Duramax Engine Cooling Systems: Keeping Your Diesel Running Smoothly
TL;DR
- Duramax cooling systems use radiators, water pumps (electric in newer LM2 models), thermostats (190-220°F), and 50/50 OAT coolant to manage combustion heat under heavy loads
- Common failures include clogged radiators, degraded coolant, stuck thermostats, and LML-specific EGR cooler clogs — all causing overheating during towing[1][2]
- Flush coolant every 5 years/150,000 miles with Dex-Cool or Mobil Delvac OAT (rated 600,000 miles); always use distilled water in 50/50 mix
- Proven upgrades: Mishimoto intercooler (101% larger core for LML), high-capacity radiators, low-temp thermostats, and electric fan conversions deliver 20-30% better heat dissipation[1]
- 2019+ LM2 3.0L uses Active Thermal Management with dual electric pumps and rotary valves for precise cooling — producing 277 hp/460 lb-ft with superior efficiency
Your Duramax is built like a tank — until the cooling system falls behind. Here's the thing: that 400+ lb-ft of torque generates serious heat, especially when you're towing 15,000 pounds through the mountains or pushing your LML hard on the open road. The cooling system isn't just there to keep temperatures in check — it's what stands between reliable power and a blown head gasket. We're talking radiators, water pumps, thermostats, and coolant working together under pressure. Let's break down how to keep your Duramax running cool, what fails first, and which upgrades actually deliver results.
How Does the Duramax Cooling System Actually Work?
The Duramax cooling system uses a radiator, water pump, thermostat, fan clutch, and coolant to manage combustion heat. The water pump circulates coolant through the engine block, the thermostat regulates flow at 190-220°F, and the radiator dissipates heat to airflow — keeping your diesel at optimal operating temperature under heavy loads.
Your Duramax generates massive heat during combustion — that's physics. The cooling system's job is moving that heat away from critical engine components before damage occurs. Here's how each piece works together:
The radiator acts as the primary heat exchanger. Hot coolant flows through aluminum or copper fins while airflow (from driving or the fan) pulls heat away. Upgrade radiators increase fin density and core thickness for better dissipation.
The water pump circulates coolant constantly. Traditional belt-driven pumps work but create parasitic drag — robbing 3-5 horsepower. Newer LM2 3.0L models use electric pumps that eliminate this loss and provide precise flow control. You'll find the pump on the front of the engine, driven by the serpentine belt on older 6.6L variants.
The thermostat is your temperature gatekeeper. It stays closed during warmup, then opens at 190-220°F to allow coolant flow to the radiator. Low-temp aftermarket thermostats (like Mishimoto's) open earlier to reduce exhaust gas temperatures during towing.
The fan clutch engages when coolant temps rise, spinning the mechanical fan to pull air through the radiator. Electric fan conversions provide consistent airflow without relying on thermal engagement — a smart upgrade for heavy towing.
Coolant itself is a 50/50 mix of antifreeze and distilled water. GM Dex-Cool or Mobil Delvac OAT formulas prevent rust and scale while transferring heat efficiently. Modern OAT coolants last 150,000-600,000 miles depending on the formula.
Newer models like the 2019+ LM2 3.0L use Active Thermal Management (ATM) — electronically-controlled rotary valves, dual electric pumps, and multiple temperature sensors that precisely route coolant for faster warmup and targeted cooling. This tech delivers 277 hp and 460 lb-ft with better efficiency than mechanical systems.
What Are the Most Common Duramax Cooling System Problems?
Duramax cooling systems fail from clogged radiators, degraded coolant, failing water pumps, stuck thermostats, and air pockets. LML models (2011-2016) also suffer from dual EGR cooler clogs and rear oil cooler restrictions. These issues cause overheating, especially under heavy loads like towing or racing.[1][2]
Even the toughest cooling system has weak points. Here's what breaks first and why:
Overheating Under Load
Your temp gauge climbs past 220°F when towing or climbing grades. The usual suspects: clogged radiator fins from bugs and debris, failing water pump bearings that reduce flow, or a fan clutch that won't engage. Low coolant levels from slow leaks make this worse.
Coolant Leaks
Check your driveway. Green or orange puddles mean trouble. Cracked hoses, corroded radiator tanks, leaking water pump seals, or blown head gaskets all dump coolant. Head gasket failures on the LML are notorious — coolant mixes with oil or enters the combustion chamber, causing white smoke and catastrophic damage.[2]
Thermostat Failures
A stuck-open thermostat keeps your engine too cold — you'll see long warmup times, poor heater performance, and reduced fuel efficiency. A stuck-closed thermostat causes overheating fast. Replace with OEM or quality aftermarket units to avoid repeat failures.
