# Engine coolant type and antifreeze mixture (NA6)

Canonical URL: https://miatatorque.com/spec/coolant-type-and-mixture-na6/

Applicability: NA 1990–1993 (B6) — Other years in this family inferred from 1990 factory evidence with owner approval; actual-year verification is separate.

Confidence: fsm

Ethylene glycol-based coolant mixed with soft (demineralized) water; By volume: 35% coolant / 65% water for protection above −16°C (3°F); 45% / 55% above −26°C (−15°F); 55% / 45% above −40°C (−40°F). Do not use alcohol- or methanol-based coolant.

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": "coolant-type-and-mixture-na6",
  "name": "Engine coolant type and antifreeze mixture (NA6)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NA",
      "years": [
        1990,
        1993
      ],
      "engines": [
        "B6"
      ],
      "note": "Other years in this family inferred from 1990 factory evidence with owner approval; actual-year verification is separate."
    }
  ],
  "kind": "fluid",
  "fluid": {
    "type": "Ethylene glycol-based coolant mixed with soft (demineralized) water",
    "notes": "By volume: 35% coolant / 65% water for protection above −16°C (3°F); 45% / 55% above −26°C (−15°F); 55% / 45% above −40°C (−40°F). Do not use alcohol- or methanol-based coolant."
  },
  "procedure": {
    "notes": "Never remove the radiator cap with the engine hot. Ratios are coolant/water volume percentages, not a universal fixed mixture."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1990",
      "page": "E–5 (PDF p. 135)",
      "as_printed": "Antifreeze solution mixture percentage\nCoolant protection\nVolume percentage\nWater\nCoolant\nGravity at 20°C (68°F)\nAbove −16°C (3°F) 65 35 1.054\nAbove −26°C (−15°F) 55 45 1.066\nAbove −40°C (−40°F) 45 55 1.078\nFill with the proper amount and mixture of ethylene glycol-based coolant by referring to the table above.",
      "verified_years": [
        1990,
        1990
      ],
      "fluid": {
        "type": "Ethylene glycol-based coolant mixed with soft (demineralized) water",
        "notes": "By volume: 35% coolant / 65% water for protection above −16°C (3°F); 45% / 55% above −26°C (−15°F); 55% / 45% above −40°C (−40°F). Do not use alcohol- or methanol-based coolant."
      },
      "document": {
        "id": "fsm-1990",
        "tier": 1,
        "title": "1990 Mazda MX-5 Miata Workshop Manual",
        "part_number": "1193-10-89C",
        "covers": [
          {
            "gen": "NA",
            "years": [
              1990,
              1990
            ],
            "engines": [
              "B6"
            ]
          }
        ],
        "url": "https://archive.org/details/1990-mazda-mx-5-miata-workshop-manual_202411"
      }
    }
  ],
  "jobs": [],
  "system": "cooling",
  "component": "gap-followup-2026-10",
  "componentName": "Additional factory manual gap audit",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/coolant-type-and-mixture-na6/"
}
```