RV Radiator Hose Quick Disconnect Removal: Step-by-Step Guide

The Rundown

Those two hoses plugged into your bottom radiator hose are most likely transmission cooler lines or engine oil cooler lines that run through a section of the radiator. To disconnect them, you'll need to identify whether they use spring clamps, screw clamps, or quick-disconnect fittings. Most RV applications use either spring clamps that require pliers to squeeze and slide, or quick-disconnect fittings with spring-loaded release tabs or collars. The key is to drain the radiator first and have a catch pan ready, as you'll lose some coolant when you pull that bottom hose with the integrated fittings.

Since you're changing the clutch fan assembly, you're smart to remove the bottom radiator hose completely - this gives you much better access to the fan clutch mounting bolts and prevents accidentally damaging the radiator during removal. Just make sure to mark which hose goes where before disconnecting, as mixing up transmission cooler lines can cause serious damage.

Why It Happens

RV manufacturers integrate these auxiliary cooling lines into the bottom radiator hose to save space and reduce the number of connections in the tight engine compartment. This design is especially common on Class A and Class C motorhomes where space is at a premium. The transmission cooler lines route hot transmission fluid through a section of the radiator to cool it before returning to the transmission, while oil cooler lines do the same for engine oil in heavy-duty applications.

These integrated hose assemblies are actually a smart engineering solution, but they do make maintenance more complex. The connections are designed to be removable, but they're often neglected during regular service intervals, which can make them stubborn to disconnect after years of heat cycling and exposure to road salt and debris.

Gather These Items

You'll need a few specific tools and supplies to safely disconnect these lines without damage:

• Spring clamp pliers or standard pliers (depending on clamp type)
• Drain pan capable of holding at least 1 gallon of coolant
• Shop rags or paper towels for cleanup
• Penetrating oil (PB Blaster or similar) if connections are corroded
• Hose clamps or zip ties to temporarily seal disconnected lines
• Fresh coolant for refilling (check your manual for type and capacity)
• Funnel for refilling the radiator
• Camera or phone to document hose routing before disconnection

The Fix

SAFETY WARNING: Allow the engine to cool completely before starting work. Hot coolant and pressurized systems can cause severe burns.

Start by removing the radiator cap to release system pressure, then drain the radiator through the drain petcock at the bottom - you only need to drain enough to drop the coolant level below the bottom hose connection. Position your drain pan to catch both the coolant and any transmission fluid or oil that may leak from the auxiliary lines. Once drained, take photos of the hose connections from multiple angles - this will save you headaches during reassembly.

Examine the connection points carefully. If you see spring clamps, use pliers to squeeze the ends together and slide them back away from the connection point. The hoses should then pull off with some twisting and gentle pressure. For quick-disconnect fittings, press the release tab or collar while pulling the fitting apart - they're designed to disconnect without tools when the release mechanism is activated. If they're stuck, apply penetrating oil and let it sit for 10-15 minutes before trying again.

Once the auxiliary lines are disconnected, cap or plug them immediately to prevent contamination and fluid loss. You can use rubber caps, hose clamps on folded hose ends, or even zip ties as temporary measures. Now remove the main radiator hose clamps and pull the bottom hose free. With the hose out of the way, you'll have clear access to remove the clutch fan assembly.

During reassembly, inspect all hose ends and fittings for damage or excessive wear. Replace any questionable components now rather than dealing with leaks later. Apply a thin coat of coolant to rubber sealing surfaces to help them seat properly, and don't overtighten threaded fittings - snug is sufficient.

Know Your Limits

While disconnecting these hoses is straightforward, be aware that some RV cooling systems may retain residual pressure even when cold, and the auxiliary cooling lines may contain hot fluids under pressure. If your RV has been running recently, wait at least an hour for everything to cool down before starting work. Never attempt to disconnect pressurized lines while the engine is warm.

If you encounter lines that seem permanently attached or welded into the radiator hose, stop and consult your service manual - some systems require special tools or procedures. Additionally, if you're not comfortable working with transmission or engine oil cooling systems, consider having a professional handle the auxiliary line connections while you tackle the fan clutch replacement yourself. Mixing up these lines or introducing contamination can lead to expensive transmission or engine damage that far exceeds the cost of professional help with these auxiliary cooling systems.