About this item

• Product Overview

  Diesel Cold Flow is formulated for a broad range of diesel fuels, including biodiesel and #1 and #2 ultra-low-sulfur diesel (ULSD). Diesel Cold Flow delivers confidence in your diesel's performance. Its concentrated formula uses unique chemistry to target and eliminate specific performance issues, maximizing diesel power.

  Reduces Need for #1 Diesel Fuel
  Using #1 diesel fuel is one traditional solution to cold-weather diesel fuel problems. While #1 diesel fuel has an advantage in low-temperature operability, the energy content of #1 diesel fuel is about 95 percent that of #2 diesel fuel, resulting in reduced fuel economy and less horsepower, and it costs more at the pump. Diesel Cold Flow minimizes the need for blending standard #2 diesel fuel with #1 diesel fuel, helping to maintain fuel economy and keep engines functioning normally.

  Helps Prevent Gelling
  As the temperature drops, the wax naturally found in diesel fuel begins to crystallize. The point at which wax crystals form is known as the cloud point. These wax crystals eventually clog the fuel filter and starve the engine of fuel, preventing it from starting. While low-quality fuels may form wax crystals in temperatures as warm as 40°F (4°C), most fuels have a cloud point near 32°F (0°C). The point at which the crystals clog the fuel filter is known as the cold filter-plugging point (CFPP). Diesel Cold Flow lowers the CFPP by up to 40°F (22°C) in ULSD.

  Additional Benefits
  Diesel Cold Flow uses a wax anti-settling component not found in other market-leading products. Wax anti-settling additives effectively modify wax crystals, drastically reducing their size. They resist settling and can pass through the filter more effectively, extending operability to a lower temperature.

  Prevents Wax Settling
  Wax crystals can settle and clog fuel filters (see picture). AMSOIL Diesel Cold Flow is formulated with wax anti-settling additives that drastically reduce the size of wax crystals, preventing them from settling and allowing them to more effectively pass through the filter, improving low-temperature operability.

  • Lowers cold filter-plugging point (CFPP) by up to 40°F
  • Enhances engine reliability in cold temperatures
  • Fights gelling in cold weather
  • Improves low-temperature startability
  • Prevents wax settling during storage
  • Inhibits fuel-filter icing
  • Safe for use in all diesel fuels, including biodiesel
  • Reduces downtime and maintenance costs
  • Alcohol-free

  APPLICATIONS
  Diesel Cold Flow is specially formulated for improving the flow of diesel fuel, helping to maintain the integrity of fuel and prevent the clogging of filters and injectors. It is excellent for use with diesel fuels, heating oils and kerosene.

  RECOMMENDATIONS
  Add before filling tank. Diesel Cold Flow must be added at temperatures above the diesel fuel cloud point (the temperature at which wax begins to crystallize). It will not reverse gel or wax crystals once formed. Do not store at temperatures below 0°F (-18°C). Excellent for use with AMSOIL Cetane Boost and AMSOIL Diesel Injector Clean.

  AMSOIL PRODUCT WARRANTY
  AMSOIL products are backed by a Limited Liability Warranty. For complete information visit www.amsoil.com/warranty/.

• Technical Specifications
  Data Bulletin

  Data Bulletins

  Warranty

  WARRANTY

  SDS

  SDS

  
  
  
• Product Reviews
  4.9 star rating

  Based on 307 reviews

  Based on 307 reviews

  See all customer reviews

  Sort by

  Most Recent Most Helpful Highest Rating Lowest Rating Oldest

  • 5 star rating
    New to the product
    By  Joe,  a  Verified Buyer  from  Gardnerville NV  on  March 05, 2026

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    Just starting using Amsoil 4-1 Diesel fuel treatment based on social media recommendations. Have gone through 3 tanks, every other fill up, and seems my Cummings 6.7 gen-4 with 120k is running a little smoother. However no news is good news in this case.
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Works
    By  TODD,  a  Verified Buyer  on  March 02, 2026

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    Product works as should
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Winter use of 4 in 1
    By  JOE,  a  Verified Buyer  from  Up Nort  on  February 18, 2026

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    Great product! Noticed better cold starts, fuel economy, and power.
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    All in One!
    By  CCMDawg,  a  Verified Buyer  from  Arizona  on  February 12, 2026

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    This is a great all in one product. One bottle works for all my needs including the annual trip to Wyoming in freezing climate.
    Bottom Line

    Yes, I would recommend this to a friend.
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  • 5 star rating
    Low cost investment
    By  NICK,  a  Verified Buyer  from  Erin Ontario   on  February 05, 2026

