All WK gas engines use HOAT coolant (Mopar MS-9769 or equivalent Zerex G-05). The 4.7L V8 holds about 14.5 quarts; the 3.7L and 5.7L Hemi are in the same neighborhood. Mix 50/50 with distilled water — never tap.
The WK uses Hybrid Organic Additive Technology (HOAT) coolant, sold by Chrysler as MS-9769 — a 5-year, 100,000-mile formula. Zerex G-05 is the most common equivalent. Do not mix HOAT with green IAT or with Dex-Cool. Mixing turns the additives into a brown sludge that clogs heater cores and water pumps. If you pull the coolant and it's not gold or pink, flush twice and pay attention to the heater core afterward.
The 4.7L V8 holds 14.5 quarts when refilling with the reservoir at MAX. The 3.7L V6 is a touch less; the 5.7L Hemi is similar. Plan for two gallons of premix to do a proper flush — you will not get every drop of the old fluid out without pulling block plugs, and a single drain-and-fill leaves the heater core full of old fluid.
Best practice: drain the radiator at the lower petcock or hose, run the engine briefly with fresh distilled water in the system to push old fluid out of the heater core, drain again, then refill with the proper 50/50 mix. Burping the system matters — the WK has a bleeder near the thermostat housing, and you need to run the truck with the heater on full for 10–15 minutes after refill, watching the temp gauge, until the upper hose is hot and the fans cycle. Top off the reservoir, then check level after a few cool-warm cycles.
Old coolant is toxic to animals and has a sweet taste that draws dogs and wildlife. Catch every drop and dispose at an auto parts store that accepts used fluid. Never hose it into a driveway.
| Part | Vendor | Est. price |
|---|---|---|
| Mopar HOAT coolant (MS-9769) — 1 gallon premixed or concentrate | Mopar | ~$22 |
| Zerex G-05 HOAT coolant (equivalent), 1 gal | Valvoline / Zerex | ~$18 |
| Distilled water (1 gal — if mixing concentrate) | any grocery store | ~$2 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.