Guide to Engine Cylinder Head Bolts for the 1973-2004 Chrysler 300
Find the correct head bolts by understanding the key differences between the V8 and V6 engines in this model range.
- Verify your engine: The 1973-2004 range includes a 1979 V8 model and a 1999-2004 V6 model; parts are not interchangeable.
- Always replace head bolts when changing a head gasket; they are single-use Torque-to-Yield (TTY) bolts on the 3.5L V6.
- Edelbrock bolts are for performance V8 applications and are not compatible with stock heads or the 3.5L V6 engine.
- Proper installation requires a specific multi-stage torque sequence plus an angle-of-rotation step; do not guess.
Understanding Your 1973-2004 Chrysler 300
If you own a Chrysler 300 from the 1973-2004 model years, you might have one of two very different cars. This is important because the engine parts are not interchangeable.
- 1979 Chrysler 300: This is a special one-year model based on the Chrysler Cordoba. It came with a 5.9L (360 cubic inch) V8 engine. These cars are part of the classic muscle and luxury era.
- 1999-2004 Chrysler 300M: This is a modern front-wheel-drive sedan. It was equipped with a 3.5L V6 engine. This car is part of the LH platform, which also included the Dodge Intrepid and Chrysler Concorde.
Before buying an engine cylinder head bolt set, you must know which vehicle and engine you have. A bolt set for the V8 will not work on the V6, and vice-versa.
Symptoms of Failing Head Bolts
Head bolts themselves don't show symptoms. Instead, you will see the signs of a failing head gasket, which happens when the bolts can no longer provide enough clamping force. Ignoring these signs can lead to catastrophic engine damage.
- Engine Overheating: This is a classic sign. A bad seal allows hot exhaust gases to enter the cooling system, or coolant to be lost, causing the engine to run hot.
- White Smoke from Exhaust: If you see thick, white smoke coming from the tailpipe, it's often coolant burning in the combustion chamber. This smoke may have a sweet smell.
- Milky Engine Oil: When coolant mixes with engine oil, it creates a milky, frothy substance that looks like a milkshake. You can find this on the oil dipstick or under the oil filler cap.
- Unexplained Coolant Loss: If your coolant level keeps dropping but you can't find an external leak, it might be leaking into the engine internally.
- Poor Engine Performance: A loss of compression from a bad seal can cause rough idling, engine misfires, and a noticeable loss of power.
Choosing the Right Aftermarket Head Bolts
When replacing a head gasket, you must also replace the head bolts. Most modern engines, including the 3.5L V6 in the 300M, use Torque-to-Yield (TTY) bolts.
What are TTY Bolts?
Torque-to-Yield bolts are designed to be stretched one time. During installation, they are tightened to a specific torque and then turned an additional angle (like 90 degrees). This permanently stretches the bolt to provide a very precise and even clamping force. Because they are permanently stretched, they cannot be reused. Attempting to reuse TTY bolts can lead to incorrect clamping force and another failed head gasket.
OEM vs. Aftermarket
For a stock engine repair, high-quality aftermarket TTY bolts from brands like Fel-Pro or Mahle are a reliable and cost-effective choice. They are designed to meet or exceed original equipment specifications. For the 1999-2004 300M, these brands offer complete sets that are a direct fit for the 3.5L V6.
For the 1979 V8 engine, especially if you are upgrading to aftermarket aluminum cylinder heads, you will need a specialized bolt kit. Edelbrock, for example, makes high-performance head bolt kits specifically for their cylinder heads on Chrysler small block V8s. These bolts are often made of stronger materials and are not TTY, but they are designed to work with specific performance parts and are not for stock heads.
Common Ordering Mistake
The most common mistake is ordering parts for the wrong "Chrysler 300." Verify your year and engine (5.9L V8 or 3.5L V6) before adding parts to your cart. Edelbrock head bolts are generally for older V8 engines and will not fit the 1999-2004 300M.
Known Issues, Recalls, or TSBs
While there are no specific recalls for cylinder head bolts on the 1999-2004 Chrysler 300M, some earlier versions of Chrysler's V6 engines had known issues with head gaskets. There are no widespread, major recalls related to head gasket failure on the 300M itself. Always ensure you are using new, quality head bolts and following the correct torque procedure to prevent future problems.
Cost to Replace Engine Cylinder Head Bolts
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket Head Bolt Set (3.5L V6) | $35 - $70 |
| New Aftermarket Head Bolt Set (5.9L V8 Performance) | $80 - $150 |
| Shop Labor (Head Gasket & Bolt Replacement) | $720 - $1,056 |
| Total Job Cost (Parts + Labor) | $1,582 - $1,919 |
Note: Costs are estimates and can vary based on location and specific vehicle condition. The primary cost of the job is the labor-intensive head gasket replacement.
Frequently Asked Questions
Can I reuse my old head bolts?
No. Most modern engines, including the 3.5L V6 in the 300M, use Torque-to-Yield (TTY) bolts that are designed for single use only. Reusing them is a major risk and will likely lead to another failed head gasket. Always install new bolts.
Do I need special tools to install new head bolts?
Yes. You will need a quality torque wrench and a torque-angle gauge. The bolts are tightened in multiple stages, with the final stage requiring a specific angle of rotation (e.g., 90 degrees). Guessing this angle is not acceptable and will result in improper clamping.
Why are Edelbrock head bolts more expensive?
Edelbrock head bolts are designed for high-performance applications, often for use with their aftermarket aluminum cylinder heads. They are made from higher-strength materials (like chromoly steel) and are engineered to handle the increased stresses of a modified engine. They are not necessary for a standard, stock engine repair.
Do I need to replace bolts on both cylinder heads?
Yes. If you are doing a head gasket job, it is highly recommended to service both cylinder heads at the same time, especially on a V-type engine. This means you will need two sets of head bolts (many kits are sold per head). This ensures even clamping force and reliability across the entire engine.
Technical Specifications
Bolt Type: Torque-to-Yield (TTY) for 3.5L V6, Standard Hardened for most V8 performance applications. Material: High-strength steel or chromoly for performance applications.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.