Scale and Buildup
Running straight water or letting coolant degrade creates rust, scale, and sludge inside the block and radiator. This restricts flow and reduces heat transfer. You'll need a chemical flush to remove deposits — not just a drain-and-fill.
Air Pockets
Improper coolant filling leaves air trapped in the system, creating hot spots that cause localized overheating. If your coolant system holds more than 20 psi of pressure, you've got air or combustion gases leaking in — likely a head gasket issue.
LML-Specific Issues (2011-2016)
The LML generation added dual EGR coolers and a rear-mounted oil cooler integrated into the valve cover. These coolers clog with soot and restrict coolant flow, causing EGT spikes and overheating during towing. Aftermarket intercooler upgrades with 101% larger cores help offset this.[1][2]
| Problem | Symptoms | Common Cause |
|---|---|---|
| Overheating | Temp gauge >220°F, steam | Clogged radiator, low coolant, bad pump |
| Coolant Loss | Low reservoir, puddles | Cracked hoses, leaking gaskets |
| Poor Heat Transfer | Slow warmup, cold heater | Scale buildup, degraded coolant |
| EGT Spikes (LML) | High exhaust temps towing | Clogged EGR/oil coolers |
|
S&B Cold Air Intake | GM/Duramax LML 6.6L | 2011-2016 — Pair cooling upgrades with S&B's high-flow cold air intake to reduce intake air temperatures and maximize the benefits of your upgraded intercooler and radiator. |
How Do I Properly Maintain My Duramax Cooling System?
Maintain your Duramax cooling system by flushing coolant every 5 years or 150,000 miles with 50/50 Dex-Cool and distilled water, inspecting hoses and radiator fins for damage, testing the water pump and fan clutch for proper operation, and pressure testing the system under 20 psi to catch leaks early.
Cooling system maintenance isn't glamorous — but it prevents $5,000 head gasket jobs. Here's your maintenance checklist:
Flush and Replace Coolant on Schedule
Coolant degrades over time, losing its ability to transfer heat and prevent corrosion. Use only GM-approved Dex-Cool or equivalent OAT (Organic Acid Technology) coolant mixed 50/50 with distilled water — never tap water, which contains minerals that cause scale.
Proper fill procedure: Fill the surge tank while the engine is hot, run at 2,000-2,500 RPM until the thermostats open (radiator hose gets hot), then idle and add coolant in cycles. Pressure test — if it holds more than 20 psi, you've got leaks or combustion gases entering the system.
For fleet operators or DIYers with multiple trucks, automated flush machines like MotorVac complete a 4.5-gallon exchange in 5 minutes, ensuring proper air removal.
Inspect the Radiator and Hoses
Pop the hood monthly. Look for bent radiator fins, debris buildup between the radiator and condenser, cracked hoses, or loose clamps. Replace any hose showing cracks, bulges, or soft spots — these fail without warning. Clean the radiator fins with low-pressure water or compressed air.
Monitor Water Pump and Fan Clutch Performance
Listen for bearing noise from the water pump — a grinding or squealing sound means replacement time. Check for coolant weeping from the pump's weep hole. Test the fan clutch by spinning the fan when the engine is cold — it should spin freely but have slight resistance. When hot, it should lock up and provide strong airflow.
Test Your Thermostat
If your engine takes forever to warm up or overheats quickly, the thermostat is likely stuck. Replace it with a quality OEM unit or consider a low-temp aftermarket option if you tow heavy regularly — opening at 180°F instead of 195°F gives you more cooling headroom.
Pressure Test the System
Annual pressure testing catches small leaks before they become big problems. Rent or buy a cooling system pressure tester, pump it to 15 psi cold, and watch for pressure drop. Inspect all hoses, the radiator, water pump, and head gaskets for leaks.
Recommended Service Intervals
- Coolant flush: Every 5 years or 150,000 miles (OEM spec); premium OAT extends to 600,000 miles
- Hose inspection: Every oil change
- Radiator cleaning: Annually or as needed
- Water pump replacement: 100,000-150,000 miles preventatively
- Thermostat replacement: At first sign of issues or every 100,000 miles
Which Cooling System Upgrades Actually Work for Duramax Trucks?
