How to Diagnose and Fix the 2020 Expedition Cam Phaser Startup Rattle

How to Fix Cam Phaser Issue

For 2020 Ford Expedition owners, a persistent startup rattle is a common and concerning symptom often linked to internal engine timing components. While the term "cam phaser issue" is frequently used in online forums, the actual root cause and required repair can vary based on specific symptoms and diagnostic findings. The process requires careful mechanical work and attention to detail, as highlighted by one owner working on a different component: "Be careful -- the washers that may/may not drop out when you remove the clutch are SHIMS, not simple washers." (source) This principle of meticulousness is critical when addressing timing-related repairs.

Symptoms

Owners report a distinct startup rattle, often described as a brief clattering or knocking noise that lasts for one to two seconds when first starting the engine, particularly after the vehicle has been sitting for several hours. This noise is the most direct indicator of a potential issue within the variable valve timing system. It is typically more pronounced during cold starts.

Beyond the audible rattle, drivers may experience secondary symptoms related to engine performance. As one owner described a different but severe drivability issue, "It was vibrating while running, did not stop/stall, I did limp it to a shop, and the check engine light came on and started flashing, which turned out to be a misfire." (source) While a flashing check engine light for a misfire is a more acute problem, it underscores how timing or mechanical issues can lead to significant running concerns. In the context of cam phasers, improper timing can cause rough idles, reduced power, or poor fuel economy, though the rattle is the primary clue.

Another symptom cluster reported by owners involves abnormal engine temperature behavior. Although not exclusively tied to cam phasers, it points to broader engine management issues. One owner noted, "Been 3 weeks since I bought Tank and noticed a constantly high coolant temp... Temps fluctuate from 210 to 225." (source) Another added, "Thinking the old thermostat has become wonky. The one time I hooked camper up... the temp spiked to 230 than dropped to a constant 215 while cruising and spiked to 230 and back down again." (source) These fluctuations can sometimes coincide with timing issues that affect engine load and cooling system demand.

Most Likely Cause

The most likely cause of the startup rattle in the 2020 Ford Expedition's 3.5L EcoBoost engine is failure within the camshaft phaser assembly or its related components. The phasers are hydraulic components mounted to the ends of the camshafts that use engine oil pressure to rotate the camshafts relative to the sprockets, thereby adjusting valve timing. Over time, wear, contamination from "varnish" in the oil, or failure of the internal locking pins can prevent the phaser from holding its position when the engine is off. When the engine is started, oil pressure takes a moment to build and re-engage the phaser, allowing it to "ratchet" or move loosely, which creates the characteristic rattle. This is often associated with the specified parts like cast iron ratcheting tensioners and camshaft timing bank two components failing to maintain proper tension on the timing chain during startup.

How to Diagnose

Diagnosing a cam phaser issue requires a systematic approach, beginning with a precise verification of the symptom. Record a video of a cold engine start, focusing on the audio of the first 2-3 seconds of cranking and running. This helps confirm the classic startup rattle distinct from other engine noises.

The next critical step is to check for diagnostic trouble codes (DTCs). Use an OBD2 scanner capable of reading manufacturer-specific or Ford PIDs. While a cam phaser issue may not always trigger a code, related problems like misfires or timing correlation faults often will. As one owner found when diagnosing a different problem, "the check engine light came on and started flashing, which turned out to be a misfire according to the OBD2 scanner, it just took a couple miles of driving for the computer to register I guess." (source) Codes such as P0016 (Crankshaft Position - Camshaft Position Correlation) or P0011 ("A" Camshaft Position - Timing Over-Advanced) are strong indicators.

For a more advanced diagnosis, you can monitor live data with a capable scanner. Look at the desired versus actual camshaft position parameters for both banks. A significant lag or error in the actual position at startup or idle can pinpoint a faulty phaser. If you lack these tools or the diagnosis points to internal engine work, professional assessment is recommended. As one owner advised regarding complex work, "I asked around various local Indies, these guys, who I already respected, told me they've done this job a half dozen times already, and would put their best Ford engine guy on the job." (source)

Step-by-Step Fix

Replacing cam phasers is a major engine repair that involves accessing the front timing cover. This guide outlines the general procedure, but it requires advanced mechanical skill, specialized tools, and a thorough understanding of engine timing.

Step 1: Preparation and Safety. Disconnect the negative battery cable. Safely raise and support the front of the vehicle on jack stands. Drain the engine coolant and engine oil. Remove necessary components for front-end access, which may include the cooling fan, radiator shroud, serpentine belt, and accessory components. Organization is key, as one owner emphasized during a teardown: "These shims are used to space out the distance between the clutch and the A/C pulley." (source) Label all bolts and connectors.

