Cummins/Onan QSX15 / QSx15 — Testing SCA Concentration Level
Testing & diagnosis · cooling system
For the Cummins/Onan QSX15 / QSx15, from the Cummins/Onan owner's manual.
Applies to: Cummins/Onan QSx15, Cummins/Onan QSX15 engine
Before you start
- Do not remove pressure cap from a hot engine; wait until coolant is below 50C [120F].
Procedure
- Ensure coolant sample is between 10 and 54 C [50-130F].
- Compare test strip pads to color chart in daylight or cool white fluorescent lighting.
- Use one strip at a time; do not touch pads.
- If concentration is below 1.2 units per gallon, replace filter and precharge with liquid.
Tools required
- CC2602 Coolant Test Kit Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Minimum 1.2 units per gallon SCA concentration
Full service-parts list: Cummins/Onan QSx15 →
Source: Cummins/Onan owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.