Proven Duramax cooling upgrades include high-capacity aluminum radiators for extreme towing, Mishimoto intercooler packages with 101% larger cores for LML models,[3] low-temp thermostats that reduce EGTs, electric cooling fans for consistent airflow, and premium OAT coolant rated for 600,000 miles.[4] Match upgrades to your use case — towing demands different solutions than daily driving.
If you're pushing your Duramax beyond stock — heavy towing, performance tuning, or racing — cooling upgrades move from nice-to-have to necessary. Here's what actually delivers results:
Upgraded Radiators
Stock radiators handle daily driving fine. Tow 12,000+ pounds regularly or tune for extra horsepower, and you'll max out cooling capacity. High-capacity all-aluminum radiators increase fin density and core thickness, dissipating 20-30% more heat. Look for units with reinforced tanks and thicker tubes.
Mishimoto Intercooler Packages (2011-2016 LML)
The LML's intercooler is a known bottleneck. Mishimoto's direct-fit packages deliver 101% more core volume with 73% thicker bar-and-plate construction. The kit includes 3.5"/3.0" mandrel-bent aluminum pipes, silicone boots, and T-bolt clamps. Results: lower exhaust gas temperatures, reduced turbo stress, and better power consistency during towing — all without tuning. Available in silver or black with a lifetime warranty.[3]
Low-Temp Thermostats
Aftermarket thermostats from Mishimoto or HSP open at 180°F instead of the stock 195°F, giving you a 15-degree buffer before overheating. Pair with upgraded thermostat housings that include orange silicone hoses and drain valves for easy coolant changes. This setup is popular for 2020+ builds focused on clean engine bay aesthetics.
Electric Cooling Fans
Ditch the mechanical fan clutch for dual electric fans. You'll gain 3-5 horsepower by eliminating parasitic drag and get consistent cooling at idle or low speeds — critical for rock crawling or traffic. Electric setups use relays and temperature switches for automatic control.
High-Flow Water Pumps
Performance water pumps increase flow rate by 15-25% with larger impellers and optimized housings. Some versions eliminate the restrictive casting flash found in OEM pumps. Electric water pumps (like those in the LM2 3.0L) are the ultimate upgrade, offering variable flow controlled by the ECU.
Premium Coolant
Mobil Delvac Extended Life OAT coolant is rated for 600,000 miles or 8 years — 4x longer than standard Dex-Cool. It provides superior corrosion protection and heat transfer. For hoses, PPE silicone kits replace OEM rubber with reinforced silicone that withstands higher temperatures and pressures.
| Upgrade | Fitment | Primary Benefit | Price Range |
|---|---|---|---|
| High-Capacity Radiator | All Duramax | 20-30% more heat dissipation | $400-$800 |
| Mishimoto Intercooler | 2011-2016 LML | 101% larger core, lower EGTs | $600-$900 |
| Low-Temp Thermostat Kit | LML/LMM/L5P | 15°F lower operating temp | $100-$200 |
| Electric Fan Conversion | All Duramax | Consistent airflow, 3-5 hp gain | $300-$600 |
| Mobil Delvac Coolant | All Duramax | 600k mile service life | $30-$50/gal |
 GM/Chevy Duramax 2011-2016 LML" width="80" height="80" loading="lazy" style="border-radius:4px;object-fit:cover;display:block;" title="EGR Delete | GM/Chevy Duramax 2011-2016 LML">
|
EGR Delete | GM/Chevy Duramax 2011-2016 LML — Eliminate the dual EGR coolers that cause overheating and coolant flow restrictions on LML models — our complete delete kit addresses the root cause of many cooling issues. |
What Are the Warning Signs of Cooling System Failure?
Watch for these Duramax cooling system failure signs: engine temperature rising above 220°F especially under load, visible coolant leaks or low reservoir levels, white steam from the engine bay, sweet or burning smells near the radiator, poor heater performance, and milky oil indicating coolant contamination. Address issues immediately to prevent head gasket or engine damage.[2]
Cooling system failures don't happen instantly — your truck tells you something's wrong. Catch these signs early and you'll save thousands in repairs:
Rising Temperature Gauge
Your factory temp gauge should sit steady around 190-210°F. If it climbs above 220°F — especially while towing or climbing grades — your cooling system can't keep up. Don't ignore this. Pull over, let the engine cool, and diagnose the problem before continuing.
Visible Coolant Leaks
Orange or green puddles under your truck mean coolant is escaping. Check the ground after the truck sits overnight. Small leaks become big leaks fast — and running low on coolant causes overheating and head gasket damage. Track down the source: hoses, radiator, water pump weep hole, or head gaskets.