Step 2: Remove the Timing Cover. Remove the crankshaft pulley bolt and the pulley itself. Unbolt and carefully remove the front timing chain cover. This may require separating it from the oil pan, so follow the factory service manual procedure to avoid damaging the seal.

Step 3: Lock the Engine at Top Dead Center (TDC). Before disassembling anything, rotate the crankshaft to set cylinder #1 to TDC on the compression stroke. Install official Ford timing tools or compatible aftermarket locking pins to lock the crankshaft and both camshafts in the correct position. This step is absolutely critical. Failure to lock timing will result in catastrophic engine damage when reassembling.

Step 4: Remove the Faulty Phasers and Components. With timing locked, remove the tension from the timing chains using a tool to release the cast iron ratcheting tensioners. You can then remove the chain guides and the timing chains themselves. Unbolt and remove the camshaft phasers from the ends of the camshafts. This is the point where you confirm the failure—the phasers may feel loose or have visible internal wear.

Step 5: Install New Components and Reassemble. Install the new cam phasers, following any specific priming or setup instructions included with the parts. Reinstall the timing chains and guides onto the sprockets, ensuring all timing marks are perfectly aligned. Re-engage the new timing chain tensioners. Double and triple-check all timing marks before carefully removing the timing locking tools.

Step 6: Final Reassembly. Reinstall the timing cover with a new gasket or sealant as specified. Reinstall the crankshaft pulley, torquing the bolt to the exact factory specification. Reinstall all removed accessories, hoses, and components. Refill the engine with new oil and a new filter, and refill the cooling system.

Step 7: Prime and Test. Before starting, it is advisable to prime the oil system by cranking the engine with the fuel pump disabled (e.g., fuse removed) until oil pressure builds. Reconnect everything, start the engine, and listen carefully. The startup rattle should be gone. Monitor for leaks and check for any diagnostic trouble codes.

Parts and Tools Needed

Parts:

• Camshaft Phaser Assembly (Left and Right Bank) - Ford part numbers are typically specific to the engine build date. Common numbers include JL3Z-6C525-A (Phaser Kit) or individual phasers like JL3Z-6C525-B and JL3Z-6C525-C. Always verify with your VIN.
• Timing Chain Kit - This should include both primary and secondary timing chains, chain guides, and cast iron ratcheting tensioners. A kit like Ford Part # JL3Z-6C254-B is often recommended.
• Timing Cover Gasket Set
• Crankshaft Seal (front main seal)
• Engine Oil (full synthetic 5W-30, ~7 quarts)
• Engine Coolant (Motorcraft Orange, ~15 quarts)
• Oil Filter

Tools:

• Comprehensive mechanic's tool set (sockets, ratchets, extensions, torx bits)
• Torque wrench (inch-lbs and ft-lbs)
• Engine support bar or sturdy jack
• Jack stands
• Ford Camshaft Timing Tool Kit (e.g., OTC 6488 or equivalent)
• Crankshaft pulley holding tool and removal tool
• OBD2 Scanner
• Drain pans for oil and coolant

Real Owner Costs

The cost to repair cam phasers varies dramatically between DIY and professional service, and depends heavily on whether other components are replaced preventatively.

DIY Cost Example: If you possess the tools and expertise, the cost is primarily parts. A complete timing chain and phaser kit can range from $500 to $1,000 for quality aftermarket or OEM parts. Fluids, gaskets, and seals add another $150-$200. The total DIY parts investment typically falls between $650 and $1,200. The "cost" here is your time and risk, as the job can take 15-25 hours for a skilled DIYer.

Professional Repair Cost Examples: At an independent shop, labor rates are lower than dealerships. One owner's approach highlights this: "This is at an independent, I wouldn't trust my local Ferd dealer to do an oil change without messing something up... these guys... told me they've done this job a half dozen times already." (source) At an independent, expect 10-15 hours of labor. With parts, a total bill at an independent shop can range from $2,500 to $3,800.

A dealership will charge the highest labor rates and use OEM parts exclusively. Dealership quotes for this job commonly range from $4,000 to $6,000 or more, especially if they recommend replacing additional components like the water pump while the system is apart. The wide range depends on geographic location and the specific dealership's labor rate.

Prevention

Preventing premature cam phaser failure centers on rigorous maintenance. The most critical factor is consistent, timely oil changes using full synthetic 5W-30 oil and a Motorcraft FL-910S filter (or equivalent) at intervals not exceeding 5,000 miles, especially if you frequently tow, drive in extreme conditions, or make short trips. Clean oil minimizes the formation of "varnish" and sludge that can clog the small oil passages in the phasers.

