctly. If the timing belt is on the vehicle and is in poor condition, you may get a few more miles out of it. However this leaves you vulnerable to a breakdown, which is of course a major safety concern. There is no way to repair the belt, it has to be replaced much like the drive belt which powers your accessories. Keep in mind, when a timing belt breaks while the vehicle is driving, there can be major damage done to the engine. If this has already occurred on the vehicle, you should find out if they have inspected for that further damage. Most of the cost for the repair work is labor cost. The timing belts are hard to get to, and have to be done perfectly the first time. For help repairing the timing belt, or to get another quote, contact our service department.

I have a 2014 Subaru Crosstrek with 96,000 miles. Less than a year ago, I had to get a new transmission (and Subaru covered most o
ANSWER : Although the CV axles are a component that it is a ’good idea’ to replace if you are replacing a transmission, it is also not necessarily required to resolve the issues the transmission may have had as they simply transfer power from the transmission to the wheels. With that being said, it is possible that the CV axles you have oin the vehicle are the original axles to the vehicle and were not replaced when the transmission was replaced. This is especially true if someone else covered most of the cost. They were likely trying to repair/replace only what was absolutely necessary as it was a loss on their part either way. CV axles should last for tens of thousands of miles but can fail at random times. Consider YourMechanic for a suspension inspection to have a qualified professional give you a second opinion on the condition of your CV axles.

My car is making a loud rattle sound when idling and in neutral
ANSWER : There are several causes for the engine to rattle while idling. With your car, the heat shield or an under engine shield is most likely. The other causes are the AC compressor clutch, idler pulley, or belt tensioner. The heat shields are used between the exhaust and the underside of the vehicle to keep the vehicle cool and the heat from the exhaust directed out of the tailpipe. When the heat shields become loose, they can make a flapping noise when the vehicle is moving. To verify this, a qualified technician, like one from YourMechanic, will be able to diagnose the rattle and replace your heat shield if necessary.