White Steam or Smoke
Steam pouring from under the hood means you're losing coolant fast — likely from a burst hose or boiling-over radiator. White smoke from the exhaust indicates coolant entering the combustion chamber through a blown head gasket. This is an emergency — shut down immediately.[2]
Sweet or Burning Smells
Coolant has a distinct sweet smell. If you smell it inside the cab or near the engine bay, coolant is leaking onto hot components. A burning smell suggests leaked coolant hitting the exhaust manifold or turbo. Both require immediate attention.
Poor Heater Performance
Your heater blows cold air even after the engine warms up. This indicates low coolant levels, air pockets in the system, or a clogged heater core. It's often the first subtle warning before bigger problems develop.
Milky or Contaminated Oil
Pull the dipstick. If your oil looks like chocolate milk, coolant is mixing with engine oil — a classic head gasket failure symptom. You'll also see white residue on the oil filler cap. Stop driving and get this diagnosed immediately. Running with contaminated oil destroys bearings.[2]
Excessive Pressure in Cooling System
Remove the radiator cap when cold. If coolant shoots out or the upper radiator hose feels rock-hard, you've got excessive pressure — likely from combustion gases entering the cooling system through a cracked head or blown gasket. This requires professional diagnosis with a block tester.
Rough Idle or Misfires
Coolant leaking into a cylinder causes misfires, rough idle, or hard starting. You might also notice reduced power. These symptoms combined with other cooling issues point to internal engine damage.[2]
The bottom line: your Duramax will tell you when the cooling system struggles. Listen to it. A $50 hose replacement today beats a $5,000 head gasket job tomorrow.
How Does Active Thermal Management Work in Newer Duramax Engines?
Active Thermal Management (ATM) in 2019+ Duramax LM2 3.0L engines uses electronically-controlled rotary valves, dual electric water pumps (one for the engine, one for the heater), and multiple temperature sensors to precisely route coolant. This system delivers faster warmup, targeted cooling, and improved efficiency compared to mechanical systems — helping produce 277 hp and 460 lb-ft.
The 2019+ LM2 3.0L Duramax brought diesel cooling into the modern era with Active Thermal Management — a smart system that makes cooling decisions on the fly instead of relying on simple thermostats.
How ATM Works
Traditional cooling systems are reactive — the thermostat opens at a set temperature and that's it. ATM is proactive. Electronically-controlled rotary valves adjust coolant flow paths based on real-time data from multiple temperature sensors throughout the engine. Two separate electric water pumps (one for the engine block, one for the heater core) provide variable flow rates controlled by the ECU.
During cold starts, ATM restricts coolant flow to help the engine reach operating temperature faster — improving fuel economy and reducing emissions during warmup. Once warm, the system precisely routes coolant to areas that need it most: the cylinder head during heavy loads, the oil cooler during high-speed driving, or the EGR system during emissions events.
Real-World Benefits
The payoff is efficiency. The LM2's 277 horsepower and 460 lb-ft of torque come from a smaller 3.0L displacement because ATM maintains optimal temperatures across all operating conditions. You get better fuel economy (23 city/33 highway in the Silverado), quicker warmup times in winter, and more consistent performance when towing.
Retrofit Potential for Older Duramax Models
Can you add ATM to your 6.6L LML or L5P? Not easily. The system requires extensive ECU integration, custom sensors, and wiring harnesses. But the concept proves electric water pumps and smart cooling control deliver real benefits — expect aftermarket solutions to emerge as the technology matures.
For now, older Duramax owners can achieve similar results by upgrading to high-flow electric water pumps with manual controllers, paired with quality thermostats and upgraded radiators. You won't get the ECU integration, but you'll gain the efficiency and power benefits of eliminating parasitic drag.
|
GM/Chevy Duramax 6.6 LML Full Delete Bundle | 2011-2016 — Our complete LML delete bundle removes emissions restrictions that increase heat load — reducing exhaust gas temperatures and stress on your cooling system during towing. |
What's the Correct Coolant Type and Mix Ratio for Duramax Engines?
Use 50/50 mix of GM Dex-Cool (orange) or equivalent OAT (Organic Acid Technology) coolant and distilled water in all Duramax engines. Never use straight water or tap water — minerals cause scale buildup that restricts flow and reduces heat transfer. Premium OAT coolants like Mobil Delvac last 150,000-600,000 miles with proper maintenance.
