Stop Your Mustang's Oil Consumption: The Real Valve Cover Fix

How to Fix Valve Cover Issue

For 2020 Ford Mustang owners, a common engine issue revolves around the valve cover and its associated PCV (Positive Crankcase Ventilation) system. This isn't about a cracked cover, but a design characteristic of the plastic OEM valve covers that can lead to noticeable symptoms like oil consumption and rough running. The core of the problem is where the PCV system draws its air from inside the valve cover. As one owner with direct experience explained, "The OEM plastic valve covers have the intake port for the PCV at the back end so under hard braking and acceleration you’ll suck some oil through." This guide will walk you through identifying, diagnosing, and resolving this specific oil-control issue based on real owner experiences.

Symptoms

Owners dealing with this valve cover-related PCV issue report a specific set of symptoms that can be confusing if you don't know the root cause. The most common complaint is unexplained oil consumption. You might find yourself adding oil between changes without seeing any obvious leaks on your garage floor. This happens because oil is being pulled into the intake and burned during combustion.

Another key symptom is related to engine performance and idle quality. While not always a glaring misfire, you may experience a subtle rough idle, especially when the engine is under specific conditions. The "popping" or "buzzing" sensation some owners describe at idle, particularly after a cold start or when stopped, can be linked to an imbalance in the air/fuel mixture caused by excess oil vapor being introduced into the intake. As one owner learning about their car noted, they "was told to watch out for... rough idling/buzzing on cold start and idling at stops it will buzz as well." This advice, while for a different model year, highlights the idle irregularities associated with engine breathing problems.

Internally, the issue manifests as unwanted buildup. The oil being sucked through the PCV system leaves behind varnish and deposit buildup on intake valves, throttle bodies, and within the intake manifold itself. Over time, this can degrade performance and fuel economy. Furthermore, the area around the valve cover, particularly on the driver side, can accumulate more dirt and grime as a thin mist of oil escapes and collects dust, making the engine bay look dirtier than it should.

Most Likely Cause

The primary cause of these symptoms is the factory design of the OEM plastic valve covers and the placement of the PCV system's intake port. In the standard configuration, the port that pulls crankcase vapors into the intake is located at the rear of the valve cover baffle. This placement is problematic during dynamic driving. Under hard acceleration, oil sloshes to the back of the engine. Under heavy braking, it surges forward. With the PCV intake at the back, it can easily ingest liquid oil during these maneuvers instead of just vapors.

This design flaw turns the PCV system, which is meant to relieve pressure and recycle vapors, into an oil siphon. The PCV valve itself, while a critical component, is often not the faulty part; it's simply doing its job of allowing flow from a poorly designed source. The ingested oil then travels through the PCV hose directly into the intake manifold, where it coats components, burns in the cylinders, and leads to all the symptoms described. An intake leak downstream from this point can exacerbate the issue by creating additional vacuum that pulls even more oil through the system, but the root cause remains the valve cover port placement.

How to Diagnose

Diagnosing this issue requires a systematic approach to confirm oil is being pulled through the PCV system. You don't need advanced diagnostic tools, but a keen eye and some basic mechanical sense are essential.

First, perform a visual inspection. With the engine cool, open the hood and locate the PCV hose running from the valve cover (typically on the driver side) to the intake manifold. Disconnect it at both ends. Check inside the hose and at the ports on the manifold and valve cover for signs of wet, liquid oil. A small amount of oily residue is normal, but pooled oil or a consistently wet hose is a strong indicator. Also, inspect the area around the valve cover gasket, especially on the driver side, for excessive dirt caking, which suggests oil seepage or misting.

Next, investigate internally. Remove the intake air tube from the throttle body and look inside the intake manifold as far as you can see. Use a bright flashlight and a small inspection mirror. You are looking for a shiny, varnish buildup on the throttle body blade and the walls of the intake. This is the residue from the oil vapor. For a more definitive check, as one owner suggested in a different context, the most revealing method is to "drop the oil pan and take a look," but for this issue, a simpler step is to check your spark plugs. Removing a plug or two (cylinders 1, 2, 7, or 8 are often most affected) can show carbon fouling or oily deposits from the burning oil.

Finally, monitor your oil level meticulously. After an oil change, record the exact mileage and dipstick level. Drive normally for 500-1,000 miles, including some spirited acceleration and hard braking. Check the oil level again on level ground. If you've lost a significant amount (e.g., 1/2 quart or more) with no external leaks, the PCV system is the prime suspect.

Step-by-Step Fix

The most effective permanent fix, as validated by owners, is to replace the problematic OEM plastic valve covers with an upgraded design that relocates the PCV intake port. Here is a step-by-step guide based on the successful solution shared in the community.

1. Gather Parts and Prepare: Secure a set of aftermarket valve covers designed for this purpose, such as the Voodoo valve covers mentioned by owners, along with new gaskets and grommets. Ensure you have a torque wrench that reads in inch-pounds (in-lbs). Let the engine cool completely. Disconnect the negative battery terminal for safety.

