What is a catalytic converter and how do you diagnose and repair it on GMC Sierra?

A catalytic converter is an emission control device that reduces certain pollutants. There are two types of converters: an oxidation catalyst that reduces hydrocarbons and carbon monoxide, and a reduction catalyst that reduces oxides of nitrogen. Vehicles are equipped with two three-way catalysts that can reduce all three pollutants. Whenever you raise the vehicle to service underbody components, inspect the converter for leaks, corrosion, dents, and other damage. The easiest way to check for a restricted converter is to use a vacuum gauge to diagnose the effect of a blocked exhaust on the intake vacuum. To remove the converter, raise the vehicle and place it securely on jack stands, disconnect the electrical connectors for the upstream and downstream oxygen sensors, remove all four sensors, remove the nuts at each of the upper flanges that secure the front exhaust pipe assembly to the exhaust manifold flanges, remove the nuts that secure the rear flange of the front exhaust pipe assembly to the rest of the exhaust system, and remove the front exhaust pipe assembly. To install the converter, coat the threads of the nuts and bolts with an anti-seize compound to facilitate future removal and tighten the nuts that secure the front exhaust pipe assembly to the exhaust manifold and to the rest of the exhaust system securely.

Genuine GMC Sierra Catalytic Converter

Cat. Converter

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77 Catalytic Converters found

