# Thermostat initial opening temperature (NB1)

Canonical URL: https://miatatorque.com/spec/thermostat-initial-opening-temperature-nb1/

Applicability: NB 1999–2000 (BP-4W) — Other years inferred from 1999 factory evidence.

Confidence: fsm

83.5–88.0°C {183–190°F}

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": "thermostat-initial-opening-temperature-nb1",
  "name": "Thermostat initial opening temperature (NB1)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NB",
      "years": [
        1999,
        2000
      ],
      "engines": [
        "BP-4W"
      ],
      "note": "Other years inferred from 1999 factory evidence."
    }
  ],
  "kind": "non-torque",
  "value_text": "83.5–88.0°C {183–190°F}",
  "procedure": {
    "notes": "Factory single-valve thermostat specification; this source does not use the NA8 main/sub-valve values. Inspect for opening at room temperature and for opening temperature and lift; replace as necessary. Repeated in technical data 01–50–2 (PDF313)."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1999",
      "page": "01–12–5 (PDF p. 224)",
      "as_printed": "Initial-opening temperature\n°C {°F}\n83.5—88.0 {183—190}",
      "verified_years": [
        1999,
        1999
      ],
      "document": {
        "id": "fsm-1999",
        "tier": 1,
        "title": "1999 Mazda MX-5 Miata Workshop Manual",
        "covers": [
          {
            "gen": "NB",
            "years": [
              1999,
              2000
            ],
            "engines": [
              "BP-4W"
            ]
          }
        ],
        "url": "https://www.mellens.net/mazda/Mazda-Miata-1999-2001.pdf"
      }
    }
  ],
  "jobs": [],
  "system": "cooling",
  "component": "inventory-pass-2026-10",
  "componentName": "Service measurements and fasteners",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/thermostat-initial-opening-temperature-nb1/"
}
```