Coolant choice matters more than most diesel owners realize. The right mix protects your engine from corrosion, prevents freezing, and transfers heat efficiently. The wrong mix destroys everything.
Why 50/50 Mix Matters
Pure antifreeze freezes at a higher temperature than water and transfers heat poorly. Pure water boils at only 212°F and causes rust and scale. The 50/50 mix provides freeze protection to -34°F, boiling protection to 265°F (under pressure), and optimal heat transfer properties.
GM Dex-Cool: The OEM Standard
GM specifies Dex-Cool (orange-colored) for all Duramax engines. It's an OAT formula that lasts 5 years or 150,000 miles. Dex-Cool prevents corrosion of aluminum and cast iron components while maintaining stable pH levels. Never mix Dex-Cool with green conventional coolants — they're chemically incompatible and create sludge.
Premium Upgrade: Mobil Delvac OAT
Mobil Delvac Extended Life coolant takes OAT technology further — it's rated for 600,000 miles or 8 years. That's 4x longer than standard Dex-Cool. Fleet operators and high-mileage diesel owners use Delvac to reduce maintenance intervals and improve long-term engine protection. The cost difference is minimal when you consider the extended service life.
Why Distilled Water Only
Tap water contains calcium, magnesium, and other minerals that precipitate out at high temperatures, forming scale deposits inside the block, radiator, and water pump. These deposits restrict coolant flow and act as insulation, reducing heat transfer. Distilled water eliminates this problem. You can buy it at any grocery store for $1/gallon — cheap insurance.
Coolant Additives: Do They Work?
Some diesel owners add products like Water Wetter or Red Line coolant additives claiming improved heat transfer. The truth: if you're running proper 50/50 mix with quality coolant, additives provide minimal benefit. Save your money for proven upgrades like better radiators and intercoolers.
Mixing Different Brands
Stick with one coolant brand and type. If you must mix, ensure both are OAT-based (orange/pink color). Never mix OAT with IAT (green) or HOAT (gold) coolants. When in doubt, flush completely and start fresh with new coolant.
|
S&B Cold Air Intake | GM/Duramax L5P 6.6L | 2017-2023 — L5P owners benefit from S&B's improved airflow and filtration, helping maintain consistent intake temperatures that complement factory cooling system performance. |
"Your Duramax cooling system isn't just about preventing overheating — it's about maintaining precise temperature control under every condition, from cold starts to max-load towing. The difference between a stock system and a properly upgraded setup is the difference between limping up a grade at reduced power and maintaining full boost all the way to the summit. We've seen too many head gasket failures from neglected cooling systems that could've been prevented with a $50 coolant flush. Invest in cooling before you invest in horsepower — your engine will thank you at 300,000 miles."
— The Diesel Dudes Technical Team
Gear Up: What You'll Need
|
S&B Cold Air Intake | GM/Duramax LML 6.6L | 2011-2016 — High-flow intake reduces heat buildup and complements upgraded cooling systems |
|
EGR Delete | GM/Chevy Duramax 2011-2016 LML — Eliminates dual EGR coolers that restrict coolant flow and cause overheating |
|
GM/Chevy Duramax 6.6 LML Full Delete Bundle | 2011-2016 — Complete emissions delete reduces heat load and EGT spikes during towing |
|
5" Down Pipe-Back Full Exhaust Delete | GM/Chevy 6.6 Duramax 2017-2023 — Improved exhaust flow lowers backpressure and reduces underhood temperatures |
Frequently Asked Questions
What are the benefits of upgrading my Duramax cooling system?
Upgraded Duramax cooling systems prevent overheating during heavy towing, reduce exhaust gas temperatures, extend engine life, and support increased horsepower from tuning. High-capacity radiators dissipate 20-30% more heat, Mishimoto intercoolers add 101% core volume for LML models, and low-temp thermostats provide 15°F more cooling headroom. Electric fan conversions eliminate parasitic drag for 3-5 hp gains while improving airflow consistency. These upgrades are essential if you regularly tow over 10,000 pounds or run performance tunes.
How much does a Duramax cooling system upgrade cost?
Basic cooling maintenance (coolant flush, hoses, thermostat) runs $200-400. Significant upgrades range from $300 for electric fan conversions to $900 for complete Mishimoto intercooler packages. High-capacity radiators cost $400-800, low-temp thermostat kits run $100-200, and premium Mobil Delvac coolant is $30-50 per gallon. A full cooling system overhaul with upgraded radiator, intercooler, thermostat, and hoses typically costs $1,500-2,500 — far less than repairing overheating damage or blown head gaskets.
