2020 Corvette Cylinder Head Issues? Here's How to Diagnose and Fix It

How to Fix Heads Issue

Dealing with cylinder head issues on your 2020 Chevrolet Corvette can be frustrating. From unusual noises to performance problems, addressing these issues promptly is crucial. As one owner put it, "I took them to a shop and had em 'gone over' when he put my BTR springs in. I got a little frisky and lifted one (even with ARP studs) - blew out both frost plugs." It's important to understand the symptoms, potential causes, and how to address them.

Symptoms

Recognizing the symptoms of cylinder head issues early can save you from more extensive and costly repairs down the line. Owners have reported several symptoms related to cylinder heads that can impact the vehicle's performance and reliability.

One common symptom is a noticeable decrease in engine performance. This can manifest as reduced power, slower acceleration, or a general feeling that the engine is not running as smoothly as it should. You might notice this especially when trying to accelerate quickly or climb hills.

Another symptom to watch out for is unusual engine noises. These noises can range from ticking or clicking sounds to more pronounced knocking or tapping. These noises often become more noticeable at idle or during initial acceleration. Pay attention to whether the noise changes with engine speed, as this can provide clues to the underlying problem.

Surface rust and distress can be an indicator. It's important to address rust before it causes more significant damage. Examine visible parts of the engine and cylinder heads for any signs of rust or corrosion, which can indicate potential issues.

Finally, issues with the cooling system can often be traced back to cylinder head problems. If you notice that your vehicle is overheating frequently, or if you are constantly having to add coolant, there may be a leak or other issue related to the cylinder heads. Leaks can occur due to damaged gaskets or cracks in the cylinder head itself.

Most Likely Cause

Based on owner reports, the most likely cause of cylinder head issues in the 2020 Chevrolet Corvette is related to the cylinder head cores themselves, or issues stemming from modifications done to the heads. Cylinder head cores are the foundation of the cylinder head, and any defects or damage can lead to various problems. Over time, these cores can develop cracks, warping, or other structural issues due to heat, pressure, and general wear and tear. Additionally, improper installation or maintenance can exacerbate these problems.

One owner shared an experience highlighting the importance of proper frost plug installation: "I got a little frisky and lifted one (even with ARP studs) - blew out both frost plugs (if you ever have to change them make SURE you use the metric size - not generic 1-1/4")." This illustrates how seemingly minor components can have a significant impact on the cylinder head's overall performance.

How to Diagnose

Diagnosing cylinder head issues requires a systematic approach to pinpoint the exact cause of the problem. Begin with a visual inspection, followed by more in-depth tests.

1. Visual Inspection: Start by visually inspecting the cylinder heads for any obvious signs of damage, such as cracks, leaks, or corrosion. Pay close attention to the areas around the head gasket, valve covers, and exhaust manifolds. Look for any signs of coolant or oil leaks.
2. Compression Test: A compression test can help you determine if there is a loss of compression in one or more cylinders, which could indicate a problem with the cylinder heads. To perform a compression test, you'll need a compression tester. Remove the spark plugs and insert the tester into each cylinder one at a time. Crank the engine and record the compression reading for each cylinder. Compare the readings to the manufacturer's specifications.
3. Leak-Down Test: A leak-down test can help you identify the source of compression loss. This test involves injecting compressed air into each cylinder and listening for air escaping from the exhaust, intake, or cooling system. This test requires a leak-down tester and an air compressor.
4. Cooling System Pressure Test: A cooling system pressure test can help you identify leaks in the cooling system, which may be related to cylinder head issues. This test involves pressurizing the cooling system and looking for any signs of leaks.
5. Check for Coolant in Oil: Examine the engine oil for any signs of coolant contamination. Coolant in the oil can indicate a leaking head gasket or a cracked cylinder head. The oil will often have a milky or frothy appearance.

Tools Required:

• Compression tester
• Leak-down tester
• Cooling system pressure tester
• Socket set
• Wrench set
• Inspection light

Step-by-Step Fix

Addressing cylinder head issues can range from simple repairs to complete cylinder head replacements, depending on the severity of the problem. Here are the general steps you can take:

1. Gather Information: Collect all relevant information, including any diagnostic codes, symptoms, and previous repairs.
2. Prepare the Vehicle: Disconnect the battery and allow the engine to cool completely. Drain the coolant and oil. Remove any components that may obstruct access to the cylinder heads, such as the intake manifold, exhaust manifolds, and valve covers.
3. Remove Cylinder Heads: Carefully remove the cylinder heads, following the manufacturer's instructions. Be sure to label and organize all components to ensure proper reassembly.
4. Inspect Cylinder Heads: Thoroughly inspect the cylinder heads for any signs of damage, such as cracks, warping, or corrosion. Check the valve guides, valve seats, and valve springs for wear or damage.
5. Clean Cylinder Heads: Clean the cylinder heads thoroughly to remove any carbon deposits, oil, or other contaminants. Use a solvent or parts cleaner and a brush to clean all surfaces.
6. Repair or Replace Cylinder Heads: Depending on the extent of the damage, you may be able to repair the cylinder heads. If the damage is too severe, you may need to replace the cylinder heads.
7. Install New Gaskets and Seals: Always use new gaskets and seals when reinstalling the cylinder heads. This will ensure a proper seal and prevent leaks.
8. Reinstall Cylinder Heads: Carefully reinstall the cylinder heads, following the manufacturer's instructions. Torque the cylinder head bolts to the specified torque in the correct sequence.
9. Reassemble Components: Reinstall all of the components that you removed earlier, such as the intake manifold, exhaust manifolds, and valve covers.
10. Refill Fluids: Refill the coolant and oil to the proper levels.
11. Test the Vehicle: Start the engine and let it run for a few minutes. Check for any leaks or unusual noises. Take the vehicle for a test drive to ensure that the problem has been resolved.

