2013 Nissan Altima Valve Cover Gasket

The 2013 Nissan Altima, a staple in the mid-size sedan market, relies on a robust engine for its performance. A critical, yet often overlooked, component of that engine is the valve cover, and consequently, its associated gasket. This article delves into the purpose, function, potential failure points, and replacement nuances of the 2013 Nissan Altima's valve cover gasket. While seemingly simple, understanding its role can significantly improve your understanding of internal combustion engine mechanics.

The Role of the Valve Cover and Gasket

To appreciate the gasket, one must first understand the valve cover's purpose. The valve cover, typically made of aluminum or plastic, serves as a protective shield for the engine's valve train. This valve train includes components such as the camshaft(s), rocker arms (or direct acting tappets), and valve springs. These components orchestrate the opening and closing of the intake and exhaust valves, controlling the flow of air and fuel into the cylinders and the expulsion of exhaust gases.

The primary function of the valve cover is to prevent oil from splashing out of the engine while these components are in motion. The valve train is constantly lubricated with engine oil, which is sprayed and splashed around to reduce friction and dissipate heat. Without the valve cover, this oil would be flung throughout the engine compartment, leading to a significant loss of lubrication, a massive mess, and potentially catastrophic engine damage.

The valve cover gasket is the essential intermediary between the valve cover and the cylinder head. Its function is to create a tight, leak-proof seal. Typically made of rubber, silicone, or a composite material, the gasket conforms to the irregular surfaces of both the valve cover and the cylinder head. This seal prevents oil from escaping the engine and contaminants from entering.

Understanding the Engine and Valve Train of the 2013 Altima

The 2013 Nissan Altima typically came with two engine options: a 2.5-liter four-cylinder engine (QR25DE) and a 3.5-liter V6 engine (VQ35DE). While the specific configuration and materials might differ slightly between the two engines, the fundamental principle of the valve cover and gasket remains the same.

Both engines are of the overhead camshaft (OHC) design. The 2.5L QR25DE is a Dual Overhead Camshaft (DOHC) engine, meaning it has two camshafts positioned above the cylinder head, one for the intake valves and one for the exhaust valves. The 3.5L VQ35DE is also a DOHC engine, but with two banks of cylinders in a V configuration, each bank having its own set of camshafts.

The complexity of the valve train directly impacts the shape and design of the valve cover and gasket. DOHC engines generally have more complex valve covers to accommodate the additional camshaft. Furthermore, the gasket design must account for the bolt pattern securing the valve cover to the cylinder head and any other components housed under the valve cover, such as spark plug tubes or coil packs. Because of this, the valve cover and gasket design will be significantly different between the inline four QR25DE and the V6 VQ35DE. Both, however, are designed to withstand high heat, constant oil exposure, and the vibrations of the running engine.

Symptoms of a Failing Valve Cover Gasket

A failing valve cover gasket can manifest in several ways. Recognizing these symptoms early can prevent more severe engine problems.

Oil Leaks: This is the most obvious sign. You might notice oil puddles under your car, particularly after it has been parked for a while. The oil leak could be visible around the valve cover itself, dripping down the engine block.
Burning Oil Smell: Oil leaking onto hot engine components, such as the exhaust manifold, will produce a distinct burning smell. This smell is often strongest after the engine has reached operating temperature.
Low Oil Level: A leaking valve cover gasket will gradually lead to a drop in the engine's oil level. Regularly checking your oil level is crucial for maintaining engine health.
Smoke from the Engine Bay: In severe cases, significant oil leakage onto hot engine parts can cause smoke to billow from the engine bay. This is a serious sign and requires immediate attention.
Engine Misfires: If oil leaks into the spark plug wells (especially common on engines with integrated spark plug tube seals in the valve cover gasket), it can foul the spark plugs, causing engine misfires.

It's important to note that these symptoms can also indicate other engine problems, so proper diagnosis is crucial.

Causes of Valve Cover Gasket Failure

Valve cover gaskets typically fail due to a combination of factors:

Age and Deterioration: Over time, the gasket material can harden, crack, and lose its elasticity due to heat cycling and exposure to engine oil. This natural degradation is the most common cause of failure.
Improper Installation: Over-tightening the valve cover bolts can crush the gasket, leading to premature failure. Conversely, under-tightening can result in an incomplete seal. Proper torque specifications are critical.
Oil Contamination: Contaminated engine oil can accelerate the degradation of the gasket material. Regular oil changes with high-quality oil are essential for maintaining gasket health.
Extreme Temperatures: Repeated exposure to extreme temperatures can stress the gasket material, causing it to become brittle and prone to cracking.

Valve Cover Gasket Replacement: A Conceptual Overview

Replacing the valve cover gasket on a 2013 Nissan Altima, while not overly complex, requires a methodical approach and some basic mechanical knowledge. Here's a general overview of the process (always refer to the vehicle's service manual for specific instructions and torque specifications):

Preparation: Gather necessary tools (socket set, torque wrench, screwdrivers, scraper, cleaning supplies), a new valve cover gasket, and optionally, new valve cover bolts if recommended. Ensure the engine is cool to prevent burns.
Removal: Disconnect the negative battery terminal. Disconnect any components attached to the valve cover, such as ignition coils, breather hoses, and wiring harnesses. Carefully remove the valve cover bolts in a specific sequence (usually from the outside in a crisscross pattern) to prevent warping the valve cover.
Inspection and Cleaning: Carefully remove the old gasket and inspect the valve cover and cylinder head surfaces for any damage or debris. Thoroughly clean both surfaces with a scraper and solvent to ensure a clean, smooth mating surface. Check the valve cover for cracks or warping.
Installation: Install the new valve cover gasket, ensuring it is properly seated in the valve cover groove. Apply a small amount of RTV sealant to specific areas (usually corners or seams) as indicated in the service manual.
Reassembly: Carefully reinstall the valve cover, tightening the bolts in the correct sequence and to the specified torque. Over-tightening is a common mistake that can damage the gasket and valve cover. Reconnect all previously disconnected components.
Verification: Reconnect the negative battery terminal. Start the engine and check for any oil leaks around the valve cover. Monitor the oil level for the next few days to ensure there are no hidden leaks.

Important Considerations:

Torque Specifications: Always use a torque wrench and adhere to the manufacturer's specified torque values for the valve cover bolts.
Gasket Type: Ensure you are using the correct type of gasket for your engine. Using the wrong gasket can lead to leaks.
Surface Preparation: Thoroughly cleaning the mating surfaces is crucial for a proper seal.
Spark Plug Tube Seals: If your engine has spark plug tube seals integrated into the valve cover gasket, inspect them carefully and replace them if necessary.
Valve Cover Condition: Check the valve cover for cracks, warping, or other damage. A damaged valve cover may need to be replaced.

While this overview provides a general understanding, it's crucial to consult the vehicle's service manual for detailed instructions and specific torque specifications. If you are not comfortable performing this repair yourself, it's best to seek the assistance of a qualified mechanic. Replacing the valve cover gasket is a critical maintenance task that helps to ensure the longevity and performance of your 2013 Nissan Altima's engine.