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GMC Sierra CONVERTER ASM,3WAY CTLTC(W/EXH PIPE)
Part Number: 19420277
$2148.40 MSRP: $3032.88
You Save: $884.48 (30%)
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Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaces: 23268768, 25811714, 84053222, 84053221
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2012-2019 GMC Sierra | 1 TON CREW CAB, 2500 CREW CAB STANDARD BOX, 2500 REGULAR CAB, 3500 CREW CAB LONG BOX, 3500 CREW CAB ONLY, 3500 CREW CAB STANDARD BOX, 3500 DOUBLE CAB LONG BOX, 3500 REGULAR CAB, CREW CAB 1 TON, CREW CAB 1 TON 119.0, CREW CAB 2500 LONG BOX, CREW CAB 6'6" BOX 3/4 TON, CREW CAB 8' BOX 3/4 TON, DOUBLE CAB 2500 LONG BOX, DOUBLE CAB 2500 STANDARD BOX, EXTENDED CAB 1 TON, EXTENDED CAB 6'6" BOX 3/4 TON, EXTENDED CAB 8' BOX 3/4 TON, REGULAR CAB 1 TON, REGULAR CAB 3/4 TON | 8 Cyl 6.0L, 8 Cyl 6.0L Flex
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GMC Sierra CONVERTER ASM,3WAY CTLTC(W/EXH PIPE)
Part Number: 19420265
$1894.41 MSRP: $2965.42
You Save: $1071.01 (37%)
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaces: 23111625, 84362281
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2015-2018 GMC Sierra | 1500 CREW CAB, 1500 CREW CAB STANDARD BOX, 1500 DOUBLE CAB STANDARD BOX, 1500 REGULAR CAB LONG BOX, 1500 REGULAR CAB STANDARD BOX, CREW CAB 1/2 TON | 8 Cyl 6.2L
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GMC Sierra Three-Way Catalytic Converter with Exhaust Pipe
Part Number: 19420288
$1900.75 MSRP: $2975.40
You Save: $1074.65 (37%)
ADD TO CART
Product Specifications
- Other Name: CONVERTER ASM,3WAY CTLTC(W/EXH PIPE); Converter & Pipe, Converter
- Replaces: 23486656
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2016-2019 GMC Sierra | 1500 CREW CAB, 1500 CREW CAB STANDARD BOX, 1500 DOUBLE CAB STANDARD BOX, 1500 REGULAR CAB LONG BOX, 1500 REGULAR CAB STANDARD BOX, CREW CAB 1/2 TON | 8 Cyl 5.3L
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GMC Sierra CONVERTER ASM,W/UP 3WAY CTLTC (W/ EXH PIPE)
Part Number: 19420276
$2056.26 MSRP: $3066.58
You Save: $1010.32 (33%)
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaces: 20757674
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2014-2018 GMC Sierra | 1500 CREW CAB, 1500 CREW CAB STANDARD BOX, 1500 DOUBLE CAB STANDARD BOX, 1500 REGULAR CAB LONG BOX, 1500 REGULAR CAB STANDARD BOX, CREW CAB 1/2 TON | 6 Cyl 4.3L, 8 Cyl 5.3L
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GMC Sierra CONVERTER ASM,3WAY CTLTC(W/EXH PIPE)
Part Number: 19420284
$2123.31 MSRP: $3325.33
You Save: $1202.02 (37%)
Ships in 1-3 Business Days
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaces: 22948166
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2014-2016 GMC Sierra | 1500 CREW CAB, 1500 CREW CAB STANDARD BOX, 1500 DOUBLE CAB STANDARD BOX, 1500 REGULAR CAB LONG BOX, 1500 REGULAR CAB STANDARD BOX, CREW CAB 1/2 TON | 8 Cyl 6.2L
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GMC Sierra CONVERTER ASM,3WAY CTLTC (W/EXH MANIF PIPE)"KIT"
Part Number: 19418939
$1944.13 MSRP: $3152.45
You Save: $1208.32 (39%)
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaces: 15127418, 25904628, 25824120
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2007-2008 GMC Sierra | CREW CAB 1/2 TON, EXTENDED CAB 5'8" BOX 1/2 TON, EXTENDED CAB 6'6" BOX 1/2 TON, EXTENDED CAB 8' BOX 1/2 TON, REGULAR CAB 6'6" BOX 1/2 TON, REGULAR CAB 8' BOX 1/2 TON | 6 Cyl 4.3L, 8 Cyl 4.8L, 8 Cyl 5.3L, 8 Cyl 5.3L Flex, 8 Cyl 6.0L
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GMC Sierra CONVERTER ASM-3WAY CTLTC(W/EXH PIPE)
Part Number: 85542368
$1172.40 MSRP: $1743.03
You Save: $570.63 (33%)
Ships in 1-3 Business Days
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaced by: 86781749
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2019-2023 GMC Sierra | CREW CAB 5'8" 1/2 TON, CREW CAB 5'8" BOX 1/2 TON, CREW CAB 6'6" BOX 1/2 TON, EXTENDED CAB 6'6" BOX 1/2 TON, EXTENDED CAB 8' BOX 1/2 TON, REGULAR CAB 6'6" BOX 1/2 TON, REGULAR CAB 8' BOX 1/2 TON | 6 Cyl 4.3L, 8 Cyl 5.3L
