Ford 6.7 Coolant-Loss Evidence: matched application, confirmed loss or indication, and verified repair evidence.

Ford 6.7 Power Stroke Coolant Loss: Evidence Before Parts

by Advanced Truck Parts on Nov 04, 2026 Categories: Parts & Maintenance

Back to the ATP Garage guide libraryFord / 6.7 Power Stroke / Coolant-loss evidence

Quick answer: Narrow a commercial Ford 6.7 Power Stroke coolant complaint by identifying the actual truck, affected cooling circuit, repeat level change and localized test finding. Separate lost coolant from a gauge reading. A wet area or high gauge alone does not identify a pump, radiator, hose or internal leak.

Application: The 2024 F-650/750 manual distinguishes engine and secondary systems. TSB 18-2325 is a separate 2015-2017 F-Super Duty primary-pump case with an engine-build cutoff; TSB 25-2022 is a 2023 F-Super Duty chassis-cab gauge case. SSM 47740 has its own model/build limits.

Which truck and cooling circuit are being assessed?

Start with VIN, full truck model, model year, installed engine/build and emissions record. Note recent cooling work or engine replacement. Identify the reservoir and circuit involved using the actual vehicle information; keep photos and observations attached to that circuit. Use the commercial Ford 6.7 identification guide if those records are incomplete.

The 2024 F-650/750 6.7L diesel manual treats engine and secondary systems separately and calls for cold-level checks. It warns against opening a hot, running cooling system, unspecified sealants and incorrect coolant. Follow the truck's warning response and matching manual; do not open a hot cap to collect evidence. [1]

A service report should name the circuit tested rather than simply say "cooling system checked." Ask which condition and method were used and which area was inspected. A result from one circuit or one operating condition should retain that description in the report.

What should the coolant-loss record show?

Observation	Record to preserve	Question for the service provider
Level change	Named reservoir, comparable cold readings, date and amount added	Is the change repeatable under comparable conditions?
Visible liquid	Fresh origin, location and surrounding runoff	Which component or joint is actually leaking?
High gauge	Display, warning messages, conditions and complete code report	Is there verified overheating, loss or a separate indication issue?
Recent repair	Work performed, refill record and subsequent observations	Which part of the history belongs with the current test?
No external source confirmed	Test method, conditions, results and unresolved paths	What further evidence supports the proposed repair?

Describe whether the complaint appeared during towing, idling, a cold start or after service. Preserve the first observation as well as later changes. Photograph an accessible fresh leak origin when safe, not only the lowest wet point. If the origin is uncertain, record that uncertainty rather than naming the component nearest the puddle.

Ask for the completed finding before an order. "Low coolant," "pump area wet" and "pump leakage confirmed by the applicable test" are different statements. A useful report connects the observed loss with a named assembly and explains what remains unresolved.

What does the October 2018 primary-pump bulletin actually cover?

TSB 18-2325 covers 2015-2017 F-Super Duty 6.7L engines built on or before June 1, 2017. Its diagnostic gates include low coolant, contamination assessment and a matched pressure test confirming leakage at the primary pump. If those findings do not match, it directs normal diagnosis. It supersedes 18-2240. [2]

Keep the engine-build evidence and actual leak finding with the repair request. The dated document is not a reason to order a pump for every truck in the model-year range, or to transfer its application to F-650/F-750. Request current matching service information rather than copying the old parts list or choosing a universal test pressure.

Can a high temperature gauge be a separate complaint?

February 6, 2025 TSB 25-2022 concerns North American 2023 F-Super Duty 6.7L chassis cabs: high-normal gauge indication while towing in high ambient temperatures, without PCM DTCs or IPC warnings. It identifies a scoped IPC-software possibility and relevant update history. This does not dismiss a real leak or prove every high gauge is false. [3]

Keep the display photograph, operating conditions, measured findings and all messages together. If coolant is actually disappearing or a warning occurs, preserve that evidence separately. Ask the provider to explain which findings support the repair; a gauge case does not establish a water-pump, thermostat or radiator failure.

Why should coolant identity be recorded beyond color?

SSM 47740 identifies 2018-2019 F-Super Duty and 2019 F-650/F-750 vehicles built on or after July 9, 2018 for its Yellow-coolant case. It notes fluorescent dye can make Yellow appear green. Color alone therefore cannot establish the required specification for an unidentified truck. [4]

Preserve the product record, known mixing or top-up history and the provider's concentration or contamination finding. If the history is unknown, say so. Ask which current vehicle-specific coolant information applies. Do not infer a flush, additive, conversion or replacement schedule solely from appearance or a broad model-year search.

What should accompany the confirmed parts request?

Send the truck and installed-engine record, affected circuit, localized finding and complete component photographs. Ask the provider to name the requested assembly and explain the evidence supporting replacement. A pressure-test result should retain its setup, conditions and applicable limit; this guide supplies no test-pressure or holding-time specification.

Agree on how the repair will be checked against the original complaint. Keep the completed post-repair finding, level record and any remaining warnings with the work order. If the original event could not be reproduced, record that limitation rather than describing an unverified outcome as a completed diagnosis.

Common commercial Ford 6.7 questions

Does a high gauge alone prove coolant is being lost?

No. Preserve level observations and measured findings separately from the displayed indication.

Does TSB 18-2325 cover every 2017 6.7L truck?

No. Match F-Super Duty, the stated engine-build cutoff and its confirmed primary-pump finding.

Can the F-Super Duty pump case be transferred to F-650/F-750?

That bulletin does not establish such coverage. Use current matching information for the actual truck.

Does green appearance identify the coolant specification?

No. The scoped Ford message notes Yellow coolant can appear green; use vehicle-specific information and the product record.

Does one negative pressure test settle every loss complaint?

Keep its circuit, setup and conditions. Ask which unresolved paths or operating conditions still need assessment.

Which pressure should be used on an unidentified Ford 6.7 cooling system?

Use the current procedure and limit for the actual truck and circuit. No universal value is supplied here.

Manufacturer sources and application limits

These sources support the stated applications. Dated bulletins do not establish a diagnosis, current coverage or component interchange for an unidentified truck. Current matching service information governs the repair.

Send the truck and component record

Use the fitment verification form with VIN, full truck model, installed engine/build and emissions details, component photos and the confirmed repair request. No ATP product fitment or stock is established by this guide.