Mack RL Radiator Coolant Hose: A Guide for 1981-1987 Models
Keep your Mack RL's engine cool and prevent breakdowns by understanding when and how to replace your radiator hoses.
- Radiator hose failure on a Mack RL is a serious issue that can lead to critical engine damage from overheating.
- Inspect hoses regularly for cracks, bulges, and leaks. Replace them if they feel brittle or spongy.
- Quality aftermarket brands like Gates are a reliable choice, as OEM parts for this truck are likely unavailable.
- Always replace hoses in pairs (upper and lower) and use new hose clamps to ensure a complete and lasting repair.
Signs of a Failing Radiator Hose
Radiator hoses are not permanent parts. The rubber material breaks down over time from the harsh environment of an engine bay. For a hard-working truck like a Mack RL, regular inspection is key. If a hose fails, it can lead to rapid coolant loss and catastrophic engine damage. Look for these warning signs:
- Visible Damage: Check for cracks, splits, or brittle, hardened sections on the hoses. Oil contamination can also cause the rubber to become soft and spongy.
- Bulging or Swelling: If a hose looks swollen, it means its internal reinforcing layers have failed. This is a serious warning sign that the hose could burst at any moment.
- Coolant Leaks: Puddles of green or yellow fluid under your truck are a sure sign of a leak. You may also notice a sweet smell from the engine bay or see crusty, colored residue around the hose clamps.
- Engine Overheating: A temperature gauge climbing into the red can be caused by a lack of coolant from a leak. It can also be caused by a collapsed lower radiator hose, which can happen if the internal spring weakens and the hose gets sucked shut by the water pump.
Do Not Delay Replacement
A failed radiator hose is a primary cause of engine overheating. Driving with a bad hose can lead to severe engine damage, including warped cylinder heads or a cracked block, resulting in expensive repairs.
Choosing the Right Aftermarket Hose: OEM vs. Aftermarket
For a vehicle from the 1980s, finding original equipment manufacturer (OEM) hoses can be difficult or impossible. Fortunately, modern aftermarket hoses from reputable brands are an excellent choice and are often made with materials that meet or exceed the original specifications.
Gates is a well-regarded, top-tier brand for aftermarket belts and hoses in the heavy-duty truck industry. Their hoses are typically made from EPDM rubber, which is engineered to resist electrochemical degradation—a leading cause of internal hose failure. They are designed to handle temperatures from -40°F to +257°F and meet SAE J20R4, Class D2 standards, making them a durable choice for the high-heat conditions of a Mack RL.
Some replacement hoses for the Mack RL are designated as "cut-to-fit." This means you will need to carefully measure and trim the new hose to match the exact length of the one you are replacing.
Estimated Replacement Costs
Replacing radiator hoses is a critical but relatively affordable maintenance task. The main costs are the parts and, if you choose, professional labor. Labor rates for heavy-duty trucks are typically higher than for passenger cars.
| Part or Service | Estimated Cost |
|---|---|
| New Aftermarket Hoses (Gates) | $35.92 - $101.28 |
| Shop Labor | $150 - $300 |
Frequently Asked Questions (FAQ)
Should I replace both radiator hoses at the same time?
Yes. Both hoses have been exposed to the same age, heat, and pressure. If one has failed, the other is likely near the end of its service life. Replacing them together is a smart preventive measure that saves you from a future breakdown.
Do I need to replace the hose clamps?
Yes, it is highly recommended to replace the hose clamps every time you install new hoses. Old clamps can lose their tension over time and may not provide a secure seal, leading to leaks.
Can I replace the radiator hoses myself?
For a mechanic with basic tools and experience, this is a manageable DIY job. The process involves draining the cooling system, removing the old hoses and clamps, installing the new parts, and then refilling and bleeding the system of any air pockets. Be prepared to handle a large volume of coolant.
Were there any recalls for Mack RL radiator hoses?
No specific recalls or technical service bulletins (TSBs) related to radiator coolant hoses were found for the 1981-1987 Mack RL during research. Failures are typically due to normal wear and tear.
Technical Specifications
OEM Part Numbers: 11MF2373P1 11MF2373P12 11MF2373P13 11MF2373P18 11MF2373P2 11MF2373P20 11MF2373P21 11MF2373P22 11MF2373P24 11MF2373P25 11MF2373P28 11MF2373P29 11MF2373P31 11MF2373P33 11MF2373P34 11MF2373P36 11MF2373P4 11MF2373P40 11MF2373P8 11MF3574M16 11MF3574M17 11MF3574M5
Material: EPDM Rubber; Temperature Range: -40°F to +257°F (-40°C to +125°C); Standard: Meets SAE 20R4, Class D2. Some hoses may be molded and require being cut to fit.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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