Description
Product Overview
The ACDelco Manual Timing B Idler (model T42024) is engineered to deliver precise engine timing for a wide range of General Motors vehicles. Crafted from high‑strength steel, this idler offers exceptional durability and resistance to wear, ensuring consistent performance over the life of the engine. With dimensions of 5.2 x 5.2 x 1.5 inches and a weight of 15.2 ounces, it fits seamlessly into the original timing system, meeting or exceeding OEM specifications. The part carries the manufacturer number 89049140 and is compatible with the ACDelco Gold and Professional lineups, guaranteeing a perfect match for both original and replacement applications.
Usage
Designed for use in both repair shops and home garages, the Timing B Idler is ideal for engine rebuilds, timing chain replacements, and routine maintenance on GM powertrains. Its robust construction tolerates high‑temperature environments and the stresses of high‑rpm operation, making it suitable for daily drivers, performance builds, and fleet vehicles alike. Installers will appreciate the straightforward bolt‑on design that aligns with factory service procedures, reducing installation time and minimizing the risk of errors.

Why Choose Us
ACDelco is a trusted name in automotive parts, known for rigorous testing and adherence to original equipment standards. This Timing B Idler is manufactured to exacting tolerances, ensuring a perfect fit and reliable function. As a premium aftermarket component, it offers the same quality as OEM parts at a more accessible price point. Each unit undergoes comprehensive quality checks, and the product is backed by ACDelco’s reputation for durability and performance, giving you confidence in every installation.
Key Features
- High‑strength steel construction for long‑lasting durability
- Exact OEM dimensions and fit for seamless integration
- Designed for GM engine families, covering a broad model range
- Easy bolt‑on installation reduces labor time
- Backed by ACDelco’s quality assurance and warranty support
FAQ
Is this idler compatible with all GM engines?
The Timing B Idler (T42024) fits a wide variety of GM engines that use the Manual Timing B system. Refer to your vehicle’s service manual or the fit guide on the ACDelco website to confirm compatibility.
Do I need any special tools to install the idler?
Installation requires standard hand tools such as a socket set and torque wrench. No specialized equipment is necessary beyond what is typically used for timing chain work.
What warranty does ACDelco provide for this part?
ACDelco offers a limited warranty that covers defects in material and workmanship. Specific terms vary by region, so check the warranty card included with the product for details.
Can I use this part as a direct replacement for the original OEM idler?
Yes, the Timing B Idler is manufactured to meet or exceed OEM specifications, making it a direct, drop‑in replacement for the original part.
How does the steel material benefit the idler’s performance?
Steel provides superior strength and heat resistance, ensuring the idler maintains its shape and function under the high stresses and temperatures typical of engine operation.





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