Dex-Cool coolant flush:$110 to $200OAT orange, GM factory spec, 2026
Dex-Cool is the orange OAT (organic acid technology) coolant General Motors has installed at the factory in nearly every passenger vehicle since 1996. The 150,000-mile or 5-year interval is the longest in the mainstream US market. The historical sludge controversy has been studied and resolved; the modern formulation performs to its full interval in healthy systems.
Indy shop
$110 - $170
Full machine flush
Chain
$99 - $159
OAT-compatible exchange
GM dealer
$180 - $280
ACDelco genuine Dex-Cool
Spec card
Dex-Cool / OAT orangeVehicle mapping
Which GM vehicles run Dex-Cool
Chevrolet
Silverado, Tahoe, Suburban, Equinox, Traverse, Malibu, Camaro, Corvette, Trailblazer, Blazer, Trax
GMC
Sierra, Yukon, Yukon XL, Acadia, Terrain, Canyon
Cadillac
Escalade, XT5, XT6, CT4, CT5, CTS, ATS, Lyriq (separate EV coolant)
Buick
Enclave, Envision, Encore, LaCrosse, Regal
Ford (post-2018 only)
F-150 EcoBoost models, Mustang EcoBoost, Edge ST, Explorer ST
Chrysler / Dodge (some)
Specific FCA models share the 6277M-equivalent spec. Verify against owner's manual before assuming Dex-Cool compatibility.
The sludge story
What the Dex-Cool controversy was actually about
A class-action lawsuit filed against GM in the early 2000s alleged Dex-Cool caused premature intake-manifold gasket failures in 3.1L, 3.4L, and 3.8L V6 engines from the 1996 to 2004 model years. The story dominated automotive forums for a decade and still colors how some technicians talk about Dex-Cool today.
The actual mechanism, as documented in subsequent technical analysis, was more nuanced than "Dex-Cool destroys engines." The lower-silicate OAT formulation in Dex-Cool relies on a continuous, sealed coolant loop to maintain its inhibitor chemistry. When air leaks past a separate failing gasket (a known weakness in those particular V6 intake manifolds), the air contact accelerated the breakdown of Dex-Cool's additive package and caused a brown sludge to form. The sludge then made the underlying gasket leak worse. The root cause was the gasket, not the coolant. In a sealed system with healthy gaskets, the same Dex-Cool ran 150,000 miles without sludge.
GM settled the lawsuit in 2008 with reimbursements to affected owners but maintained that Dex-Cool itself was not defective. The formulation has been used continuously since, with no recurrence of widespread sludge issues. Modern GM cooling systems with improved gasket designs have not shown the original failure pattern.
The practical lesson today is that Dex-Cool needs a tightly sealed cooling system. A cap that leaks under pressure, a reservoir cracking at the neck, or a hose seep all reduce Dex-Cool's service life and can shorten the 150k interval. The annual cooling-system pressure test that most shops include with a flush is the right defensive maintenance.
Dex-Cool red flags to act on
- Coolant in reservoir has gone from orange to dark brown.
- Visible debris or sediment floating in the reservoir.
- Reservoir fluid level dropping between top-offs (air ingress likely).
- Cap pressure test failing at the spec rating.
- Temperature gauge climbing past normal in summer traffic.
Any of these means the system needs more than a flush. Pressure-test, find the leak, fix the leak, then flush.
DIY parts cost
If you flush Dex-Cool yourself
A DIY Dex-Cool drain-and-fill on a Silverado, Tahoe, or Equinox is a straightforward weekend job. The hardest part is bleeding the air after the refill. Most GM vehicles have a bleed screw on the thermostat housing that opens during the bleed cycle. Without it, air pockets can survive in the heater core and cause warm cabin air in winter.
