Used 6.4 HEMI (gas): what to check before you buy

1Before you go

Run the VIN and ask for the paperwork on the campaigns below: a done recall or program is a solved problem, an open one is a free repair the seller has not had done.

• Run the VIN

  It confirms the engine and lists the campaigns for that model year. Whether a recall is still open on this VIN: nhtsa.gov/recalls.

2Cold start and idle

Ask the seller not to start or warm the engine before you arrive. Most of these only show on a cold engine; then let it idle and listen.

• Exhaust manifold bolt failure / leaks (HEMI tick source #1)
  • ticking at cold start that quiets as metal warms, often reported around the 60k-mile class
• Fuel delivery service (in-tank pump / PFI injectors)
  • long crank / low rail pressure complaints on high-mileage trucks
• Ignition service wear (plugs / coils)
  • rough idle / misfire as plugs age; coils fail individually
• EGR valve carbon (gas EGR service surface)
  • EGR flow / position codes, rough idle or hesitation at light load

4Hood up and underneath

Engine off, in daylight, with a flashlight.

• Lifter / cam wear (HEMI tick source #2)
  • metallic debris in the oil on neglected cases

  To confirm: confirm constant (valvetrain) vs warm-and-quiet (exhaust) tick first - the cheap confusion is expensive

• Cooling service (water pump / thermostat)
  • weep-hole seepage / bearing noise at higher mileage

  To confirm: pressure-test the system; inspect the weep hole and bearing play

5Test drive

At least 20 minutes, including a highway run and a hill or a load if you can.

• Lifter / cam wear (HEMI tick source #2)
  • constant valvetrain tick that does not warm-and-quiet
  • misfire / dead cylinder on one bank
• Cooling service (water pump / thermostat)
  • temperature swings under tow

What it costs if you find it

Parts budgets from our repair recipes for this engine: Dave's Auto Center's prices where Dave's lists the part, approximate OEM and maker catalog prices (rounded) for the rest; labor not included. A campaign listed next to a failure may make the repair free on a covered truck: check it by VIN.