Diesel Trouble Codes

Coolant Loss or White Smoke From the Exhaust — 6.4 Power Stroke

A diagnostic reference for 2008–2010 Ford 6.4L Power Stroke trucks showing coolant loss or white smoke from the exhaust. Focuses on EGR cooler failure and…

Updated October 15, 2026

What’s going on

On the 6.4L Power Stroke, coolant loss with white, sweet-smelling exhaust smoke usually means coolant is entering the exhaust or being lost externally. The platform uses coolant-cooled EGR coolers that can crack and leak coolant into the exhaust, and its radiators are a known external leak point. Many coolant leaks set no code at all.1

Most likely causes

  1. EGR cooler internal leak — The 6.4L uses coolant-cooled EGR coolers that can crack and leak coolant into the exhaust, producing white, sweet-smelling smoke and coolant loss. An EGR cooler problem can set P2457.12
  2. Radiator external leak — Radiators are a known failure point on the 6.4L with external leaks that cause coolant loss.1345
  3. Cooling system leak elsewhere — Other cooling-system components can leak coolant without setting a code.1

How to narrow it down

  1. Read stored trouble codes; P2457 may be present with EGR cooler performance issues.
  2. Inspect for external coolant leaks, especially at the radiator tank seams and connections.
  3. Check coolant level and condition; look for white, sweet-smelling smoke from the exhaust indicating coolant entering the exhaust.
  4. Inspect EGR cooler for signs of coolant intrusion or failure; the 6.4L EGR cooler is a known failure point for coolant loss and white smoke.
  5. Pressure test the cooling system to locate leaks not visible at idle.

Common mistake to avoid

Replacing the EGR valve without testing it. If the valve still moves freely, a carbon cleaning often fixes the flow code; and if it opens on command but the code stays, the blockage is in the passages or cooler, not the valve. Source: FleetRabbit — EGR valve problems and repair.

Parts and tools you may need

Tools you’ll need

Rough cost and difficulty

Likely repairPartsShop laborWho usually does it
Coolant hose or leak repair$20–$2000.5–3 hrsDIY with tools and a manual
Water pump$150–$4002–6 hrsDIY with tools and a manual
EGR cooler$400–$1,0008–15 hrsShop

Typical US independent-shop figures; labor runs about $120–$180 per hour (dealers charge more). Confirm the diagnosis before buying parts.

When to see a pro

If coolant is entering the exhaust or a high-pressure fuel system is suspected, have a qualified diesel technician diagnose and repair. Do not attempt internal repairs without proper training and safety equipment. This guide is for diagnosis only. Do not modify emissions systems.

Check for recalls

Recalls are tied to your truck’s VIN, so check yours directly: enter the VIN at NHTSA’s recall lookup. Open safety recalls are repaired free at a dealer.

Sources

  1. Curated symptom seed — 6.4 Power Stroke (curated) ↩︎ ↩︎ ↩︎ ↩︎

  2. Curated DTC seed — 6.4 Power Stroke (curated) ↩︎

  3. NHTSA owner report 10315236 ↩︎

  4. NHTSA owner report 10248262 ↩︎

  5. NHTSA owner report 10375494 ↩︎