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GMC Sierra CONVERTER ASM,3WAY CTLTC (W/EXH MANIF PIPE)"KIT"
Part Number: 19418932
$2562.62 MSRP: $3954.87
You Save: $1392.25 (36%)
Ships in 1-3 Business Days
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaces: 25824121
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2007-2008 GMC Sierra | CREW CAB 1/2 TON, EXTENDED CAB 5'8" BOX 1/2 TON, EXTENDED CAB 6'6" BOX 1/2 TON, EXTENDED CAB 8' BOX 1/2 TON, REGULAR CAB 6'6" BOX 1/2 TON, REGULAR CAB 8' BOX 1/2 TON | 6 Cyl 4.3L, 8 Cyl 4.8L, 8 Cyl 5.3L, 8 Cyl 5.3L Flex, 8 Cyl 6.0L
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GMC Sierra CONVERTER ASM,3WAY CTLTC (W/EXH MANIF PIPE) "KIT"
Part Number: 19420124
$972.66 MSRP: $1443.93
You Save: $471.27 (33%)
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe, Front Pipe
- Replaces: 15754088, 15755463, 10395213
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2001-2007 GMC Sierra | 1500 CREW CAB STANDARD BOX, 1500 EXTENDED CAB STANDARD BOX, CLASSIC 1500 CREW CAB STANDARD BOX, CLASSIC 1500 EXTENDED CAB STANDARD BOX | 8 Cyl 6.0L
View related parts
GMC Sierra CONVERTER ASM-3WAY CTLTC(W/EXH PIPE)
Part Number: 86781749
$1172.40 MSRP: $1743.03
You Save: $570.63 (33%)
Ships in 1-2 Business Days
ADD TO CART
Product Specifications
- Replaces: 84557805, 84520354, 19420299, 84655074, 85542368
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2019-2024 GMC Sierra | CREW CAB 5'8" 1/2 TON, CREW CAB 5'8" BOX 1/2 TON, Crew Cab 6'6" Box 1/2 Ton, CREW CAB 6'6" BOX 1/2 TON, EXTENDED CAB 6'6" BOX 1/2 TON, EXTENDED CAB 8' BOX 1/2 TON, REGULAR CAB 6'6" BOX 1/2 TON, REGULAR CAB 8' BOX 1/2 TON | 6 Cyl 4.3L, 8 Cyl 5.3L
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GMC Sierra CONVERTER ASM,3WAY CTLTC (W/EXH MANIF PIPE)"KIT"
Part Number: 19418941
$1974.70 MSRP: $3091.67
You Save: $1116.97 (37%)
Ships in 1-3 Business Days
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaces: 15905948, 20854454
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2009-2013 GMC Sierra | CREW CAB 1/2 TON, EXTENDED CAB 5'8" BOX 1/2 TON, EXTENDED CAB 6'6" BOX 1/2 TON, EXTENDED CAB 8' BOX 1/2 TON, REGULAR CAB 6'6" BOX 1/2 TON, REGULAR CAB 8' BOX 1/2 TON | 8 Cyl 4.8L, 8 Cyl 4.8L Flex, 8 Cyl 5.3L, 8 Cyl 5.3L Flex, 8 Cyl 6.0L, 8 Cyl 6.0L Flex
View related parts
GMC Sierra CONVERTER ASM,3WAY CTLTC (W/EXH MANIF PIPE)"KIT"
Part Number: 19418930
$1454.71 MSRP: $2274.06
You Save: $819.35 (37%)
Ships in 1-3 Business Days
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter
- Replaces: 25811716, 22751290
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2011-2015 GMC Sierra | 2500 REGULAR CAB, 3500 CREW CAB LONG BOX, 3500 CREW CAB ONLY, 3500 DOUBLE CAB LONG BOX, 3500 REGULAR CAB, CREW CAB 1 TON, CREW CAB 1 TON 137.0, CREW CAB 2500 LONG BOX, CREW CAB 8' BOX 3/4 TON, DOUBLE CAB 2500 LONG BOX, EXTENDED CAB 1 TON, EXTENDED CAB 8' BOX 3/4 TON, EXTENDED CREW CAB 1 TON 161.5, REGULAR CAB 1 TON, REGULAR CAB 3/4 TON, REGULAR CAB CHASSIS 1 TON 137.0, REGULAR CAB CHASSIS 1 TON 161.5 | 8 Cyl 6.0L Flex
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GMC Sierra CONVERTER ASM,3WAY CTLTC (W/EXH MANIF PIPE)"KIT"
Part Number: 19418958
$1501.93 MSRP: $2236.50
You Save: $734.57 (33%)
Ships in 1-3 Business Days
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaces: 20854457, 25904626, 25904629
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2007-2010 GMC Sierra | CREW CAB 1/2 TON, EXTENDED CAB 5'8" BOX 1/2 TON, EXTENDED CAB 6'6" BOX 1/2 TON, EXTENDED CAB 8' BOX 1/2 TON | 8 Cyl 6.2L, 8 Cyl 6.2L Flex
View related parts
GMC Sierra CONVERTER ASM,3WAY CTLTC (W/EXH MANIF PIPE)"KIT"
Part Number: 19418926
$1995.56 MSRP: $3134.37
You Save: $1138.81 (37%)
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaces: 15896590, 20854453
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2009-2013 GMC Sierra | CREW CAB 1/2 TON, EXTENDED CAB 5'8" BOX 1/2 TON, EXTENDED CAB 6'6" BOX 1/2 TON, EXTENDED CAB 8' BOX 1/2 TON, REGULAR CAB 6'6" BOX 1/2 TON, REGULAR CAB 8' BOX 1/2 TON | 6 Cyl 4.3L, 8 Cyl 4.8L, 8 Cyl 4.8L Flex, 8 Cyl 5.3L, 8 Cyl 5.3L Flex, 8 Cyl 6.0L, 8 Cyl 6.0L Flex