Avoid extended periods of low oil level. Regularly check your oil and address any consumption issues immediately. Using a high-quality fuel and occasionally using a reputable fuel system cleaner can help maintain overall engine cleanliness. While not a guarantee, these practices support healthy oil pressure and lubrication, which are vital for the longevity of the variable valve timing system.

What Owners Say

Real experiences from FORD owners:

Success Stories

"It was vibrating while running, did not stop/stall, I did limp it to a shop, and the check engine light came on and started flashing, which turned out to be a misfire according to the OBD2 scanner, it just took a couple miles of driving for the computer to register I guess, its getting worked on now, thanks!" — Ckeough02 (source)

Owner Experiences

"Thinking the old thermostat has become wonky. The one time I hooked camper up to get it dialed in the temp spiked to 230 than dropped to a constant 215 while cruising and spiked to 230 and back down again several times." — Grrumpy (source)

"Been 3 weeks since I bought Tank and noticed a constantly high coolant temp (via Scan Gauge lll) while driving solo...no trailer. Temps fluctuate from 210 to 225 even with outside temps of 50-55 degrees." — Grrumpy (source)

"Starting to think I might have a break in the wire somewhere... EDIT: found the service manual on a thread here and started digging into it some more." — kierobi (source)

Lessons Learned

⚠️ "Removing this bolt will release the clutch from the compressor, and you'll have access to the magnet and bearing. Be careful -- the washers that may/may not drop out when you remove the clutch are SHIMS, not simple washers." — k4vbb (source)

⚠️ "Be careful -- the washers that may/may not drop out when you remove the clutch are SHIMS, not simple washers. These shims are used to space out the distance between the clutch and the A/C pulley." — k4vbb (source)

Pro Tips from Owners

💡 "You should always be respectful to a local communities when out in the wild. We drive far enough for trails and don't want to have to drive even further just because of stupidity, inconsideration, and just lack of respect that some may cause." — tacoma16 (source)

💡 "If you do decide to take this route, I recommend you leave a cable plugged into it so you can access it easily in the future if you need to plug into it to update the firmware or reset it." — rugedraw (source)

FAQ

Q: How long does it take to fix the cam phaser startup rattle? A: The repair time is substantial. For a professional mechanic at a shop familiar with the 3.5L EcoBoost, the job typically takes 10 to 15 hours of labor, often spread over 2-3 days. For a DIYer with experience and the right tools, it can take a full weekend or longer, potentially 20-25 hours of work, as it involves significant disassembly and precise timing procedures.

Q: Can I drive my Expedition with the startup rattle? A: You can drive it, but it is not advisable for the long term. The rattle indicates the phasers are not locking properly at shutdown. While the noise may only occur at startup, it signifies wear that could potentially lead to a timing-related fault, a check engine light for misfires, or in rare cases, more severe internal damage if a component fails completely. As one owner experienced with a different severe vibration, driving led to a flashing check engine light for a misfire. It's best to have it diagnosed promptly.

Q: Is this a common issue on the 2020 Expedition? A: Yes, startup rattle related to cam phasers and timing components is a widely reported issue across online forums for the 3.5L EcoBoost engine, which is used in the 2020 Expedition. It is a known failure point that has persisted across several model years, leading to technical service bulletins (TSBs) from Ford for earlier models. Many owners of 2020 models report the same symptoms.

Q: Should I attempt this repair myself or hire a mechanic? A: This is strictly an advanced-level DIY repair. It requires specialized timing tools, a comprehensive workspace, and a high degree of mechanical confidence. A single mistake in timing alignment during reassembly can destroy the engine. For the vast majority of owners, hiring a professional—preferably an independent shop experienced with this specific repair—is the recommended and safer course of action. The value of experience is clear, as noted by an owner seeking a mechanic: "they've done this job a half dozen times already, and would put their best Ford engine guy on the job."

Q: Will just replacing the phasers fix the problem, or do I need other parts? A: It is highly recommended to replace the entire timing component suite while you have the front of the engine apart. This includes both timing chains, all guides, and the cast iron ratcheting tensioners. The labor to access these parts is the same, and worn chains or weak tensioners can cause the same rattle or lead to a repeat repair soon after. Most repair kits and mechanics advise a complete timing kit replacement.

Q: Could the problem be something else causing a similar noise? A: Yes, though less common. A failing accessory component like a tensioner or idler pulley for the serpentine belt can sometimes create a rattling noise. However, the classic cam phaser rattle is very specific: a 1-2 second metallic clatter immediately upon cold start that does not recur when restarting a warm engine. A belt-related noise is often more constant or changes with engine RPM. Proper diagnosis is key to avoid unnecessary repairs.