Best Upper Cylinder Lubricant: Technical Comparison

As a career long engineer (formerly employed by Ford) with decades of experience testing vehicles and analyzing lubricants, I've seen firsthand the impact that proper lubrication has on engine performance and longevity. In this comprehensive guide, I'll break down everything you need to know about upper cylinder lubricants (UCLs) and compare the top products on the market to help you make the best purchasing decision possible.

What Are Upper Cylinder Lubricants?

Upper cylinder lubricants are fuel additives designed to provide additional lubrication to the upper portions of the engine cylinders, particularly the area where the piston rings meet the cylinder walls. Modern fuels, especially those with higher ethanol content, can lack the natural lubricity that older fuels provided, making UCLs increasingly important for engine protection.

The Engineering Behind UCLs

From my experience, I can tell you that the upper cylinder area experiences some of the most severe conditions in just about any internal combustion engine:

• Temperatures exceeding 500°F (260°C)
• Minimal oil film protection compared to lower engine areas
• Direct exposure to combustion byproducts
• High-speed metal-to-metal contact
• High susceptibility to corrosion (especially due to the prevalence of water-absorbing ethanol in fuel)

Upper cylinder lubricants typically claim to improve fuel lubricity which is defined as the ability of a fuel to reduce friction between two surfaces in relative motion, therefore reducing wear and scuffing.

Fuel system components like pumps and injectors normally rely entirely on the fuel for ensuring correct lubrication. Upper cylinder lubes can help better protect fuel system components from wear, provide that lacking upper cylinder lubrication, reduce piston ring & cylinder wear, which combined, can increase engine compression, horsepower, and fuel economy.

When Should You Use an Upper Cylinder Lubricant?

Based on my engineering background and extensive testing experience, I recommend considering a UCL in these situations:

1. ‍Vehicles regularly using ethanol-blended fuels (E10, E15): Ethanol-blended fuels provide significantly less lubricity than traditional gasoline. This reduced lubricity can lead to accelerated wear on fuel system components and upper cylinder areas, making supplemental lubrication particularly beneficial.
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2. High-mileage engines showing signs of compression loss: As engines accumulate miles, the seal between piston rings and cylinder walls naturally deteriorates. Through compression testing of numerous high-mileage engines, I've seen how quality UCLs can help improve ring sealing and restore some lost compression, particularly in engines over 100,000 miles.
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3. Vehicles that make frequent short trips: In short-trip driving, engines often don't reach full operating temperature, leading to increased fuel dilution in the oil and reduced upper cylinder lubrication. I've observed this issue extensively in fleet testing, where vehicles in urban delivery service showed accelerated upper cylinder wear compared to highway-driven vehicles.
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4. Direct-injection engines prone to carbon buildup: Modern direct-injection engines spray fuel directly into the combustion chamber, eliminating the cleaning effect that port fuel injection provided to intake valves. From my engineering experience, I've seen how UCLs can help minimize carbon buildup and maintain better combustion chamber cleanliness.
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5. Performance vehicles operating under high loads: Engines under high performance demands experience significantly higher temperatures and pressures in the upper cylinder area. A quality UCL provides an additional layer of protection during these extreme operating conditions, helping to prevent accelerated wear.
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6. Older vehicles designed before modern fuel standards: Engines manufactured before the widespread adoption of ethanol-blended fuels were designed with different fuel properties in mind. Based on my engineering analysis, these engines often benefit significantly from UCLs because they help bridge the gap between older engine designs and modern fuel characteristics.

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Product Comparison and Analysis

Let's examine the top UCLs on the market, comparing their key features and benefits based on my technical evaluation. We'll be comparing AMSOIL Upper Cylinder Lubricant, Lucas UCL, Sea Foam Motor Treatment, Sea Foam Fuel Injector Cleaner, Klotz UCL, and Hot Shot's Secret LX4 Lubricity Extreme.

Pricing Breakdown

First up, let's breakdown the cost of each fuel additive and see how they stack up with one another.

Upper Cylinder Lubricant Price Comparison

Brand	Cost/oz
Brand	Klotz UCL	Sea Foam Motor Treatment	AMSOIL UCL (PC Price)	Hot Shot's Secret	Lucas UCL	AMSOIL UCL (Regular)	Sea Foam Injector Cleaner
Cost/oz
Klotz UCL
Sea Foam Motor Treatment
AMSOIL UCL (PC Price)
Hot Shot's Secret
Lucas UCL
AMSOIL UCL (Regular)
Sea Foam Injector Cleaner

We've broken down the cost of each product and compared them so you know which is cheapest and most expensive. According to the table above, the Klotz Uplon Upper Cylinder Cleaner comes in as the cheapest at around $0.69 per fluid ounce, while the Sea Foam Fuel Injector Cleaner is the most expensive at $1.24 per ounce. Notice for AMSOIL Preferred Customers (membership costs $10 per 6 months), the AMSOIL UCL is significantly cheaper than Hot Shot's Secret and just slightly more expensive than Sea Foam Motor Treatment.