As one owner shared: "Replaced with a new hose and ABA SS hose clamps instead of the springs. I have had to replace a couple of coolant spring clamps in the past several years." (source) This shows the importance of using quality replacement parts.

Parts and Tools Needed

• Cylinder head gaskets
• Cylinder head bolts
• Valve cover gaskets
• Intake manifold gaskets
• Exhaust manifold gaskets
• Valve stem seals
• Cylinder heads (if replacement is necessary)
• Coolant
• Oil
• Socket set
• Wrench set
• Torque wrench
• Cleaning solvents

Real Owner Costs

The cost of addressing cylinder head issues on your truck can vary widely depending on the severity of the problem and whether you choose to do the repairs yourself or take it to a shop.

DIY Repair:

• Cylinder head gaskets: $50 - $150
• Cylinder head bolts: $30 - $80
• Valve cover gaskets: $20 - $50
• Intake manifold gaskets: $20 - $50
• Exhaust manifold gaskets: $30 - $70
• Valve stem seals: $10 - $30
• Coolant: $20 - $40
• Oil: $30 - $60

Total DIY Cost: $210 - $530 (excluding cylinder head replacement)

Professional Repair:

• Labor: $500 - $1500+ (depending on the complexity of the repair)
• Parts: Same as DIY costs, but often marked up by the shop
• Cylinder head replacement (if necessary): $500 - $2000+ per head

Total Professional Cost: $710 - $4030+ (depending on the extent of the damage and whether cylinder head replacement is required)

Prevention

Preventing cylinder head issues involves proactive maintenance and careful attention to the vehicle's operating conditions.

• Regular Maintenance: Adhere to the manufacturer's recommended maintenance schedule, including oil changes, coolant flushes, and spark plug replacements.
• Monitor Engine Temperature: Keep a close eye on the engine temperature gauge and address any overheating issues immediately. Overheating can cause significant damage to the cylinder heads.
• Use Quality Fluids: Use high-quality coolant and oil that meet the manufacturer's specifications.
• Avoid Overloading the Engine: Avoid putting excessive strain on the engine, such as towing heavy loads or driving at high speeds for extended periods.
• Inspect Regularly: Regularly inspect the engine and cooling system for any signs of leaks or damage. Address any issues promptly before they escalate into more significant problems. As another owner mentioned, "You might want to check with Tony, tell him your plan and see if he'll work with you if you throw a set of heads/headers on later." (source) This highlights the importance of planning and consultation when considering modifications.

What Owners Say

Real experiences from CHEVROLET owners:

Success Stories

"Quote: Originally Posted by RB211 Finally fixed my power steering leak! Damned little hose between the reservoir and the pump (or it's spring clamps) was bad." — grinder11 (source)

Owner Experiences

"If you're running bronze guides with stock rockers, with a .600ish" lift, 225° duration cam, expect valve guide life of 20,000-30,000 miles tops. I've been there-done that." — American Heritage (30,000 miles) (source)

"Quote: Originally Posted by grinder11 Stock rockers are fine if you're running PM guides, and don't put a ton of miles on you're car. If you're running bronze guides with stock rockers, with a .600ish" lift, 225° duration cam, expect valve guide life of 20,000-30,000 miles tops." — American Heritage (30,000 miles) (source)

"Replaced with a new hose and ABA SS hose clamps instead of the springs. I have had to replace a couple of coolant spring clamps in the past several years." — grinder11 (source)

Lessons Learned

⚠️ "The new one has a 3.9" hole vs the 4.1" on the LS9. I'll be a bit more careful with my right foot till the tune is done and I can be trusted with the power." — JumboShrimp (source)

Pro Tips from Owners

💡 "Personally, I think you should do it all at once and avoid the tune fee repetition cost. You might want to check with Tony, tell him your plan and see if he'll work with you if you throw a set of heads/headers on later." — Midwayman (source)

💡 "I took them to a shop and had em 'gone over' when he put my BTR springs in. I got a little frisky and lifted one (even with ARP studs) - blew out both frost plugs (if you ever have to change them make SURE you use the metric size - not generic 1-1/4")." — JumboShrimp (source)

FAQ

Q: How long does it take to fix cylinder head issues?

A: The time required to fix cylinder head issues can vary depending on the extent of the damage and whether you choose to do the repairs yourself or take it to a shop. Simple repairs, such as replacing gaskets or seals, may only take a few hours. More complex repairs, such as cylinder head replacement, can take several days.

Q: Can I drive with cylinder head issues?

A: Driving with cylinder head issues is generally not recommended. Continuing to drive with these problems can cause further damage to the engine and potentially lead to more costly repairs. If you suspect that you have cylinder head issues, it's best to have the vehicle inspected by a qualified mechanic as soon as possible.

Q: Is this a common issue on the 2020 Chevrolet Corvette?

A: While cylinder head issues can occur on any vehicle, they are not necessarily a common problem on the 2020 Chevrolet Corvette. The frequency of these issues can depend on factors such as maintenance habits, driving conditions, and the overall condition of the vehicle.

Q: DIY vs mechanic - what's recommended?

A: Whether you should attempt to fix cylinder head issues yourself or take the vehicle to a mechanic depends on your mechanical skills, experience, and the complexity of the repair. If you are comfortable working on engines and have the necessary tools, you may be able to handle some of the simpler repairs yourself. However, for more complex repairs, such as cylinder head replacement, it's best to leave it to a qualified mechanic. As one owner stated, "Personally, I think you should do it all at once and avoid the tune fee repetition cost. You might want to check with Tony, tell him your plan and see if he'll work with you if you throw a set of heads/headers on later." (source) Showing that modifications may be best left to the experts.