View related parts
GMC Sierra CONVERTER ASM,W/UP NOX CTLTC (W/ FLTR)
Part Number: 19420301
$959.22 MSRP: $1495.00
You Save: $535.78 (36%)
Ships in 1-3 Business Days
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaced by: 86534449
- Replaces: 84235516, 84189362, 84362533
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2017-2019 GMC Sierra | 2500 CREW CAB STANDARD BOX, 2500 REGULAR CAB, 3500 CREW CAB LONG BOX, 3500 CREW CAB ONLY, 3500 CREW CAB STANDARD BOX, 3500 DOUBLE CAB LONG BOX, 3500 REGULAR CAB, CREW CAB 2500 LONG BOX, DOUBLE CAB 2500 LONG BOX, DOUBLE CAB 2500 STANDARD BOX | 8 Cyl 6.6L Diesel
View related parts
GMC Sierra CONVERTER ASM,3WAY CTLTC (W/EXH MANIF PIPE) "KIT"
Part Number: 19420109
$891.85 MSRP: $1389.07
You Save: $497.22 (36%)
Ships in 1-3 Business Days
ADD TO CART
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe, Front Pipe
- Replaces: 10395214, 15755464, 15754087
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2001-2007 GMC Sierra | 1500 CREW CAB STANDARD BOX, 1500 EXTENDED CAB STANDARD BOX, CLASSIC 1500 CREW CAB STANDARD BOX, CLASSIC 1500 EXTENDED CAB STANDARD BOX | 8 Cyl 6.0L
View related parts
GMC Sierra 3 Way Catalytic Convertor Assembly
Part Number: 25782037
$986.16 MSRP: $1464.15
You Save: $477.99 (33%)
Product Specifications
- Other Name: Converter Assembly, 3Way Catalytic (W/ Exhaust Manifold P); Converter & Pipe
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2007-2008 GMC Sierra | CLASSIC 2500 CREW CAB LONG BOX, CLASSIC 2500 CREW CAB STANDARD BOX, CLASSIC 2500 EXTENDED CAB LONG BOX, CLASSIC 2500 EXTENDED CAB STANDARD BOX, CLASSIC 2500 REGULAR CAB, CLASSIC 3500 CREW CAB, CLASSIC 3500 EXTENDED CAB, CLASSIC 3500 REGULAR CAB, CREW CAB 1 TON, CREW CAB 6'6" BOX 3/4 TON, CREW CAB 8' BOX 3/4 TON, EXTENDED CAB 1 TON, EXTENDED CAB 6'6" BOX 3/4 TON, EXTENDED CAB 8' BOX 3/4 TON, REGULAR CAB 1 TON, REGULAR CAB 3/4 TON | 8 Cyl 6.0L
View related parts
GMC Sierra CONVERTER ASM,3WAY CTLTC (W/EXH MANIF PIPE) "KIT"
Part Number: 19419599
$1947.34 MSRP: $2903.47
You Save: $956.13 (33%)
Product Specifications
- Other Name: Catalytic Converter, Converter & Pipe
- Replaces: 15896591
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2011-2013 GMC Sierra | CREW CAB 1/2 TON, EXTENDED CAB 5'8" BOX 1/2 TON, EXTENDED CAB 6'6" BOX 1/2 TON, EXTENDED CAB 8' BOX 1/2 TON | 8 Cyl 6.2L Flex
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GMC Sierra Oxidation Catalytic Converter Assembly (W/ Exhaust Pipe)
Part Number: 22977171
$1621.52 MSRP: $2425.00
You Save: $803.48 (34%)
Product Specifications
- Other Name: Converter Assembly, Oxidation Catalytic (W/ Exhaust Pipe); Catalytic Converter, Converter & Pipe
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2015-2016 GMC Sierra | 2500 CREW CAB STANDARD BOX, 2500 REGULAR CAB, 2500 REGULAR CAB STANDARD BOX, 3500 CREW CAB LONG BOX, 3500 CREW CAB ONLY, 3500 CREW CAB STANDARD BOX, 3500 DOUBLE CAB LONG BOX, 3500 REGULAR CAB, CREW CAB 2500 LONG BOX, DOUBLE CAB 2500 LONG BOX, DOUBLE CAB 2500 STANDARD BOX | 8 Cyl 6.6L Diesel
View related parts
GMC Sierra CONVERTER ASM,3WAY CTLTC (W/EXH MANIF PIPE)"KIT"
Part Number: 19418942
$1421.32 MSRP: $2115.79
You Save: $694.47 (33%)
Product Specifications
- Other Name: Converter & Pipe
- Replaces: 20963621, 25782036
- Warranty: This genuine part is guaranteed by GM's factory warranty.
Fits the following Vehicles:
- 2007-2010 GMC Sierra | CLASSIC 2500 CREW CAB LONG BOX, CLASSIC 2500 CREW CAB STANDARD BOX, CLASSIC 2500 EXTENDED CAB LONG BOX, CLASSIC 2500 EXTENDED CAB STANDARD BOX, CLASSIC 2500 REGULAR CAB, CLASSIC 3500 CREW CAB, CLASSIC 3500 EXTENDED CAB, CLASSIC 3500 REGULAR CAB, CREW CAB 1 TON, CREW CAB 6'6" BOX 3/4 TON, CREW CAB 8' BOX 3/4 TON, EXTENDED CAB 1 TON, EXTENDED CAB 6'6" BOX 3/4 TON, EXTENDED CAB 8' BOX 3/4 TON, REGULAR CAB 1 TON, REGULAR CAB 3/4 TON | 8 Cyl 6.0L, 8 Cyl 6.0L Flex

