The Bosch CP4.2 high-pressure fuel pump in the 6.7 Powerstroke has a well-earned reputation for self-destructing, and the root cause is no mystery. That pump was designed in Europe for fuel with far better lubricity than the ultra-low-sulfur diesel sold across the United States. When the CP4 runs dry, its internal roller and cam wear metal, send shrapnel downstream, and can take out injectors and the entire fuel system in one event. A quality fuel additive is the single most cost-effective insurance policy you can give that pump.
We focused on what actually matters for CP4 survival: measured lubricity improvement, cetane boost, water dispersal, and detergency that keeps injectors clean. Every product below is a real diesel additive that 6.7 Powerstroke owners run regularly. We ranked them by how well they protect the high-pressure pump first, with cold-weather and cleaning performance factored in. No filler, no spec-sheet parroting, just what we would put in our own tanks before a long tow.
| Photo | Product | Score | Buy |
|---|---|---|---|
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Hot Shot's Secret Diesel Extreme Best Overall for CP4 Protection Lubricity + cetane + detergent + water control, treats up to 400 gallons per quart |
9.5 | 🛒 Check Price |
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Archoil AR6200 Fuel Treatment Best Lubricity Boost Concentrated lubricity and combustion additive, 16 oz treats up to 320 gallons |
9.3 | 🛒 Check Price |
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Stanadyne Performance Formula Best All-Season Balance All-in-one detergent, lubricity, cetane, and water demulsifier formula |
9.1 | 🛒 Check Price |
 |
Opti-Lube XPD All Season Best Lubricity Test Performer All-season lubricity additive with cetane and detergent, 1 oz treats 5 gallons summer dose |
8.9 | 🛒 Check Price |
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Power Service Diesel Kleen +Cetane Boost Best Value Maintenance Cetane boost plus detergent and added lubricity, gray bottle warm-weather formula |
8.6 | 🛒 Check Price |
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Power Service Diesel Fuel Supplement +Cetane Boost Best for Cold Weather Anti-gel cold-flow improver with cetane and lubricity, white bottle winter formula |
8.4 | 🛒 Check Price |
 |
Lucas Oil Upper Cylinder Lubricant & Injector Cleaner Best Budget Lubricity Add-On Fuel-soluble upper cylinder lubricant and injector cleaner, treats both diesel and gas |
8.0 | 🛒 Check Price |
1. Hot Shot's Secret Diesel Extreme: Best Overall for CP4 Protection
Hot Shot’s Secret Diesel Extreme earns the top spot because it attacks every weakness that kills a CP4. The Bosch pump fails when fuel lubricity is too low, and this additive is built around a heavy lubricity package combined with a meaningful cetane bump and a detergent system that scrubs internal diesel injector deposits. For a 6.7 Powerstroke owner, that means you are not just protecting the high-pressure pump, you are also keeping the eight injectors downstream spraying correctly, which is exactly the chain reaction you want to prevent. Running it as a regular maintenance dose with a periodic full-strength clean gives the most complete coverage we found.
The honest weakness is dosing discipline. The product shines when you follow the heavier clean-up ratio, and that uses the bottle up quicker than a simple top-off additive, so the per-tank value drops if you treat aggressively every fill. It also will not undo mechanical damage that has already started, so this is prevention, not a rescue. Add it from the day the truck is healthy and the CP4 has a real fighting chance.
- Combines cetane boost, lubricity improver, and injector detergent in one bottle
- Designed as a periodic clean-up treatment plus ongoing protection
- Disperses water and removes existing internal diesel injector deposits
Pros: Strong lubricity gains that directly target the CP4 dry-running failure mode; Aggressive detergent package restores injector spray pattern; Trusted name among Powerstroke and Cummins owners
Cons: Best results come from the more frequent full-strength clean-up dose, which uses product faster; Bottle dosing for partial tanks takes a little math
2. Archoil AR6200 Fuel Treatment: Best Lubricity Boost
Archoil AR6200 has become almost a default recommendation in CP4 circles, and for good reason. Its entire design philosophy is built around lubricity and clean combustion, which is precisely the protection a 6.7 Powerstroke high-pressure pump needs most. The formula is concentrated, so a modest pour treats a full tank, and owners consistently report smoother idle and quieter injectors after a few tanks. If your single biggest fear is the CP4 grinding itself apart from dry fuel, this is among the most focused tools for that exact job.
Where it gives ground to our top pick is breadth. AR6200 is not a strong winter additive, so it will not protect you from gelling in deep cold the way a dedicated anti-gel blend does, and its cetane contribution is modest. For year-round CP4 insurance in a moderate climate it is excellent, but Northern owners will still want a separate anti-gel in the coldest months rather than leaning on this alone.
