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Engine Timing Cover
This photo shows the same type of part you'll receive. Since each used part has its own wear and scratches, yours may look slightly different. Check the product notes for details about the condition of this specific part.

2003 - 2004 Chevrolet Trailblazer Timing Cover (OEM)

Only 1 left in stock
$79.95

ℹ️ Product Notes

This is a used Timing Cover. It is sold as an assembly. It fits vehicles with 4.8L, 5.3L, 5.7L, or 6.0L engines.

Fits V8 engines only. This cover does not have a hole for a cam sensor. Check your old cover to make sure it matches before buying.
Condition: Excellent (A)
Like new, minimal to no wear
See Other Chevrolet Trailblazer Engine Timing Covers
SKU #
7258122-86400-803

Why Buy Used OEM Parts?

✓ Quality-Verified: Every used OEM part we sell has been professionally inspected and tested to ensure it meets our quality standards. While it may show some cosmetic wear from previous use, it's fully functional and ready to install.

✓ Original Equipment: This is a genuine OEM (Original Equipment Manufacturer) part - the exact same part that came with your vehicle from the factory. It's designed specifically for your make and model, ensuring perfect fitment and performance.

✓ Works Like New: Despite some visual wear, this part will perform just as well as a brand new one. The internal components and functionality are intact, giving you the same reliability you'd expect from OEM quality.

✓ Significant Savings: Save 50-80% compared to buying new! Used OEM parts offer exceptional value - you get factory quality at a fraction of the cost. It's the smart choice for budget-conscious vehicle owners who won't compromise on quality.

✓ Risk-Free Purchase: We stand behind our used parts with a generous 6-month warranty, 30-day returns, and 100% money-back guarantee. If it doesn't work out for any reason, simply return it for a full refund. You have nothing to lose!

🛡️ 30-Day Returns + 6-Month Warranty - Buy with Confidence!

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Vehicle Fitment Guide

This part fits the following vehicles:

Fitment information is being updated. Please contact us to verify compatibility.

Policies

Shipping & Handling

  • Standard shipping: 3-7 business days via UPS Ground
  • Parts are carefully packaged to prevent damage during transit

Returns (30 Days)

We accept returns within 30 days of delivery for this part.

  • Defective parts: We will replace the part or issue a refund at our discretion
  • Electronic parts: Must be returned with the sealed inspection bag unopened. The clear bag allows full visual inspection before opening. Once opened, electronic parts can only be exchanged for a replacement if defective — no refunds
  • Programming: "Needs to be programmed to my vehicle" is not a valid return reason. Many modules require dealer programming — we're happy to help connect you with resources if your dealer says it's not programmable
  • Return shipping: We cover return shipping as part of our 100% money-back guarantee
  • Parts must be returned in original packaging and unmodified condition
  • Poorly packaged returns that arrive damaged will not be credited

6-Month Warranty

All used parts include a 6-month warranty from the date of purchase.

  • If your part fails within 6 months, we will send a replacement
  • Refunds are only issued if we cannot provide a suitable replacement
  • Warranty covers defects — not installation errors, misuse, or damage after installation

Note: Warranty is for replacement, not refund. A part failing on day 80? We'll replace it. But the return window for refunds is 30 days.

Damaged in Shipping?

If your part arrives damaged:

  • Stop immediately — do not install the part
  • Keep all original packaging and boxes
  • Take clear photos of the damage and packaging
  • Contact us within 48 hours of delivery

We will handle the carrier claim. You are not responsible for shipping damage — we just need your help documenting it.

Order Cancellation

Orders can be cancelled before shipment for a full refund. Once shipped, cancellations follow our return policy.

Symptoms & Diagnosis

Warning Signs of a Failing Timing Cover:

  • Oil leaks near the front of the engine.
  • Engine overheating.
  • Low oil pressure.
  • Unusual noises coming from the engine, like rattling or ticking.
  • Visible cracks or damage to the timing cover.

Testing the Timing Cover:

  1. Visual Inspection: Carefully check the timing cover for cracks, leaks, or damage.
  2. Oil Leak Check: Look for oil pooling around the timing cover and the surrounding engine area. Clean the area and monitor for new leaks.
  3. Pressure Test: A mechanic can perform a pressure test to check for leaks in the cooling system, which could indicate a problem with the timing cover's seal.

