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SAE J20‑2 Coolant Hose – Wire‑Reinforced Convoluted Hose Specification for Normal Service
SAE J20‑2 (MAR2018) is a supplement to SAE J20 that provides ordering information for wire‑reinforced, convoluted coolant hoses (SAE 20R5 types) used in automotive engine cooling systems. Originally developed to support government procurement, it replaces portions of Federal Specification ZZ‑H‑428 and Military Drawing MS51008. Today it serves as a key reference for both public‑sector and commercial applications requiring a durable, flexible hose with embedded wire support.
Key Specifications and Requirements
All technical requirements in SAE J20‑2 are additional to the baseline SAE J20 standard. The following tables summarize the nominal lengths and inside diameters available under this standard. Tolerances for these dimensions comply with SAE J20 Table 2.
| Nominal Length (mm) | Actual Length (mm) | Actual Length (in) |
|---|---|---|
| 127 | 127.0 | 5.00 |
| 152 | 152.4 | 6.00 |
| 203 | 203.2 | 8.00 |
| 254 | 254.0 | 10.00 |
| 305 | 304.8 | 12.00 |
| 457 | 457.2 | 18.00 |
| 610 | 609.6 | 24.00 |
| 762 | 762.0 | 30.00 |
| 914 | 914.4 | 36.00 |
| Nominal ID (mm) | Actual ID (mm) | Actual ID (in) |
|---|---|---|
| 25 | 25.40 | 1.00 |
| 32 | 31.75 | 1.25 |
| 38 | 37.50 | 1.50 |
| 51 | 50.80 | 2.00 |
| 64 | 63.50 | 2.50 |
| 76 | 76.20 | 3.00 |
For government procurement, manufacturers and suppliers must be ISO 9001 or QS‑9000 certified. Marking on the hose cuffs (or on an attached tape label if space is insufficient) must include the Part Identification Number, the manufacturer’s CAGE code or trademark, and the month/year of manufacture.
🛠️ Common Mistake: Applying this standard to non‑wire‑reinforced hoses. SAE J20‑2 is specifically for wire‑reinforced convoluted types. For plain coolant hoses, refer to the base SAE J20 standard.
Part Identification and Cross‑Reference
Part numbers under SAE J20‑2 follow the format illustrated in Figure 1 of the standard (see below). The construction identifies the standard, hose type (EC, HT, LT, or combinations), class, and size. This numbering system directly replaces the older part numbers from MS51008 and ZZ‑H‑428.
SAE-J20/2ECLT A – (Type EC, HT, LT; Class A)
| J20 Designation | J20 Class | ZZ‑H‑428 Type | ZZ‑H‑428 Grade | ZZ‑H‑428 Class |
|---|---|---|---|---|
| SAE‑J20/2ECLT | A | V | A | 2 |
| SAE‑J20/2EC | B | V | B | 1 |
| SAE‑J20/2EC | C | V | B | 2 |
| SAE‑J20/2EC | D‑1 | V | B | 3 |
| SAE‑J20/2EC | D‑3 | V | B | 4 |
The hose must contain a wire helix or helices embedded in the convoluted section, with plain ends for connection. This design provides the necessary collapse resistance while maintaining flexibility for routing in tight engine compartments.
🔍 Engineering Design Insight: The combination of convoluted profile with internal wire support allows the hose to withstand vacuum and moderate pressure without kinking. Wall gauge and tolerances are governed by SAE J20, ensuring consistent performance across suppliers.
Frequently Asked Questions
- What are the nominal lengths and inside diameters available?
Lengths range from 127 mm (5 in) to 965 mm (38 in); inside diameters from 25 mm (1 in) to 76 mm (3 in). See Tables 1 and 2 above. - What marking is required for government use?
The hose must show the Part Identification Number, the manufacturer’s CAGE code or trademark, and the month/year of manufacture. If space is insufficient, a taped label can be used. - What certifications must suppliers hold?
For government procurement, suppliers must be ISO 9001 or QS‑9000 certified. - How do I construct a part number?
Follow the format in Figure 1 of SAE J20‑2. The part number includes the standard identifier, hose type(s), and class (e.g., SAE‑J20/2ECLT A).
For sizes and tolerances not listed in this document, supplier and purchaser may agree on alternative dimensions provided all other requirements of SAE J20 are met.
Specifiers should verify whether the document has been updated since its stabilization in 2018, as newer technology may be available.