2. Remove Engine Covers and Components: Remove any cosmetic engine covers. Then, carefully disconnect the PCV hose from the valve cover. You will need to remove components that obstruct access. This typically includes the ignition coils. Label each coil's position with tape, then unplug their electrical connectors and remove the mounting bolts to lift them out.

3. Remove the Old Valve Covers: Working on one side at a time to avoid mixing parts, unbolt the valve cover. There are usually 11-13 bolts per side. The pattern is often a 10mm socket. Loosen them in a criss-cross pattern and remove them. Gently pry the cover loose. It may be sealed tightly; use a plastic trim tool to avoid damaging the sealing surface. As one owner shared, "The coil covers are just an aftermarket dress up thing," clarifying that the real upgrade is beneath them.

4. Clean and Prepare Surfaces: This is a crucial step. Carefully scrape off all old gasket material from both the cylinder head surface and the old valve cover using a plastic gasket scraper. Clean both surfaces thoroughly with brake cleaner and lint-free rags until they are spotless. Any debris left behind will cause a leak.

5. Install New Valve Covers and Gaskets: Place the new gasket into the channel on your new valve cover. Many gaskets are rubber and do not require sealant. Some people use a tiny dab of RTV sealant at the front corners where the head meets the timing cover, but only if the manufacturer specifies. Carefully lower the new cover onto the head. As one owner confirmed, the benefit is clear: "Voodoo valve covers move the intake port to the side of the baffle so it’s a noticeable improvement."

6. Torque Bolts and Reassemble: Hand-thread all bolts to ensure they are not cross-threaded. Using your torque wrench, tighten the bolts in the proper sequence (usually starting from the center and working outwards) to the manufacturer's specification. This is often very light, typically between 8-10 ft-lbs (96-120 in-lbs). Overtorquing will crack plastic covers or warp metal ones. Reinstall the ignition coils in their correct positions and reconnect all electrical plugs and the PCV hose.

7. Final Steps and Check: Reconnect the battery terminal. Before starting, double-check that all tools are clear and all connections are secure. Start the engine and let it idle. Listen for any unusual noises and visually inspect around the new valve covers for any immediate leaks. Allow the engine to reach operating temperature and check again.

Parts and Tools Needed

• Primary Part: Aftermarket Valve Covers (e.g., Voodoo or equivalent brand that relocates PCV port). Must be compatible with the 2020 Mustang's 5.0L Coyote V8.
• Consumables: New Valve Cover Gasket Set (includes both left and right gaskets and usually the spark plug well seals). New PCV Valve (while you're in there, it's cheap preventative maintenance). PCV hose (inspect and replace if cracked or swollen).
• Basic Tools: Socket set (8mm, 10mm, 13mm are common), ratchet, extensions, and a universal joint. Torque wrench capable of low ft-lb/in-lb readings. Plastic trim tools or gasket scraper.
• Safety & Cleaning: Mechanic's gloves, safety glasses, brake cleaner, lint-free shop towels.
• Optional but Helpful: Magnetic tray for bolts, label maker or tape for coil wires, flashlight.

Real Owner Costs

The cost to fix this issue varies significantly between a DIY repair and taking it to a professional mechanic, largely due to the price of the upgraded parts.

DIY Repair Cost: The main expense is the aftermarket valve covers. A set of quality aluminum valve covers like the Voodoo brand can range from $400 to $800. A full gasket and seal kit will add $50 to $100. A new PCV valve is about $20. If you need to buy a torque wrench, add $50-100. For a DIYer who shops carefully, the total parts cost can be between $500 and $1,000. Your labor is free. As an owner comparing part prices noted on a different repair, "they have two separate ones... the other with solid rotors that’s $100 cheaper," highlighting the importance of comparing options within your budget.

Professional Repair Cost: At a shop, you must factor in the parts markup and labor. The same set of valve covers may be billed at retail price. Labor for this job is substantial, as it involves significant disassembly and precise reassembly. Expect 3-5 hours of labor at shop rates of $100-$150 per hour. Therefore, a professional repair using upgraded parts can easily total $1,500 to $2,500+, depending on the parts chosen and the shop's labor rate.

Cost of Ignoring It: Doing nothing has its own cost. Excessive oil consumption means buying more oil between changes. The varnish buildup can eventually lead to needing a costly walnut blasting service to clean the intake valves, which can run $500-$800. Severe cases could contribute to premature spark plug or oxygen sensor failure.

Prevention

Once the upgraded valve covers are installed, the primary cause is addressed. However, a few maintenance habits can ensure the PCV system operates cleanly and efficiently long-term.

First, consider adding an oil catch can in the PCV line. This is a highly recommended companion mod. As an owner succinctly put it, "Catch can and voodoo valve covers will minimize oil consumption." A catch can intercepts the oil vapor before it reaches the intake, collecting it in a reservoir you can periodically empty. This keeps your intake tract clean and is especially beneficial for performance-driven driving.

