Jeep Grand Cherokee Catalytic Converters

3 Simple Tips to Keep the Jeep Grand Cherokee Catalytic Converter Running in Good Condition

The catalytic converter of your Jeep Grand Cherokee does not require periodic maintenance compared to other parts of your SUV. In most cases, the only time you'll handle this component is when it's broken and needs replacement. However, there are several ways you can do to keep the Jeep Grand Cherokee catalytic converter running in top condition.

• Do not let the engine overheat.

Running the engine to the point of overheating will do more than just damage it and the radiator. An overheated engine leads to extremely hot exhaust gas that, once reaches the catalytic converter, can melt the ceramic catalyst substrate and its matting, rendering the converter inoperable and potentially blocking the exhaust from leaving the system. Once the temperature gauge in your Jeep starts to hit the high notes, let the engine cool down immediately, and have the engine, radiator, and the catalytic converter checked by a professional mechanic.

• Keep the silicone-based sealant or lubricants away from the catalytic converter.

Typically used to seal the exhaust manifolds and headers, silicone sealant or lubricant will vaporize into a gaseous form when exposed to high temperature. And once this silicone gas reaches the catalytic converter, it can contaminate the oxygen sensor, causing incorrect readings that can lead to dirtier emissions, decreased fuel efficiency, and higher operating temperatures. As a rule of thumb, do not apply silicone sealant, silicone-based grease or similar products on or near the exhaust side of the engine. Before you apply anything on the exhaust components, make sure to double check the label first.

• Change the engine oil periodically.

Many car owners make the mistake of letting the engine oil cook to a crisp, but once it goes bad it can cause additional wear to the engine valves and piston rings. And once this happens, the oil will mix with the exhaust gas and damage the catalyst upon reaching the converter. A common sign of engine oil contamination is thick, bluish smoke from the exhaust, so once you notice this happening in your Grand Cherokee, have it inspected by a mechanic. In most cases, the engine will go through a compression or "leakdown" test to confirm if engine oil is seeping through the combustion chamber.

Diagnosing a clogged or damaged Jeep Grand Cherokee catalytic converter usually involves a mechanic and a professional diagnostic tool, but there are ways for you to determine whether that problem in your SUV is coming from your cat con. Catalytic converter problems come in many forms; below are the most common signs and tips on how to troubleshoot them:

Engine misfires

One of the many causes of a misfiring engine is a melted catalyst. Very hot exhaust gas from an overheated engine and a rich fuel mixture can melt the catalyst substrate and matting of the converter, and this melted, gooey mess can clog the exhaust pipes and prevent exhaust gas from escaping. If you suspect that your Jeep's catalytic converter has melted, have someone shine a light on the carburetor while you press on the accelerator. If fuel vapor appears over the top of the carburetor, it's very likely that the catalytic converter is damaged and needs to be replaced.

Engine stalls or jerks

Another sign that points to a damaged catalytic converter is stalling or jerking of the wheel whenever you step on the gas. This is due to "backpressure", wherein the exhaust gas is trapped in front of the catalyst. The trapped gas then returns to the engine, preventing it from breathing, thus resulting in stalling. So once this happens on your SUV, make sure to inspect your catalytic converter as soon as you can.

Blue smoke coming out of the exhaust

Thick blue smoke indicates that engine oil has contaminated the fuel mixture. When this happens, engine oil will actually accelerate wear of the engine valves and piston rings. It will also seep into the combustion chamber and mix with the fuel and air mixture. And once the tainted exhaust gas reaches the catalyst, it will coat and damage the substrate and result in a noticeable bluish smoke.

Poor fuel economy

Once the catalytic converter starts to fail, it will cause the oxygen sensor to issue incorrect readings, which in turn leads to the engine burning more fuel than necessary. So if you find yourself spending more on gas than normal, have the converter looked at as soon as possible.