ASTM D7593-22 PDF

Full title and description

Standard Test Method for Determination of Fuel Dilution for In-Service Engine Oils by Gas Chromatography — Designation: ASTM D7593-22. This test method specifies a gas‑chromatographic procedure to quantify fuel dilution in in‑service lubricating oils (diesel, biodiesel and gasoline ranges) and defines procedures for sample handling, chromatographic separation and calculation of fuel dilution percentage.

Abstract

ASTM D7593-22 describes a direct gas chromatography (GC) technique for measuring the percentage of unburned fuel present in used engine oils (fuel dilution). The method permits analysis without mandatory pretreatment, uses a marker‑peak approach to separate fuel‑range components from oil‑range components, and provides quantitation ranges up to 10 % m/m for diesel/biodiesel and up to 5 % m/m for gasoline. The procedure normalizes diesel quantitation using a simulated aged fuel and documents method limitations related to fuel aging and identification.

General information

• Status: Active.
• Publication date: Current edition approved Dec 1, 2022; published January 2023 (Designation D7593-22).
• Publisher: ASTM International.
• ICS / categories: 75.100 (Lubricants, industrial oils and related products); 75.160.20 (Liquid fuels).
• Edition / version: D7593-22 (replaces D7593-14).
• Number of pages: 9 pages.

Information summarized from the ASTM D7593-22 document and published document summaries.

Scope

This test method covers the determination of fuel dilution in in‑service engine oil using gas chromatography. Analysis may be performed directly on samples without dilution or pretreatment where the sample amount falls within the linear range of the GC detector. The method defines quantitation limits (up to 10 % m/m for diesel/biodiesel and up to 5 % m/m for gasoline) and notes that the test does not reliably identify the exact fuel type in aged crankcase samples; diesel quantitation is normalized using a simulated aged fuel. Safety and regulatory applicability are left to the user to address.

Key topics and requirements

• Purpose: quantify fuel dilution (percentage of unburned fuel) in in‑service engine oils.
• Analytical principle: capillary gas chromatography with an appropriate column and detector; use of a chromatographic marker peak to separate fuel‑range from oil‑range components.
• Sample handling: analysis can be performed without pretreatment or dilution when within instrument linearity; dilution is permitted but may increase error.
• Quantitation ranges: up to 10 % (m/m) for diesel and biodiesel; up to 5 % (m/m) for gasoline.
• Calibration/normalization: diesel results normalized against a simulated aged fuel standard; guidelines provided for calibration and calculation of percent fuel dilution.
• Limitations and interpretation: fuel aging and degradation in crankcase environments can affect identification of fuel species; results indicate dilution level, not necessarily precise fuel composition.
• Referenced norms/practices: refers to ASTM terminology and chromatographic practice standards for definitions and procedures.

Key method details and limitations are taken from the standard text and official document summaries.

Typical use and users

Used by oil analysis laboratories, engine and vehicle manufacturers, fleet maintenance teams, lubricant producers, research laboratories and quality/control groups to monitor fuel dilution as part of condition‑based maintenance, root‑cause investigations and lubricant performance assessments. The method is typically applied to crankcase oil samples from diesel and gasoline engines to help decide maintenance actions or evaluate engine/fuel system issues.

Related standards

D7593-22 replaces earlier editions (D7593-14 and prior). Related ASTM practices and guides commonly referenced alongside this method include specimen sampling practices (e.g., D4057), terminology standards, and chromatographic practice standards used for method implementation and statistical assessment of results. The method was developed under Committee D02 (Petroleum Products, Liquid Fuels, and Lubricants) and appears in ASTM Volume 05.04 collections for petroleum and lubricant testing.

Keywords

fuel dilution; gas chromatography; in‑service engine oil; diesel; biodiesel; gasoline; marker peak; oil analysis; lubricant testing; ASTM D7593-22.

FAQ

Q: What is this standard?

A: ASTM D7593-22 is a gas‑chromatographic test method for determining the percentage of fuel dilution in in‑service engine oils (designation D7593-22).

Q: What does it cover?

A: It covers direct GC analysis of used engine oil to quantify unburned fuel present, including procedural notes on sample handling, chromatographic separation using a marker peak, calibration/normalization (simulated aged fuel for diesel), and quantitation limits (up to 10 % for diesel/biodiesel, up to 5 % for gasoline).

Q: Who typically uses it?

A: Oil analysis laboratories, OEMs (engine and vehicle manufacturers), fleet and maintenance engineers, lubricant manufacturers and technical service organizations use this method to detect and quantify fuel dilution for maintenance decisions and root‑cause analysis.

Q: Is it current or superseded?

A: As of the current edition, D7593-22 is the active replacement of earlier editions (it replaces D7593-14). The current edition was approved Dec 1, 2022 and published in January 2023. Users should verify whether any amendments or corrigenda have been released since that date.

Q: Is it part of a series?

A: It is part of ASTM Committee D02 activities and appears in the ASTM Volume covering Petroleum Products, Liquid Fuels, and Lubricants (Volume 05.04). The method is often used alongside other ASTM practices and guides for sampling, chromatography, and statistical assessment.

Q: What are the key keywords?

A: Fuel dilution, gas chromatography, marker peak, in‑service oil, diesel, biodiesel, gasoline, lubricant analysis, ASTM D7593-22.