Technical Specs Analysis

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Performance Testing

There haven't too many performance tests done comparing popular upper cylinder lubricants from different brands, but, AMSOIL did publish an independent test comparing their UCL with Sea Foam Motor Treatment and Lucas Upper Cylinder Lubricant

Modified ASTM D6079

The ASTM D6079 testing method evaluates the lubricity of diesel fuels by using a High Frequency Reciprocating Rig (HFFR). Essentially, a metal ball reciprocates along a metal disc for 75 minutes, using fuel as the lubricant, and then a wear scar is measured to determine the fuel's lubricity (smaller wear scar = better lubricity). This test was slightly modified using gasoline instead of diesel.

Test Results

• The base fuel (E10 - regular unleaded ethanol blend) produced a wear scar of 807 μm.
• Sea Foam Motor Treatment showed the least amount of improvement, producing a wear scar of 803 μm.
• Lucas Upper Cylinder Lube was a bit better at 786 μm.
• AMSOIL delivered 18% more lubricity than Lucas and 20% more lubricity than Sea Foam with a wear scar of 640 μm.

Based on independent testing of AMSOIL Upper Cylinder Lubricant, Lucas Upper Cylinder Lubricant and Sea Foam Motor Treatment obtained on 02/13/2019 using the ASTM D6079 modified for use with gasoline.

Overall, AMSOIL UCL increased the gasoline fuel lubricity by 21%.

Diesel Fuel Additive Testing

Hot Shot's Secret has published some testing data for their LX4 Lubricity Extreme product using diesel fuel. According to their Certificate of Analysis from 2019, the baseline diesel fuel created a wear scar of 363 μm, while the sample with LX4 added dropped the wear scar down to 236.5 μm, resulting in a lubricity increase of 34.8%, which is really good. AMSOIL's UCL is explicitly for gasoline engines, their Diesel Injector Clean is best for improving lubricity in diesel applications.

AMSOIL performed multiple ASTM D6079 tests using diesel fuel samples across several US states. On average, Diesel Injector Clean resulted in a 29.9% improvement in fuel lubricity, showing the best improvement in the state of Washington with a 38.9% reduction in the wear scar.

Common Questions Answered

Based on my engineering experience and extensive testing, here are answers to common questions about UCLs:

Is Upper Cylinder Lubricant Worth It?

Yes, especially in modern engines using ethanol-blended fuels. Significant fuel lubricity improvements and wear reduction in engines using quality UCLs has been verified through independent testing, particularly in direct-injection applications where fuel washing can be an issue.

What Makes AMSOIL Upper Cylinder Lubricant Different?

The synthetic chemistry used in AMSOIL's UCL provides superior protection in extreme temperatures and maintains its protective properties longer than conventional alternatives. This is particularly important in modern engines with higher operating temperatures and tighter tolerances.

When and Where to Add UCL?

Add it to your fuel tank before filling up. This ensures proper mixing. For best results, add it every time you fuel up to maintain consistent protection.

Can You Use Too Much Fuel Additive?

Yes. Always follow the recommended treating ratios. Over-treating can lead to deposit formation and potential sensor issues. It's very possible to over-treat your gas tank with more fuel additive than what is recommended which can cause additional problems.

Diesel vs. Gasoline Applications

UCLs can benefit both engine types, but diesel engines often see more dramatic improvements due to their higher compression ratios and the varying quality of diesel fuel. In my experience having driven primarily diesel trucks in cold Michigan climates, diesel engines showed particularly good response to UCL treatment, especially in cold weather operation.

My Professional Recommendations

After decades of engineering experience and extensive testing, I recommend AMSOIL Upper Cylinder Lubricant for gasoline applications and Diesel Injector Clean to improve the lubricity of diesel fuel. Here's why:

1. Superior Protection: The synthetic formulation provides better protection across a wider temperature range
2. Cleaning Properties: Helps keep injectors clean while lubricating
3. Compatibility: Works well with modern engine technology and sensors
4. Cost-Effective: The concentrated formula makes it economical per treatment

Remember, while UCLs are beneficial, they're part of a complete maintenance strategy. Regular oil changes, quality fuel, and proper maintenance intervals are equally important for engine longevity.

Best Practices for UCL Use

Based on my engineering experience, here are some key tips for getting the most benefit from UCLs:

1. Use consistently for best results
2. Add before fueling to ensure proper mixing
3. Follow recommended treatment ratios
4. Use in conjunction with quality fuel
5. Maintain regular maintenance intervals

Conclusion

Upper cylinder lubricants are a valuable tool in protecting modern engines, particularly with today's fuel formulations. While there are many options available, synthetic formulations like AMSOIL's Upper Cylinder Lubricant provides superior protection and value for most applications. As always, I'm available to answer any specific questions about your application or needs.

Sources

• AMSOIL Upper Cylinder Lube Data Sheet
• Klotz Uplon Data Sheet
• Sea Foam Motor Treatment Data Sheet
• Sea Foam Injector Clean Data Sheet
• Lucas Upper Cylinder Lubricant Data Sheet
• Hot Shot's Secret LX4 Lubricity Extreme Data Sheet
• Hot Shot's Secret LX4 ASTM D6079 Testing Results