Second, adhere to a strict oil change schedule using the correct weight and quality of oil recommended for your Mustang. Fresh oil produces fewer harmful vapors. Regularly inspect the PCV valve and hose every other oil change for cracks or blockages and replace them as a maintenance item every 50,000 miles or so. Finally, if you track your car or drive very aggressively, make checking and emptying the catch can a routine part of your post-event checks.

What Owners Say

Real experiences from FORD owners:

Success Stories

"The biggest problem was trying to install the passenger side valve actuator motor. Everywhere I’ve read and the Borla instructions say to line the valve up in the open position, which worked fine for the driver side, but the passenger side only lines up with the actuator and spring in the closed valve position." — chrissdiiaz (source)

"Everywhere I’ve read and the Borla instructions say to line the valve up in the open position, which worked fine for the driver side, but the passenger side only lines up with the actuator and spring in the closed valve position." — chrissdiiaz (source)

Owner Experiences

"Never owned a 24 GT with active valve exhaust and a manual transmission. I drive him every single day." — snickerdoodle4u (source)

"The best way to tell what is going on would be to drop the oil pan and take a look. The long tube headers are a nice addition for a 4v and I wouldn't be surprised if it was previously supercharged or had nitrous." — RevolutionarySeat134 (source)

"The long tube headers are a nice addition for a 4v and I wouldn't be surprised if it was previously supercharged or had nitrous. The coil covers are just an aftermarket dress up thing." — RevolutionarySeat134 (source)

Lessons Learned

⚠️ "I still don’t know much about cars tho lol, but learning as I go. I was told to watch out for timing chain issues and was told rough idling/buzzing on cold start and idling at stops it will buzz as well." — Particular_Lead9272 (source)

⚠️ "I was told to watch out for timing chain issues and was told rough idling/buzzing on cold start and idling at stops it will buzz as well. It’s also stalled once while slowing down at a red light and also at a complete stop at a stop sign." — Particular_Lead9272 (source)

Real Repair Costs

"So I was planning on buying some suspension components for my 3 valve but I think it needs new brakes. I already have 19 inch wheels so I figured it’s time to upgrade to a four piston brake kit but they have two separate ones, a drilled and slotted 4 piston kit and the other with solid rotors that’s $100 cheaper." — Aggravating_Cost6908 (source)

"I already have 19 inch wheels so I figured it’s time to upgrade to a four piston brake kit but they have two separate ones, a drilled and slotted 4 piston kit and the other with solid rotors that’s $100 cheaper." — Aggravating_Cost6908 (source)

"03 Cobra 49,000 Miles $22,000 Stock eaton 2.7 Metco pulley" — hfdfghhbg (source)

FAQ

Q: How long does it take to replace the valve covers? A: For a competent DIY mechanic with all the right tools, plan for a full afternoon—about 4 to 6 hours. This includes time for careful disassembly, thorough cleaning of gasket surfaces (which is critical), and meticulous reassembly and torqueing. A professional shop will typically book 3-5 hours of labor for the job.

Q: Can I drive my Mustang with this oil consumption issue? A: You can drive it, but you should address it soon. Driving with it leads to gradual but certain buildup inside your intake and on valves, which can reduce performance and fuel economy over time. The most important thing is to check your oil level frequently—every other fuel stop is not unreasonable—and top it off to prevent the engine from running low on oil, which can cause severe damage.

Q: Is this a common issue on the 2020 Mustang GT? A: Based on owner discussions, it is a recognized characteristic, particularly among owners who drive their cars hard or are attentive to oil consumption. The discussion around the OEM valve cover design and the recommended upgrades (Voodoo covers, catch cans) is prevalent in the Mustang community for the 5.0L Coyote engine, which includes the 2020 model year.

Q: Should I attempt this as a DIY project or take it to a mechanic? A: This is an intermediate-level DIY job. If you have experience with basic engine work (like changing spark plugs or coils), follow instructions meticulously, and own or can borrow a torque wrench, you can successfully do it. The risk lies in damaging the new covers by over-torquing, getting debris into the engine, or creating an oil leak with a poorly installed gasket. If any of those steps make you uncomfortable, paying a reputable performance shop is a wise investment.

Q: Will a catch can alone fix the problem? A: A catch can is an excellent mitigation device and will protect your intake from oil buildup, but it does not address the root cause. The OEM valve covers will still be pulling oil into the PCV line under hard driving; the catch can just catches it. For a complete solution, the upgraded valve covers are recommended, with a catch can serving as an extra layer of protection.

Q: Do I need to tune the engine after installing new valve covers? A: No. Replacing the valve covers with a functionally identical set that simply has a better-baffled PCV port does not alter airflow, compression, or any parameter that would require an engine control module (ECM) recalibration. It is a purely mechanical improvement to the engine's breathing system.