Common Failure Causes:

  • Age and wear: Over time, the timing cover can become brittle and crack.
  • Extreme temperatures: Repeated exposure to high and low temperatures can weaken the material.
  • Improper installation: Incorrect installation can damage the timing cover or its seals.
  • Damaged seals or gaskets: Seals and gaskets can dry out and crack, leading to leaks.
  • Impact damage: Road debris or accidents can cause physical damage to the timing cover.

Buyer's Checklist

What to Look For:

  • Check for cracks, damage, or repairs.
  • Inspect the gasket surface for flatness and smoothness.
  • Make sure all mounting points are intact.
  • Confirm the part is compatible with your specific engine.

Quality Indicators:

FeatureUsed OEMRefurbished OEMNew Aftermarket
MaterialOriginal factory materialOriginal factory materialMaterial meeting OE specifications
ConditionInspected for cracks and damageProfessionally restoredBrand new
TestingTested for leaks and proper functionTested for leaks and proper functionMeets OE specifications
WarrantyVaries by sellerVaries by sellerVaries by seller

What's Typically Included:

  • Timing cover.
  • Sometimes includes a new gasket or seal.
  • Mounting bolts may or may not be included.

Installation Overview

Difficulty Level and Estimated Time:

  • Difficulty: Medium to High.
  • Estimated Time: 4-8 hours.

Special Tools Needed:

  • Socket set.
  • Wrench set.
  • Torque wrench.
  • Harmonic balancer puller (may be required).
  • Jack and jack stands.
  • Engine support bar (recommended).

Critical Steps and Tips:

  1. Disconnect the battery: This is a crucial safety step.
  2. Drain the coolant and oil: Prevent spills and contamination.
  3. Remove accessories: Remove belts, pulleys, and other components attached to the timing cover.
  4. Remove the harmonic balancer: Use the correct puller tool to avoid damage.
  5. Clean the mating surfaces: Ensure a proper seal with the new timing cover.
  6. Install the new timing cover: Use a new gasket and torque bolts to the correct specification.
  7. Reinstall all components: Double-check all connections.
  8. Refill fluids: Add coolant and oil to the correct levels.

DIY or Professional Installation:

  • Due to the complexity and potential for engine damage, professional installation is recommended if you are not experienced with engine repair.

Buying Options

Compare:

| Feature | Used OEM equipped with a

Used OEM: Best value - genuine factory parts, tested and inspected, at significantly lower prices. Refurbished OEM: Factory parts professionally restored with new components. New Aftermarket: Brand new third-party parts built to OE specs.

Typical Lifespan

  • The typical lifespan of a timing cover is 100,000-150,000 miles or 7-10 years.

Factors Affecting Longevity:

  • Regular maintenance.
  • Driving conditions (extreme heat or cold).
  • Quality of replacement parts.
  • Engine oil quality and change intervals.
  • Coolant type and condition.

Price Ranges

  • Used OEM: $50 - $150
  • Refurbished OEM: $100 - $250
  • New Aftermarket: $80 - $200
  • Labor Cost: $300 - $800
  • Total Job Cost: $350 - $1000

Vehicle-Specific Notes

  • Some models are known to have issues with the timing cover warping over time, leading to oil leaks.
  • Check for any Technical Service Bulletins (TSBs) related to timing cover leaks or failures for your specific vehicle model and year.
  • Some owners have reported issues with the oil cooler lines leaking near the timing cover.

Verification After Install

  • Check for any oil or coolant leaks around the timing cover.
  • Monitor the engine temperature to ensure it is running within the normal range.
  • Listen for any unusual noises coming from the engine.
  • Check the oil pressure gauge to ensure it is reading within the normal range.
  • After a short drive, re-inspect the area for any signs of leaks.

FAQ

Q: How do I know if my timing cover is leaking?
A: Look for oil leaks near the front of the engine. You may also notice a burning oil smell.

Q: Can I drive with a leaking timing cover?
A: It's not recommended. A leaking timing cover can lead to low oil pressure, engine overheating, and eventually, engine damage.

Q: Is it difficult to replace a timing cover myself?
A: It can be a complex job, requiring specialized tools and knowledge of engine mechanics. Professional installation is often recommended.

Q: What happens if the timing cover fails completely?
A: A complete failure can lead to significant oil leaks, engine overheating, and potentially catastrophic engine damage.

Q: What is the purpose of the timing cover?
A: The timing cover protects the timing chain or belt and helps maintain proper engine timing. It also helps prevent oil leaks and keeps debris out of the engine.

Part Specifications

OEM Part Numbers:

  • Cadillac: 12561243
  • GM: 12633904, 12633906
  • Isuzu: 8125612430

Fits Years: 2003 2004

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