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    My truck got some bad fuel (water) and my injectors suffered, I kept using this 4in1 to help lubricate the pump and injectors in hopes of extending their life, was constant injector performance faults. Took about 1 month of continuous use but the faults are gone. I also started to use this product on all my construction machines, especially like that it has the anti gel additive, it’s helped me a few times.
    Bottom Line

    Yes, I would recommend this to a friend.
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    YES (1) NO (0)
  • 5 star rating
    Works Great
    By  REX,  a  Verified Buyer  from  NE Montana  on  January 22, 2026

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    I have only used a single bottle so far. However, having said that it works. I live in a very cold climate and it is doing its job.
    Bottom Line

    Yes, I would recommend this to a friend.
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    YES (1) NO (0)
  • 5 star rating
    Great product
    By  QUENTIN,  a  Verified Buyer  from  Kansas  on  January 16, 2026

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    Great product I fill like my truck runs better on this and I don’t have to worry about the fuel gelling on me.
    Bottom Line

    Yes, I would recommend this to a friend.
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    YES (1) NO (0)
  • 5 star rating
    Maintains
    By  EDWARD,  a  Verified Buyer  from  Kennewick   on  January 16, 2026

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    Never have had any problems with injectors clogging up. Can rely on consistent power.
    Bottom Line

    Yes, I would recommend this to a friend.
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    YES (1) NO (0)
  • 4 star rating
    Worked at -20 F
    By  Gus,  a  Verified Buyer  from  Wisconsin  on  January 12, 2026

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    Four stars only because I wasn't able to rate it any lower than -20 degrees Fahrenheit. Diesel was unblended #2 with a sudden cold snap arriving and used the additive without starting or running issues on a ungaraged diesel over a three day period.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (1)
  • 5 star rating
    Cold starts
    By  DELBERT,  a  Verified Buyer  from  Kentucky   on  January 11, 2026

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    The cold starts fuel additive works well i use it in my 2021 gladiator, 2001 dually duramax and my farm tractor it helps all 3 of them in the cold weather i highly recommend this product.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)

• Highlights

  Combats fuel gelling in cold weather

  • Lowers cold filter-plugging point (CFPP) by up to 40°F (22°C)
  • Fights gelling in cold weather
  • Prevents wax settling during storage
  • Inhibits fuel-filter icing
  • Safe for use in all diesel fuels, including biodiesel
• Returns

  We offer easy returns for customers. If your product is unused and unopened, you may return it within 30 days for a full refund of the purchase price. View full AMSOIL Return Policy.

• Payments

  We accept Visa, Mastercard, American Express, Discover and PayPal, and provide secure checkout and encrypted payment processing.

• Product Overview

  Diesel Cold Flow is formulated for a broad range of diesel fuels, including biodiesel and #1 and #2 ultra-low-sulfur diesel (ULSD). Diesel Cold Flow delivers confidence in your diesel's performance. Its concentrated formula uses unique chemistry to target and eliminate specific performance issues, maximizing diesel power.

  Reduces Need for #1 Diesel Fuel
  Using #1 diesel fuel is one traditional solution to cold-weather diesel fuel problems. While #1 diesel fuel has an advantage in low-temperature operability, the energy content of #1 diesel fuel is about 95 percent that of #2 diesel fuel, resulting in reduced fuel economy and less horsepower, and it costs more at the pump. Diesel Cold Flow minimizes the need for blending standard #2 diesel fuel with #1 diesel fuel, helping to maintain fuel economy and keep engines functioning normally.

  Helps Prevent Gelling
  As the temperature drops, the wax naturally found in diesel fuel begins to crystallize. The point at which wax crystals form is known as the cloud point. These wax crystals eventually clog the fuel filter and starve the engine of fuel, preventing it from starting. While low-quality fuels may form wax crystals in temperatures as warm as 40°F (4°C), most fuels have a cloud point near 32°F (0°C). The point at which the crystals clog the fuel filter is known as the cold filter-plugging point (CFPP). Diesel Cold Flow lowers the CFPP by up to 40°F (22°C) in ULSD.

  Additional Benefits
  Diesel Cold Flow uses a wax anti-settling component not found in other market-leading products. Wax anti-settling additives effectively modify wax crystals, drastically reducing their size. They resist settling and can pass through the filter more effectively, extending operability to a lower temperature.

  Prevents Wax Settling
  Wax crystals can settle and clog fuel filters (see picture). AMSOIL Diesel Cold Flow is formulated with wax anti-settling additives that drastically reduce the size of wax crystals, preventing them from settling and allowing them to more effectively pass through the filter, improving low-temperature operability.