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1-20 of 77 Results

GMC Sierra Catalytic Converter

The GMC Sierra Catalytic Converter efficiently transforms harmful gases generated by your vehicle into safer compounds and helps the truck pass smog inspections. Within the converter resides a ceramic or metallic honeycomb, which has been coated with platinum, palladium, and rhodium catalysts. Here, these gases pass through hot exhaust, and the carbon monoxide and unburned hydrocarbons oxidize to carbon dioxide and water. Furthermore, the nitrogen oxides are reduced to harmless nitrogen as well. Early GMC trucks applied a bead-filled Catalytic Converter that slowed gas flow through loose ceramic spheres. Now, however, Sierra models use a honeycomb style Catalytic Converter that offers greater surface area, faster reaction time, and less backpressure, which helps engine performance. The converter can fail as a result of engine misfires, overly rich fuel mixtures, coolant and oil leaks that overheat or coat the substrate, leading to clogs, rattles, warning lights, and restricted power. The case of the Catalytic Converter may crack due to debris from the road. If you want to maintain your efficiency and environmental compliance, make sure to keep your GMC engine properly tuned to protect the Sierra Catalytic Converter.

Each OEM GMC Sierra Catalytic Converter we offer is competitively priced and comes with the assurance of the manufacturer's warranty for the part. Furthermore, we guarantee the speedy delivery of your orders right to your doorstep. Our hassle-free return policy is also in place for your peace of mind.

GMC Sierra Catalytic Converter Parts Questions & Experts Answers

3 Way Catalytic Convertor Assembly
25782037
Q: What is a catalytic converter and how do you diagnose and repair it on GMC Sierra?
A:
A catalytic converter is an emission control device that reduces certain pollutants. There are two types of converters: an oxidation catalyst that reduces hydrocarbons and carbon monoxide, and a reduction catalyst that reduces oxides of nitrogen. Vehicles are equipped with two three-way catalysts that can reduce all three pollutants. Whenever you raise the vehicle to service underbody components, inspect the converter for leaks, corrosion, dents, and other damage. The easiest way to check for a restricted converter is to use a vacuum gauge to diagnose the effect of a blocked exhaust on the intake vacuum. To remove the converter, raise the vehicle and place it securely on jack stands, disconnect the electrical connectors for the upstream and downstream Oxygen Sensors, remove all four sensors, remove the nuts at each of the upper flanges that secure the front exhaust pipe assembly to the exhaust manifold flanges, remove the nuts that secure the rear flange of the front exhaust pipe assembly to the rest of the exhaust system, and remove the front exhaust pipe assembly. To install the converter, coat the threads of the nuts and bolts with an anti-seize compound to facilitate future removal and tighten the nuts that secure the front exhaust pipe assembly to the exhaust manifold and to the rest of the exhaust system securely.