Is upgrading my Duramax cooling system worth it for daily driving?
For stock daily driving, OEM cooling systems work fine with proper maintenance. Upgrades become worth it when you regularly tow over 8,000 pounds, run in extreme climates (desert heat or mountain grades), or add performance tuning that increases horsepower beyond stock. If you're experiencing overheating, start with maintenance (flush coolant, clean radiator, replace thermostat) before investing in upgrades. However, preventative upgrades like premium coolant and improved hoses cost little and extend component life significantly.
What are the most common problems with Duramax cooling systems?
The most common Duramax cooling problems are clogged radiators from debris (causing overheating under load), degraded coolant creating scale buildup (restricting flow), failing water pump bearings (reducing circulation), stuck thermostats (over-cooling or overheating), and coolant leaks from cracked hoses or head gaskets. LML models (2011-2016) specifically suffer from clogged dual EGR coolers and restricted rear oil coolers. Warning signs include temperatures above 220°F, visible leaks, white steam, poor heater performance, and milky oil indicating head gasket failure.
How do I choose the right Duramax cooling upgrades for my truck?
Match upgrades to your use case: For heavy towing (10,000+ lbs), prioritize high-capacity radiators and low-temp thermostats. For LML models (2011-2016), Mishimoto intercooler packages address the known bottleneck with 101% larger cores. For performance tuning, combine upgraded radiator, electric fans, and high-flow water pumps. For daily drivers in hot climates, start with premium Mobil Delvac coolant and clean existing components. Always verify direct-fit compatibility for your specific year and model — LML, LMM, L5P, and LM2 have different mounting and plumbing.
Emissions Disclaimer: This article is intended for off-road and closed-course use only. Removing or modifying emissions control systems (DPF, EGR, DEF) on vehicles operated on public roads may violate federal and state regulations. The Diesel Dudes does not endorse illegal modifications.
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Key Facts:
- Duramax cooling systems use radiators, water pumps (electric in newer LM2 models), thermostats (190-220°F), and 50/50 OAT coolant to manage combustion heat under heavy loads
- Common failures include clogged radiators, degraded coolant, stuck thermostats, and LML-specific EGR cooler clogs — all causing overheating during towing[1][2]
- Flush coolant every 5 years/150,000 miles with Dex-Cool or Mobil Delvac OAT (rated 600,000 miles); always use distilled water in 50/50 mix
- Proven upgrades: Mishimoto intercooler (101% larger core for LML), high-capacity radiators, low-temp thermostats, and electric fan conversions deliver 20-30% better heat dissipation[1]
- 2019+ LM2 3.0L uses Active Thermal Management with dual electric pumps and rotary valves for precise cooling — producing 277 hp/460 lb-ft with superior efficiency
About The Diesel Dudes: The Diesel Dudes is the leading online retailer of diesel performance parts, delete kits, and tuning solutions for Cummins, Powerstroke, and Duramax trucks. Based in the USA, TDD provides expert technical advice and premium aftermarket parts.
Website: thedieseldudes.com
References
- SB 10088863 2280 – https://static.nhtsa.gov/odi/tsbs/2016/SB-10088863-2280.pdf
- Duramax Engine Cooling Systems: Keeping Your Diesel Running Smoothly – https://thedieseldudes.com/blogs/news/duramax-engine-cooling-systems-keeping-your-diesel-running-smoothly
- Mishimoto – LML Intercooler: 101% Larger Core Volume – https://mishimoto.com/
- Mobil Delvac Extended Life OAT Coolant – 600,000 Mile Service Life – https://www.mobil.com/en/lubricants/for-businesses/heavy-duty-lubricants/products/mobil-delvac-extended-life-coolant-antifreeze
About This Article
This article was written by The Diesel Dudes Technical Team — ASE-certified diesel technicians with decades of hands-on experience building, tuning, and maintaining diesel trucks. Our content is reviewed for technical accuracy and updated regularly. Published 2024-12-27.
Legal Notice: Removing or tampering with emissions equipment may violate the federal Clean Air Act and state emissions regulations. Penalties can include fines up to $5,000 for individuals. Check your local and state laws before modifying emissions equipment on any vehicle driven on public roads.
Disclosure: The Diesel Dudes sells some of the products mentioned in this article. Our recommendations are based on hands-on testing and customer feedback.