- Heavy emphasis on lubricity to protect the high-pressure pump and injectors
- Improves combustion efficiency and reduces injector deposits
- Highly concentrated, so a small dose covers a full tank
Pros: One of the strongest lubricity reputations in the diesel community; Concentrated formula stretches a long way per bottle; Popular specifically among CP4-equipped truck owners
Cons: Light cetane and cold-flow performance compared to dedicated winter blends; Premium positioning means you pay for the concentration
3. Stanadyne Performance Formula: Best All-Season Balance
Stanadyne carries unique credibility because the company designs and builds diesel fuel-injection equipment, so its Performance Formula is written by people who understand what a high-pressure pump tolerates. For a 6.7 Powerstroke, that translates to a balanced additive that lifts lubricity to protect the CP4, adds cetane for smoother starts, runs a detergent to keep injectors clean, and demulsifies water so your separator can do its job. It is the kind of all-rounder you can run every tank without overthinking it.
The trade-off is that being balanced means it does not top any single chart. Owners chasing maximum lubricity numbers will find more focused products, and the standard Performance Formula is not a deep-winter anti-gel, so cold-climate drivers need to switch to the all-weather variant when temperatures drop. As a do-everything maintenance additive for the average tower, though, it is hard to fault.
- Made by a fuel-system manufacturer that builds injection components
- Balanced blend of lubricity, cetane, and detergency for everyday use
- Demulsifies water so the filter can separate and drain it
Pros: Engineered by a company that actually makes diesel injection hardware; Well-rounded protection without needing multiple bottles; Reliable year-round maintenance dose
Cons: Not the absolute strongest in any single category; Standard formula is not an anti-gel, so winters need the all-weather version
4. Opti-Lube XPD All Season: Best Lubricity Test Performer
Opti-Lube XPD is famous for one thing above all: it repeatedly posts some of the best results in independent diesel lubricity bench tests, the same tests that measure how well an additive reduces wear scar in the fuel. Since CP4 failure is fundamentally a lubricity and wear problem, that test pedigree matters enormously here. The All Season blend also folds in cetane and detergent, so a 6.7 Powerstroke gets pump protection, cleaner injectors, and slightly better combustion from a single jug, all at a treat ratio that lasts.
The catch is in the name, all season, not all winter. Its cold-flow improvement is mild, so owners in genuinely brutal cold should pair it with a dedicated anti-gel rather than trusting XPD to prevent gelling on its own. The heavy dye is also cosmetic but worth knowing, since it can tint a clear filter bowl. For raw pump-saving lubricity, few additives match it.
- Consistently ranks at the top of independent diesel lubricity testing
- All-season blend with mild cold-flow improvement
- Includes detergent and cetane alongside the lubricity package
Pros: Outstanding measured lubricity, which is the core CP4 concern; All-season formula works across most of the year; Generous treat ratio keeps a jug going a long time
Cons: Mild winter cold-flow is not enough for the harshest climates; Strong dye can tint a light-colored fuel filter housing
5. Power Service Diesel Kleen +Cetane Boost: Best Value Maintenance
Power Service Diesel Kleen in the gray bottle is the additive you can buy at virtually any parts store, farm supply, or big-box automotive aisle, which makes it the practical backbone of a lot of 6.7 Powerstroke maintenance routines. It delivers a genuine cetane boost for smoother, quieter running, a strong detergent to keep injectors clean, and added lubricity to help protect the high-pressure pump. For an owner who just wants reliable, repeatable protection on every fill without ordering specialty product online, this is a sensible default.
Its limitation for this specific application is that the lubricity, while real, is not at the top tier where the dedicated CP4-focused additives live. If your truck sees hard towing and you want the absolute most wear protection, you may run a heavier lubricity additive alongside it. The gray bottle is also the warm-weather formula, so when winter hits you switch to the white anti-gel version rather than relying on this one.
- Widely available cetane and detergent additive for everyday use
- Adds lubricity protection on top of the cleaning package
- Easy treat ratio and stocked at most parts and farm stores
Pros: Easy to find anywhere, so you are never stuck without it; Solid cetane and detergent performance for regular driving; Strong everyday value for high-mileage owners
Cons: Lubricity is good but not class-leading for CP4 worst-case protection; Gray bottle is the warm-weather formula, not an anti-gel
6. Power Service Diesel Fuel Supplement +Cetane Boost: Best for Cold Weather
The white-bottle Power Service Diesel Fuel Supplement is the cold-weather counterpart to Diesel Kleen, and it earns its place because a gelled fuel system is its own kind of emergency for a 6.7 Powerstroke. It lowers the cold filter plugging point, prevents wax from clogging the filter, and in a pinch can reliquefy fuel that has already started to gel. Importantly for CP4 owners, it still carries a lubricity and cetane package, so you are not sacrificing pump protection just to get through winter.
The honest framing is that this is a seasonal tool, not a year-round CP4 additive. In summer it offers no benefit over the warm-weather options and the anti-gel chemistry is simply wasted. Treat it as the half of your additive routine that comes out when temperatures fall, paired with a lubricity-focused product the rest of the year, and it does exactly what a Northern diesel owner needs.
