2019 Chevrolet Silverado 1500 Coolant Flush — 5.3L and 6.2L V8, Dex-Cool

I did the coolant service on my 2019 Silverado 5.3L at 150,000 miles — GM says 150k is the first change interval with Dex-Cool, and the fluid was still pink-orange but showing depleted freeze protection on my tester. This is a simple job that takes about an hour. The only thing you have to get right is the coolant type. Here's exactly how I do it.

Engine Compatibility

Engine	Coolant
2.7L Turbo 4-cylinder	Dex-Cool orange OAT
4.3L V6 EcoTec3	Dex-Cool orange OAT
5.3L EcoTec3 V8 (L82/L84)	Dex-Cool orange OAT
6.2L EcoTec3 V8 (L87)	Dex-Cool orange OAT
3.0L Duramax diesel	Dex-Cool orange OAT

All 2019 Silverado 1500 engines use the same GM Dex-Cool orange OAT coolant.

Coolant Specs

Item	Spec
Coolant type	GM Dex-Cool Extended Life Coolant (orange)
GM part number	88861011 (gallon)
Aftermarket equivalents	ACDelco 10-1035, Prestone Dex-Cool
Mixing ratio	50/50 Dex-Cool/distilled water
System capacity — 5.3L V8	~14.7 qt (13.9L)
System capacity — 6.2L V8	~15.0 qt (14.2L)
First change interval	150,000 miles or 5 years
Subsequent interval	Every 50,000 miles or 5 years
Petcock	Hand-tight only (plastic)

Tools & Materials

• GM Dex-Cool orange coolant 50/50 premix (2 gallons)
• Drain pan (4+ quarts)
• Flathead screwdriver or pliers (for petcock)
• Funnel
• Coolant tester (optional)
• Shop rags

Step-by-Step

1. Cool Down the Engine

Full cold engine only. Wait 2+ hours minimum.

2. Remove the Surge Tank Cap

The 2019 Silverado uses a pressurized surge tank on the driver's side of the engine bay. Remove cap pressing and turning counterclockwise. Small hiss from residual pressure is normal.

3. Open the Drain Petcock

Radiator drain petcock is at the bottom driver's side corner of the radiator. Turn counterclockwise approximately 1/4 to 1/2 turn. Drain fully — 10–15 minutes.

You'll recover approximately 6–8 quarts from a gravity drain on the 5.3L.

4. Flush Pass with Distilled Water (Optional)

At 150k-mile service, a dilution flush pass is worth doing:

1. Close petcock hand-tight
2. Add 3–4 quarts of distilled water
3. Replace cap, start engine, run to operating temperature
4. Cool completely, drain again
5. Repeat if drained water is still deeply orange-brown

For routine 50k-mile interval with clean coolant, skip.

5. Close the Drain

Close petcock hand-tight only — no wrench on plastic. If leaking after hand-tightening, replace petcock O-ring.

6. Fill with Dex-Cool

Pour GM Dex-Cool 50/50 orange slowly into surge tank opening. Fill toward MAX cold line.

• 5.3L V8: Add approximately 7–8 quarts after single gravity drain
• 6.2L V8: Add approximately 7–9 quarts

7. Air Bleed the System

1. Fill to MAX cold line on surge tank
2. Leave cap off (or loosely on)
3. Start engine
4. Turn heater to maximum heat, fan on high
5. Let idle until thermostat opens — temp gauge rises to normal
6. Watch surge tank level — add coolant as air purges
7. Once upper radiator hose gets hot, level stabilizes
8. Replace surge tank cap
9. Check level after first cool-down

8. Check for Leaks

With engine at operating temp, check petcock and any hose connections for drips.

9. Test Drive

Drive 10–15 minutes. Temperature gauge should hold steady at normal operating position.

Common Mistakes

1. Mixing Dex-Cool with green conventional coolant. Adding green coolant to top off a Dex-Cool system creates silica gel deposits throughout cooling passages and the heater core. A clogged heater core costs $400–$800 to replace. Use orange Dex-Cool only.

2. Cracking the plastic petcock. Hand-tight only. Overtightening cracks the petcock and can crack the lower radiator tank. If it leaks, replace the petcock — don't add torque.

3. Ignoring the 5.3L AFM lifter connection. The 5.3L L82/L84 EcoTec3 with Active Fuel Management has a history of lifter failure. Overheating from coolant neglect accelerates conditions that cause premature lifter wear. Keep the cooling system fresh on these trucks.

4. Not refilling the overflow reservoir properly. Fill surge tank to MAX when cold. Below MIN after first heat cycle = add coolant before next drive.

Dex-Cool History Note

Dex-Cool developed a bad reputation in early-2000s GM vehicles. The modern Dex-Cool Extended Life formulation in 2019 Silverados is significantly improved. Sticking to the 5-year / 50k-mile refresh interval prevents the conditions that caused the original sludge issues.

Cost Comparison

	DIY	Chevy Dealer / Shop
Dex-Cool 50/50 (2 gallons)	$35–$50	—
Labor	$0	$150–$250
Total	$35–$50	$185–$300

Saving $135–$250 for about an hour of work.

For more Silverado maintenance, see the 2019 GMC Sierra 1500 oil change guide — same 5.3L EcoTec3 engine. Browse all 28+ DIY procedures at OwnerDrop.

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