What tests are included in a #2 diesel fuel Summer testing package? Research Laboratories, Inc offers diesel fuel users a "Summer" test package. Testing requires a minimum of 400 mL (1 pint/16 fluid oz) of diesel fuel to complete all tests. The Summer test package includes: API Gravity Cetane Index (4-variable calculated) Carbon Residue Conductivity Density Distillation (IBP to EBP) Karl Fischer Water by Titration Microbial Pensky-Martin Flash Point (closed cup) Stability Sulfur (ASTM D5453) Viscosity SUS See the FAQ section for more information about individual tests and terminology. Click Winter for our cold weather testing package. Back To FAQs