# Radiator cap pressure test (NB2 and Mazdaspeed)

Canonical URL: https://miatatorque.com/spec/radiator-cap-test-pressure-nb2/

Applicability: NB 2001–2005 (BP-Z3) — Other years inferred from 2003 factory evidence.; NB 2004–2005 (BP-Z3-TURBO) — 2005 factory technical data explicitly includes BP WITH TC; 2004 inferred within MSM family.

Confidence: fsm

94–122 kPa {0.95–1.25 kgf/cm², 13.5–17.7 psi}; hold 10 s

Always confirm against your factory manual. Match every restriction and follow all stages and procedure notes. Disputed claims must not be automatically resolved. The complete record below preserves every printed unit, source claim and procedure.

```json
{
  "id": "radiator-cap-test-pressure-nb2",
  "name": "Radiator cap pressure test (NB2 and Mazdaspeed)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NB",
      "years": [
        2001,
        2005
      ],
      "engines": [
        "BP-Z3"
      ],
      "note": "Other years inferred from 2003 factory evidence."
    },
    {
      "gen": "NB",
      "years": [
        2004,
        2005
      ],
      "engines": [
        "BP-Z3-TURBO"
      ],
      "note": "2005 factory technical data explicitly includes BP WITH TC; 2004 inferred within MSM family."
    }
  ],
  "kind": "non-torque",
  "value_text": "94–122 kPa {0.95–1.25 kgf/cm², 13.5–17.7 psi}; hold 10 s",
  "procedure": {
    "notes": "With the cap removed from a cool engine, attach to a cap tester with the proper adapter. Apply pressure gradually; it must stabilize within specification and hold for 10 s. This is a cap test, not a system leak-test pressure. The actual 2005 engine technical-data table explicitly includes BP and BP WITH TC; the displayed setting applies to both."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-2003",
      "page": "Radiator Cap Inspection (PDF p. 660)",
      "as_printed": "Pressure\n94—122 kPa {0.95—1.25 kgf/cm², 13.5—17.7 psi}",
      "verified_years": [
        2003,
        2003
      ],
      "document": {
        "id": "fsm-2003",
        "tier": 1,
        "title": "2003 Mazda MX-5 Miata Workshop Manual (electronic manual capture)",
        "covers": [
          {
            "gen": "NB",
            "years": [
              2003,
              2003
            ],
            "engines": [
              "BP-Z3"
            ]
          }
        ],
        "note": "Normally aspirated BP procedures audited; turbo procedures are covered separately."
      }
    },
    {
      "source": "fsm-2005",
      "page": "Engine Technical Data; Radiator Cap Inspection (PDF p. 751) (PDF p. 1047)",
      "as_printed": "Radiator cap valve opening pressure\n(kPa {kgf/cm², psi})\n94—122 {0.95—1.25, 13.5—17.7}",
      "verified_years": [
        2005,
        2005
      ],
      "document": {
        "id": "fsm-2005",
        "tier": 1,
        "title": "2005 Mazda MX-5 Miata Workshop Manual (electronic manual capture)",
        "covers": [
          {
            "gen": "NB",
            "years": [
              2005,
              2005
            ],
            "engines": [
              "BP-Z3"
            ]
          },
          {
            "gen": "NB",
            "years": [
              2005,
              2005
            ],
            "engines": [
              "BP-Z3-TURBO"
            ],
            "trans": [
              "6MT"
            ]
          }
        ]
      }
    }
  ],
  "jobs": [],
  "system": "cooling",
  "component": "inventory-pass-2026-10",
  "componentName": "Service measurements and fasteners",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/radiator-cap-test-pressure-nb2/"
}
```