- Prevents fuel gelling and lowers the cold filter plugging point
- Adds cetane and lubricity along with anti-gel protection
- Reliquefies gelled fuel and de-ices frozen filters in emergencies
Pros: Genuine deep-winter gel protection for Northern owners; Still contributes lubricity to help protect the CP4; Widely stocked the moment cold weather arrives
Cons: Overkill and unnecessary in warm months; Lubricity is secondary to its anti-gel mission
7. Lucas Oil Upper Cylinder Lubricant & Injector Cleaner: Best Budget Lubricity Add-On
Lucas Upper Cylinder Lubricant is the simplest, most accessible way to put extra lubricity back into the dry diesel that threatens a CP4. It is a fuel-soluble lubricant that coats the injection system and upper cylinder area, and for a 6.7 Powerstroke owner the relevant benefit is that lubricity directly counters the exact failure mode the CP4 is prone to. It pours in easily, is forgiving on dosing, and is a very budget-friendly ways to make sure your fuel is never running bone dry through the pump.
What keeps it at the bottom of the ranking is focus. It is a lubricant first and not much else, so there is no cetane boost, no anti-gel, and only a light cleaning function. It works best as a supplement to a more complete additive rather than as your only line of defense. If you want a cheap lubricity insurance pour to run alongside a cetane or detergent product, though, it does that one job honestly and well.
- Adds upper cylinder and injection lubrication to dry pump fuel
- Helps clean and lubricate injectors during normal driving
- Simple pour-in treatment with a flexible treat ratio
Pros: Inexpensive way to add lubricity to every tank; Easy to find and widely available; Doubles as an injector lubricant and mild cleaner
Cons: No cetane boost or anti-gel function; Less targeted than dedicated CP4 lubricity formulas
Frequently Asked Questions
Why does the 6.7 Powerstroke CP4 pump need a fuel additive in the first place?
The Bosch CP4.2 pump was engineered for European diesel that has higher lubricity than the ultra-low-sulfur diesel sold in the United States. The pump relies on the fuel itself to lubricate its internal roller and cam, and when that fuel is too dry, those parts wear, generate metal debris, and can grenade the entire fuel system. A lubricity-focused additive raises the fuel’s wear-protection back to a level the pump was designed around, which is the most direct way to reduce the risk of a catastrophic CP4 failure.
What is the single most important property to look for in a CP4 additive?
Lubricity, measured as a reduction in wear scar in standardized fuel testing. Because CP4 failure is fundamentally a wear and friction problem, the additive’s ability to lubricate the pump’s internal contact surfaces matters more than anything else for protecting that specific component. Cetane boost, detergency, and water control are all valuable, but they are secondary to lubricity when your goal is keeping the high-pressure pump alive. Products that publish strong independent lubricity results are the ones to prioritize for this truck.
Can a fuel additive fix a CP4 pump that is already failing or making noise?
No. Additives are preventive, not restorative. Once the CP4 roller and cam have started to wear and shed metal, that damage is mechanical and permanent, and continuing to drive risks sending debris through the injectors and the whole fuel system. If you suspect your pump is already failing, stop driving and have the fuel system inspected rather than hoping an additive will reverse it. Start using a lubricity additive when the truck is healthy so the pump never reaches that point.
Should I run a different additive in winter for my 6.7 Powerstroke?
In cold climates, yes. Most lubricity-focused CP4 additives offer little or no anti-gel protection, so when temperatures drop you should add a dedicated cold-flow improver or switch to a winter-formulated blend that lowers the cold filter plugging point and prevents fuel from gelling. A common approach is to run a lubricity additive year-round for pump protection and add an anti-gel product on top of it during the coldest months, giving you both wear protection and gel prevention at the same time.
How often should I add fuel additive to protect the CP4?
For ongoing pump protection, most owners treat every fill-up at the maintenance dose so the fuel always carries adequate lubricity through the CP4. Some products also have a heavier clean-up dose meant to be run periodically, for example once every several thousand miles, to scrub injector deposits. Follow the bottle’s treat ratio carefully, since overdosing wastes product and underdosing leaves the pump exposed. Consistency matters more than concentration, so a steady per-tank routine beats occasional heavy doses.
Our Verdict
For protecting the 6.7 Powerstroke CP4, our top pick is Hot Shot’s Secret Diesel Extreme because it pairs strong lubricity with a serious detergent and cetane package, covering the pump and the injectors downstream in one bottle. Our runner up is Archoil AR6200, which delivers some of the most focused lubricity protection in the diesel community for owners whose single priority is keeping that high-pressure pump alive. Whichever you choose, run a lubricity additive consistently, add a dedicated anti-gel in deep winter, and treat the bottle as cheap insurance against a very expensive CP4 failure.
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