How To Repair Catalytic Converter

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The catalytic converter, which is responsible for the cleanup of a vehicle exhaust, is a key component of a vehicle emission control system. When this slice malfunctions, the car will create boosted emissions, run more roughly, and have reduced fuel efficiency. While the cost of replacing a catalytic converter can be expensive, you can save money by doing it yourself with just a few manus tools and jack stands.

1. ane

   Park in a level place and jack the vehicle up at all iv wheels and support on jack stands. Replacing your vehicle's catalytic converter isn't quite like replacing a tire — yous'll demand to heighten the entire vehicle off of the footing, rather than just one corner. It's very of import to discover a level spot to do this maintenance on your car. If your car is not stable, you hazard serious injury or death if your jacks fail.

   • If you have access to a professional person-quality hydraulic lift and know how to safely use it, this is also an adequate way to lift your car when replacing the catalytic converter.

2. 2

   Allow the vehicle'due south exhaust to cool downwards. If your vehicle hasn't had an opportunity to absurd down later running, its exhaust system can yet be quite hot. To reduce the risk of painful burns, give your vehicle a chance to fairly absurd downwardly before working on it. Depending on your vehicle's exhaust system, this will usually exist a matter of merely a few minutes.

   • To test the heat of the exhaust system, put on a pair of heavy mechanic's gloves and gently brush the frazzle tube with the back of your hand. If y'all can't feel whatever heat, you may cautiously repeat this test without the glove.

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3. 3

   Locate the catalytic converter. Slide under the vehicle and locate the tubes of the exhaust organization, which should run all the way to your vehicle'south rear exhaust. The converter should not be terribly difficult to find — it will usually accept the form of a rectangular or rounded "box" in the middle of your exhaust organization. Some models can have a roughly cylindrical shape.^[1]

   • Bank check to run into whether the converter is bolted or welded to the rest of the exhaust arrangement at its connection points. Y'all may need to take it to an auto store to have it repaired if it has already been replaced and welded back into position, rather than bolted. You lot tin can still replace a welded converter if you have admission to a sawzall (or like tool) and a welding car and know how to safely use both, but these avant-garde tools are beyond the mastery of most amateur mechanics.

4. 4

   Remove the O₂ (oxygen) sensor from the catalytic converter. About modern catalytic converters are equipped with one or more oxygen sensors that monitor the efficiency of the car's exhaust system continuously. If your catalytic converter has an attached oxygen sensor, use an oxygen sensor socket and a ratchet wrench to disconnect it before proceeding.

   • When you lot're done, move the sensor out of your way and so that information technology doesn't interfere with the rest of the process.

5. 5

   If bolted, apply penetrating oil to the bolts. Catalytic converters that are bolted in tin sometimes have bolts that are rusted, partially-corroded, or "jammed" into their nuts. These bolts can be very tricky to remove, so loosen them up past applying a penetrating oil (available from near auto stores). Allow the oil to seep into the bolts and lubricate them for several minutes before attempting to remove them.

6. 6

   Remove the bolts at the back cease outset, so at the front. Use an accordingly-sized wrench to begin loosening all of the bolts before you start removing them. Once all of the bolts are loosened (just still attached), remove the "rear" bolts (those closest to the open finish of the vehicle's exhaust) earlier removing the "front" ones (those further abroad). Remove the converter when yous're done. You may have to back up the exhaust once the converter is removed.

7. 7

   Alternatively, for welded-in converters, cut the converter out. If your converter is welded into the rest of the frazzle organization, rather than bolted in, the only manner to remove it is to physically cutting information technology out of the pipes information technology's connected to. Most mechanics will utilise a sawzall or similar tool for this purpose. Cut forth (or near) the existing weld lines, then remove the converter subsequently it'due south cut gratuitous.

   • If you lot terminate and the converter won't seem to budge, you may want to utilize a hammer to knock it out of its place as long equally you take care not to impairment or rattle whatever other parts of the exhaust system (this can pb to harmful exhaust leaks down the route).^[two]

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1. ane

   Always defer to whatever included instructions. The instructions provided in this commodity are written for general cases of catalytic converter installation. Considering the exact office needed and the installation process can vary from vehicle to vehicle, the steps you lot'll need to replace your vehicle's converter may be different than the ones here. When in dubiety, e'er follow the instructions provided with your replacement part or consult the communication of a knowledgeable mechanic. Converters have a specific direction they should flow and have an pointer for direction of frazzle flow.

2. 2

   Insert any gaskets supplied with the new catalytic converter. Some converters, especially commodities-installed ones, will come with pocket-size, round gaskets that sit in the pipes connected to the converter to give the converter a snugger, more secure fit. If your replacement converter came with these gaskets, install them according to any provided instructions before proceeding.

3. 3

   Put the new catalytic converter in place. Next, hold the catalytic converter in the position where it will eventually be installed. Double bank check to brand sure it is pointed in the right direction (there should be an arrow indicating this) and that the correct side is facing downward.

   • Since it's tricky to work on the converter with one hand while you agree it in place with another, for the next few steps, it can be useful to enlist a willing friend to agree the converter in place while you lot work or use a stand to hold it up in place.

4. 4

   Finger-tighten nuts on the bolts. If your vehicle's catalytic converter was bolted in and your replacement converter has commodities holes that friction match your exhaust system'due south, installation is usually a cinch. To commencement, re-insert your bolts and use your easily to manually tighten them. This makes it easier to go all of the bolts to align correctly because the looseness gives you a modest degree of "jerk room" to brand minor adjustments as needed.

5. 5

   Tighten down all the bolts. Starting on the "front" end of the converter (the terminate further abroad from the vehicle's exhaust), tighten the bolts with a suitably-sized wrench. Proceed to the dorsum stop when you finish tightening the bolts on the front end.

