So my RV's windshield washer system has decided to become my nemesis on this road trip. The specific issue I'm experiencing is fluid running back into the reservoir after each use, which means washer fluid isn't effectively hitting bugs before they dry and smear. I actually found a clever solution - using an aquarium air pump check valve from PetSmart for just $3.00. Sometimes it's these little fixes that make a big difference.
Sometimes the washer sprays like a garden sprinkler gone rogue, other times it dribbles like a leaky faucet. The fluid seems to have a mind of its own - either freezing up in cold weather or not hitting the windshield where it's supposed to.
I'm dealing with nozzles that spray everywhere except where the bugs are, a reservoir that I can never seem to locate when it's empty, and wipers that just smear everything around instead of actually cleaning. Could someone help me troubleshoot and confirm if my check valve solution might help?
Tips for managing RV windshield washer fluid systems. Covers reservoir location, nozzle adjustment, freeze protection, and common issues.
Your aquarium check valve solution for preventing washer fluid drain-back is brilliant and exactly addresses the root cause of that frustrating bug-smearing problem. Installing a $3 one-way check valve in the washer fluid line keeps fluid at the nozzles ready for immediate spraying, eliminating the delay that causes wipers to smear dried bugs into those greasy rainbows across your windshield. This simple modification should be standard on all RVs but unfortunately isn't, making your DIY fix a game-changer for maintaining clear visibility on the road.
The check valve prevents gravity from pulling fluid back down the lines to the reservoir between uses, ensuring you get instant fluid delivery when you need it most. This is particularly crucial on RVs where the reservoir is often mounted lower than the nozzles and the lines are longer than typical passenger vehicles, making drain-back even more problematic.
The fundamental issue you've identified stems from poor OEM design that doesn't account for gravity and line length in RV washer systems. Most RV manufacturers use the same basic washer pump and nozzle setup as cars, but RVs have significantly longer fluid lines running from the reservoir (often in a basement compartment) up to windshield nozzles. When you stop using the washers, gravity pulls the fluid back down these long lines into the reservoir, leaving the nozzles and upper portions of the lines empty.
This drain-back problem is compounded by the typical RV driving environment where bugs are more prevalent than city driving, and the higher windshield position means more bug strikes. The delay between pressing the washer button and getting fluid creates that critical window where wipers activate first, spreading the bug guts before the cleaning solution arrives to break down the proteins and oils.
Additionally, many RV washer pumps are undersized compared to the line volume they need to fill, making the initial prime time even longer. The pump has to overcome not just the vertical lift but also push out any air that's entered the system through the now-empty lines.
Before installing your check valve solution, first verify that drain-back is actually your problem by checking that the pump runs, electrical connections are good, fluid level is adequate, and nozzles aren't clogged. If fluid eventually reaches the windshield after a delay (rather than no fluid at all), then drain-back is likely the issue. To install the fix, disconnect power to the washer pump by removing the washer system fuse or disconnecting the pump electrical connector to prevent accidental activation during work. Then locate your washer fluid reservoir and trace the lines to understand your specific routing. Most RVs have the reservoir in a basement compartment with lines running up through the chassis and into the dash area before going to the windshield nozzles. You'll want to install the check valve as close to the nozzles as possible while still being accessible for future maintenance.
Gather the necessary tools: basic hand tools for accessing the washer lines, possibly a trim removal tool for dashboard panels, and electrical tape or zip ties for securing the modified line. Test your current system first to confirm you're experiencing the drain-back issue - activate the washers after the RV has been sitting and time how long before fluid actually reaches the windshield.
Purchase a quality aquarium check valve rated for the pressure your washer pump produces (check your owner's manual for specifications, as most automotive washer pumps operate at 15-35 PSI). The clear plastic ones from pet stores work fine, but brass or stainless versions last longer if you can find them. Make sure the valve's flow direction arrow will point toward the nozzles when installed.
Start by accessing the washer fluid line near the windshield nozzles, which typically requires removing some dash trim or accessing the lines from behind the dashboard. Cut the main line feeding the nozzles (there may be a splitter if you have dual nozzles) and install the check valve with the flow arrow pointing toward the windshield. Note that washer fluid contains methanol and is toxic - work in a ventilated area, avoid skin contact, and properly dispose of any spilled fluid. Use appropriate hose clamps or push-on fittings depending on your line type.
The ideal location is in the highest practical point of the line run where it won't interfere with other components. This maximizes the volume of fluid retained above the valve while keeping it accessible. If your RV has a line splitter for dual nozzles, install the valve before the splitter so both nozzles benefit from the retained fluid.
Secure the modified section with zip ties or clips to prevent the check valve from moving around or creating stress points in the line. Test the installation by activating the washers - you should get immediate fluid flow. Check all connections for leaks and verify proper system operation before reinstalling any trim pieces. Let the system sit for several hours, then test again to confirm the valve is holding fluid in the upper lines.
For RVs with particularly long line runs or multiple nozzles (windshield plus side mirrors), consider installing check valves in each branch line for maximum effectiveness. The small cost is worth eliminating the frustration of smeared bugs during those critical moments when you need clear visibility most.
This modification is well within most DIY RV owner capabilities and doesn't require professional assistance. The washer system operates at low pressure and doesn't involve critical safety systems, making it a perfect weekend project. However, if you're uncomfortable working around electrical connections near the washer pump or can't access the lines due to complex dashboard disassembly, an RV service center can install the check valve in about 30 minutes.
Professional help might be worthwhile if you discover other issues during the process, such as a failing washer pump, clogged nozzles, or damaged lines that need replacement. Some RV techs might initially question the modification since it's not standard, but any experienced mechanic will understand the logic once you explain the drain-back problem you're solving.
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