Parts cost runs $40 to $90 for the coolant depending on vehicle capacity and brand choice. Tools needed: a drain pan that holds at least 4 gallons, a basic socket set for the radiator drain (the petcock on most GMs), a funnel with a hose to reach the radiator fill neck, and a clean rag. A no-spill funnel that screws onto the radiator neck makes bleeding easier and reduces overflow.
Total DIY savings versus a chain flush is $50 to $130 depending on vehicle size and the chain price in your metro. The savings argument is strongest on full-size trucks and SUVs where the shop charges more for the larger capacity.
DIY parts list
| Dex-Cool 50/50 ready-to-use, 1 gal | $14 - $22 |
| Dex-Cool concentrate, 1 gal | $20 - $30 |
| Distilled water, 1 gal (for concentrate) | $1 - $2 |
| Funnel with no-spill neck adapter | $15 - $30 |
| Drain pan (5+ gal) | $12 - $25 |
| Storage jug for old coolant | $3 - $8 |
Pricing from AutoZone, Advance, NAPA, and O'Reilly sampled May 2026. Drain pan and funnel are one-time purchases.
Common questions
Dex-Cool flush FAQ
How much does a Dex-Cool flush cost in 2026?
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A Dex-Cool coolant flush costs $110 to $200 at most independent and chain shops in 2026, with a GM dealer typically charging $180 to $280. The price is slightly above the universal-coolant baseline because Dex-Cool is an OAT (organic acid technology) formulation rather than the cheapest IAT formulation. A full-size truck or SUV with 4+ gallons of capacity sits at the top of the range.
What is Dex-Cool and what vehicles use it?
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Dex-Cool is the orange OAT (organic acid technology) coolant specified by General Motors for nearly all of its passenger vehicles since 1996. It is the factory fill in the Silverado, Tahoe, Suburban, Sierra, Yukon, Equinox, Traverse, Malibu, Camaro, Corvette, and most Buick and Cadillac models. Some non-GM vehicles also spec Dex-Cool, including certain post-2018 Ford F-150 and Mustang models.
How often should Dex-Cool be flushed?
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GM's factory recommendation for current Dex-Cool installations is 5 years or 150,000 miles, whichever comes first. The interval applies to a system that has only ever had Dex-Cool. If the system was ever mixed with green IAT or yellow HOAT, the interval shortens to 30,000 to 50,000 miles and a full machine flush is recommended at each service.
Did Dex-Cool really cause engine damage?
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The 2000-2008 lawsuits against GM centered on intake-manifold gasket failures in some 3.1L, 3.4L, and 3.8L V6 engines. Dex-Cool itself was not the root cause. The problem was the lower-silicate Dex-Cool formulation reacting with air ingress through a separate gasket leak path, creating sludge. In sealed cooling systems with no air ingress, Dex-Cool performs to its intended 150,000-mile interval without sludge issues.
Can I switch from Dex-Cool to a different coolant?
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Yes, but the switch requires a complete machine flush including the heater core to remove all traces of the old chemistry. The most common switch is to a universal long-life OAT coolant that meets the Dex-Cool specification. Switching to green IAT or yellow HOAT is not recommended as both are less suited to the modern aluminum-heavy GM cooling systems.
What does Dex-Cool actually cost per gallon?
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Pre-diluted Dex-Cool 50/50 ready-to-use sells for $14 to $22 per gallon at AutoZone, Advance, NAPA, O'Reilly, and Walmart. Concentrate runs $20 to $30 per gallon. GM ACDelco-branded Dex-Cool from the dealer is closer to $25 to $35 per gallon. A small sedan needs about 2 gallons of 50/50 ready-to-use. A full-size truck or SUV needs 4 to 5 gallons.
Is universal OAT the same as Dex-Cool?
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Most universal OAT coolants are formulated to meet the Dex-Cool specification (GM 6277M or GM 6038M depending on era). The Prestone Command, Peak Long Life, and Zerex Dex-Cool products all carry the Dex-Cool approval. Verify the product label specifically lists Dex-Cool compatibility before using it as a replacement in a GM vehicle.