   • You'll desire your bolts to be very tight. Most frazzle leaks are acquired past loose bolts, so making sure your bolts are extra tight at present tin save yous headaches in the future.^[iii]

6. half dozen

   Alternatively, weld the converter into identify. If you need to weld your converter into place, the process is somewhat more involved. You lot'll need a professional-class welding machine (such every bit a MIG welder) and the proper training and expertise required to employ 1 safely (or a friend who has these things). Don't attempt to weld your converter back into identify if you lot're not a competent welder — y'all could damage your vehicle or even injure yourself.

   • Weld your converter into identify past advisedly joining it to the exhaust arrangement pipes at either end. Be sure to create a secure, air-tight seal at each weld. If the pipes aren't wide enough, you may need to rut them up and flare them to make them fit. If your pipes don't quite reach 1 stop of your converter, you may need to weld an boosted extender pipe in. Sometimes you take to do a fractional weld so lower the exhaust to finish the tiptop part of the weld.
   • Exist sure to allow your welds to absurd to a safe temperature before proceeding.

7. 7

   Spiral the oxygen sensor back into place. If y'all originally removed one or more oxygen sensors to access your converter, supervene upon them at present. As y'all do, check to brand certain that the attached wiring is secure and is non frayed or damaged — this can lead to inaccurate readings and even false "check engine" lights.

8. 8

   Double-check your work. At this betoken, if you've done everything correctly, you're basically done. Accept the opportunity to brand sure one terminal time that the catalytic converter is connected correctly and there are no gaps or leaks at either of the connections or the oxygen sensor. If you lot bolted your converter in, make sure all of your bolts tight. If you lot welded information technology in, make certain your welds are sturdy and airtight.

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1. one

   Check for exhaust leaks. Once you've installed a new catalytic converter, one thing you lot'll want to do immediately is double-bank check to make sure there aren't any leaks in the exhaust organization on either side of it. Depending on where it is, an exhaust leak can cause a variety of problems for your vehicle, including reduced fuel efficiency and long-term damage.^[iv]

   • In that location are several ways to observe an exhaust leak. I is to merely exist observant while you lot drive — if your motorcar sounds louder than normal when information technology runs or seems to "rumble" more, you may take a leak.^[5] You tin too check for leaks by jacking your car up, starting information technology in park, and carefully moving a lit candle along the length of the exhaust tubing. Leaks which are invisible to the eye should cause the flame to waver or blow out.

2. two

   Measure out dorsum-pressure in the frazzle system. One problem that can occur in faulty catalytic converters is that they tin can become "backed up" with soot, debris, and other exhaust byproducts or broken apart inside the converter. In this case, the engine's ability to rid itself of exhaust is hampered, which can cause a vehicle's fuel efficiency to collapse and can even crusade the engine to stall in severe cases.^[6] Luckily, performing a backpressure test is simple — but screw a pressure judge into the oxygen sensor'south hole earlier the converter in the exhaust manifold in most vehicles. The force per unit area reading should be less than one.25 psi when the vehicle's engine is running at ii,000 RPMs.^[seven]

   • The worse the congestion is, the higher the pressure level reading can be. Very bad backpressure readings can approach 3 psi.

3. iii

   Perform a mallet exam for old converters. If your car's converter is onetime and worn, ane simple test can tell whether information technology needs to be replaced very quickly. Simply grab a rubber mallet (or similar tool) and give the converter a firm hit. If you hear any sort of rattling, your converter needs to be replaced — this indicates that the metallic catalyst within has begun to corrode and crumble.

   • However, if yous don't hear a rattle, this doesn't necessarily hateful that your converter works well. There may nevertheless be other problems with information technology. To be clear, this examination can only tell you if you have a bad converter, not if y'all have a skilful one.

4. 4

   Consider more advanced tests. Catalytic converters tin be tricky parts — if you lot're in doubt about whether or non yours is operation properly even later performing the tests to a higher place, don't hesitate to take information technology to a mechanic or specialist. These professionals volition have access to the type of equipment that can exist used to perform more than advanced tests, like delta temperature tests, oxygen storage tests, and CO_ii tests.

   • Most automobile shops that offer smog testing volition be able to perform these sorts of emissions tests.

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• A flooring jack is far superior to the jack that came with your car.

• Before doing any electrical welding make certain the battery is asunder.

• A rotten egg or sulfur odour coming from your car is a sign of a bad converter.

• Clear all estimator codes later on the converter is replaced and monitor the O2 sensors for any problems.

• Be sure you accept asunder the positive battery cablevision as a precaution against accidental grounding of the electrical system before y'all crawl under the car.

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• Make sure the exhaust is cool earlier working on it to prevent burns.

• Always vesture safety glasses and gloves while working on the exhaust system under your vehicle.

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Things You'll Need

• New catalytic converter
• Oxygen sensor socket
• Various sized sockets for your vehicle
• 3/viii inch ratchet with short extension
• Jack stands
• Floor jack
• Penetrating oil

About This Article

Article Summary X

To replace a catalytic converter, start past jacking the car up so that you can work underneath information technology. Then, locate the catalytic converter at the center of your frazzle system and remove the oxygen sensor with a ratchet wrench. Next, unscrew the bolts at the back of the converter, followed by the ones at the front, and remove it from the motorcar. Subsequently you've removed the erstwhile converter, put the new ane in its place and tighten all the bolts to secure it to the machine. Finally, supercede the oxygen sensor and check all the connections to make sure they're closed. For advice from our Automotive co-writer on how to replace a catalytic converter that'due south welded in place, read on!

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Source: https://www.wikihow.com/Replace-a-Catalytic-Converter

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