What are Engine Manifold Leaks?

Engine manifolds are gaskets that provide a mixture of air and fuel to the cylinders of the engine. Leaky engine manifolds suck outside air in, instead of expelling air out; as well as leaking engine coolant out of the vehicle.

This disrupts the combustion process driving the engine, thereby causing many complications (described below). The reliable performance of engine manifolds is therefore essential to the smooth operation of the entire vehicle.

Signs & Symptoms of Engine Manifold Leaks

Vehicles affected by engine manifold leaks will typically experience the following:

• Engine misfires
• Difficulty starting
• Slower acceleration
• Reduced fuel efficiency
• Backfires
• Overheating engine
• Increased emissions
• Coolant leaks outside the engine manifold
• Milky engine oil consistency
• Engine light on
• Noisy engine
• Exhaust fumes in the car

Causes of Engine Manifold Leaks

The following key reasons commonly cause engine manifold leaks:

Cracked Engine Manifold

Engine manifolds are subject to high stresses, temperature changes, pressure changes and dust particles. This can lead to wear and tear over time, causing cracks to appear in the gasket. These cracks, if left untreated or undiagnosed, can lead to the manifold leaking – ultimately leading to unexpected breakdowns and premature failure.

Worn-Out Bolts and Studs

The same thermal and pressure changes that can crack the engine manifold can also wear out the bolts, studs and screws connected to the manifold. Similarly, corrosion can act in the same way. Damaged bolts and studs can lead to an ineffective seal around the manifold gasket, leading to leaks.

Leaky Engine Coolant

The coolant used within the engine manifold can affect the likelihood of a leak.

Coolants that attract more dust and debris without washing them out, and aren’t formulated to be corrosion-resistant, can increase the chances of a leak. This is due to the increased effects of wear from the dust particles onto the manifold gasket, as well as the formation of corrosion weakening the manifold surfaces.

Best Engine Solutions to Avoid Manifold Leaks

Here at Antala, we provide a range of adhesives, sealants and lubricants that can be used to optimise the performance of engine manifold gaskets. Due to the issue being leak-based, silicones and anti-friction coatings can provide reliable protection to prevent further leaks.

Benefits of using DOWSIL silicone sealants and Molykote lubricants for engine manifold applications include:

• Ability to sustain extreme temperatures and thermal changes
• Ability to sustain high pressures changes
• Reduced wear and friction – long-term protection
• Resistance to harsh chemicals, steam, and moisture
• Non-corrosive to metals
• Non-oxidising
• Extended lubricant life due to low volatility and outgassing
• Non-damaging to plastic or elastomers – broad elastomeric compatibility
• Non-hazardous and non-toxic
• Minimal environmental footprint; no damage to the atmosphere or ozone layer
• Both oils and greases are suitable for automated spray application

As a result of these benefits, manufacturers of engine manifolds can prevent leaks, reduce maintenance and repairs, and improve safety, efficiency and quality.

Silastic RBL-9694-45M is a two-part liquid silicone rubber that has successfully been used for the compression sealing of engine manifold gaskets. It provides high tear resistance and long-term stability over a wide temperature of -50°C to +200°C. In addition, it offers good adhesion on a variety of substrates.

DOWSIL 7091 is a silicone sealant and adhesive that can be used for the sealing of engine manifold gaskets without on-line pressure check. It is used as a formed-in-place gasket (FIPG) material, and is stable and flexible from -55°C (-67°C) to +180°C (+356°C).

DOWSIL Q3-1566 is a high-temperature-resistant silicone sealant that can be used for the sealing of engine manifold gaskets without on-line pressure check. It remains flexible and stable from -50 to 275°C and provides good adhesion to a wide range of substrates.

Molykote D-7620 is an anti-friction coating that has successfully been used on cylinder head gaskets and exhaust manifold gaskets of combustion engines. It is suitable for highly stressed sliding areas with low sliding speeds, oscillating movements or intermittent operations. It provides permanent lubrication at high temperatures and also where oils and greases cannot be used.

Molykote D-6900 is an anti-friction coating that has successfully been used on engine manifold gaskets. It offers micro-sealing properties (fulfilling EURO 6 emission specifications up to 600°C) and prevents welding of metal/metal combinations at high temperatures. It provides high resistance to motor oil and coolant and high load-carrying capacity.

View our full range of automotive engine & powertrain solutions to determine the most appropriate solution for your application.