  • Lowers cold filter-plugging point (CFPP) by up to 40°F
  • Enhances engine reliability in cold temperatures
  • Fights gelling in cold weather
  • Improves low-temperature startability
  • Prevents wax settling during storage
  • Inhibits fuel-filter icing
  • Safe for use in all diesel fuels, including biodiesel
  • Reduces downtime and maintenance costs
  • Alcohol-free

  APPLICATIONS
  Diesel Cold Flow is specially formulated for improving the flow of diesel fuel, helping to maintain the integrity of fuel and prevent the clogging of filters and injectors. It is excellent for use with diesel fuels, heating oils and kerosene.

  RECOMMENDATIONS
  Add before filling tank. Diesel Cold Flow must be added at temperatures above the diesel fuel cloud point (the temperature at which wax begins to crystallize). It will not reverse gel or wax crystals once formed. Do not store at temperatures below 0°F (-18°C). Excellent for use with AMSOIL Cetane Boost and AMSOIL Diesel Injector Clean.

  AMSOIL PRODUCT WARRANTY
  AMSOIL products are backed by a Limited Liability Warranty. For complete information visit www.amsoil.com/warranty/.

• Technical Specifications
  Data Bulletin

  Data Bulletins

  Warranty

  WARRANTY

  SDS

  SDS

  
  
  
• Product Reviews
  4.9 star rating

  Based on 307 reviews

  Based on 307 reviews

  See all customer reviews

  Sort by

  Most Recent Most Helpful Highest Rating Lowest Rating Oldest

  • 5 star rating
    New to the product
    By  Joe,  a  Verified Buyer  from  Gardnerville NV  on  March 05, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Just starting using Amsoil 4-1 Diesel fuel treatment based on social media recommendations. Have gone through 3 tanks, every other fill up, and seems my Cummings 6.7 gen-4 with 120k is running a little smoother. However no news is good news in this case.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (1)
  • 5 star rating
    Works
    By  TODD,  a  Verified Buyer  on  March 02, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Product works as should
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (0) NO (1)
  • 5 star rating
    Winter use of 4 in 1
    By  JOE,  a  Verified Buyer  from  Up Nort  on  February 18, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Great product! Noticed better cold starts, fuel economy, and power.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)
  • 5 star rating
    All in One!
    By  CCMDawg,  a  Verified Buyer  from  Arizona  on  February 12, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    This is a great all in one product. One bottle works for all my needs including the annual trip to Wyoming in freezing climate.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (2) NO (0)
  • 5 star rating
    Low cost investment
    By  NICK,  a  Verified Buyer  from  Erin Ontario   on  February 05, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    My truck got some bad fuel (water) and my injectors suffered, I kept using this 4in1 to help lubricate the pump and injectors in hopes of extending their life, was constant injector performance faults. Took about 1 month of continuous use but the faults are gone. I also started to use this product on all my construction machines, especially like that it has the anti gel additive, it’s helped me a few times.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)
  • 5 star rating
    Works Great
    By  REX,  a  Verified Buyer  from  NE Montana  on  January 22, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    I have only used a single bottle so far. However, having said that it works. I live in a very cold climate and it is doing its job.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)
  • 5 star rating
    Great product
    By  QUENTIN,  a  Verified Buyer  from  Kansas  on  January 16, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Great product I fill like my truck runs better on this and I don’t have to worry about the fuel gelling on me.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)
  • 5 star rating
    Maintains
    By  EDWARD,  a  Verified Buyer  from  Kennewick   on  January 16, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Never have had any problems with injectors clogging up. Can rely on consistent power.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)
  • 4 star rating
    Worked at -20 F
    By  Gus,  a  Verified Buyer  from  Wisconsin  on  January 12, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    Four stars only because I wasn't able to rate it any lower than -20 degrees Fahrenheit. Diesel was unblended #2 with a sudden cold snap arriving and used the additive without starting or running issues on a ungaraged diesel over a three day period.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (1)
  • 5 star rating
    Cold starts
    By  DELBERT,  a  Verified Buyer  from  Kentucky   on  January 11, 2026

    Open report issue form

    Describe the issue

    Failed to verify captcha

    Cancel Submit
    The cold starts fuel additive works well i use it in my 2021 gladiator, 2001 dually duramax and my farm tractor it helps all 3 of them in the cold weather i highly recommend this product.
    Bottom Line

    Yes, I would recommend this to a friend.
    Was this review helpful?

    YES (1) NO (0)