Hummer H3 Ignition Coil Guide for 2006-2010 Models
Fix your H3's rough idle and check engine light by understanding its ignition coil system.
- A bad ignition coil is a very common cause of a rough idle and check engine light on the H3.
- For I-5 engines, check cylinder #5 for water intrusion, as this is a frequent and specific failure point.
- It is strongly recommended to replace all coils at once using a quality brand like ACDelco, Delphi, or NGK.
- This is a simple DIY job that most owners can complete in under an hour with basic tools.
Is Your H3 Shaking, Sputtering, or Losing Power?
A bad ignition coil is a very common problem on the Hummer H3. When a coil fails, the engine cylinder it's connected to can't fire properly. This is called a misfire. You will usually feel a rough, shaky idle and notice the check engine light is on. The light may even flash, which is a sign of a serious misfire that could damage other parts like your catalytic converter.
A Common Problem for H3 Inline-5 Engines
The inline-5 engine (3.5L and 3.7L) has a specific design flaw. Water can run down the engine and collect in the spark plug hole for the cylinder closest to the driver (Cylinder #5). This water causes the ignition coil and spark plug to rust and fail, leading to a P0305 error code. 🎬 Watch this video to see why Cylinder 5 often fails. When replacing this coil, make sure the area is dry and apply dielectric grease to the new coil boot to help keep moisture out.
Choosing the Right Aftermarket Ignition Coil
You don't have to buy the most expensive coil, but the cheapest ones are often a bad idea. Coils can be grouped into quality tiers. Since this is a critical part for engine performance, choosing a quality brand is important to avoid doing the job again soon.
Brand Quality Tiers
- OEM / Premium Aftermarket (Recommended): These brands are either the original supplier to Hummer or have a long reputation for quality and reliability. They are the safest bet for a long-lasting repair. Brands include ACDelco (the original GM part), Delphi, NGK, and Denso.
- Quality Mid-Range: These brands offer a good balance of price and performance. They are a solid choice if a premium brand is not in the budget. Brands like Bosch, Hitachi, and Standard Ignition (SMP) fit in this category.
- Economy Brands: This tier includes brands like DriveWire, True Tech, and other lesser-known names. While the low price is tempting, their lifespan and performance can be inconsistent. They might get you out of a bind, but they are not recommended for long-term reliability.
Should I Replace All The Coils At Once?
Yes. It is highly recommended to replace all ignition coils at the same time, especially if your H3 has over 80,000 miles. The coils are all the same age and have been working under the same conditions. If one has failed, the others are likely not far behind. Replacing them all at once saves you from future breakdowns and repeated repair jobs. It's also the perfect time to install new spark plugs.
Ignition Coil Replacement Cost for Hummer H3
The cost can vary based on the brand you choose and whether you do the work yourself. The job is simple enough for most DIY mechanics.
| Part / Service | Estimated Cost |
|---|---|
| New OEM (Single ACDelco Coil) | $100 - $145 |
| New Aftermarket (Single Coil) | $37 - $120 |
| New Aftermarket (Set of 5 or 8) | $125 - $445 |
| Shop Labor | $100 - $200 |
Frequently Asked Questions
How many ignition coils does my Hummer H3 have?
If you have the 3.5L or 3.7L inline-5 engine, you have five ignition coils. If you have the 5.3L V8 engine, you have eight ignition coils.
How do I know which coil is bad?
The easiest way is to use an OBD2 scanner. It will give you a code like 'P0304', which means cylinder #4 is misfiring. If you don't have a scanner, you can swap the coil from the suspected bad cylinder with a coil from a good cylinder. For example, if you suspect cylinder 4 is bad, swap its coil with cylinder 1. If the misfire code changes to 'P0301', you know the coil is the problem.
🎬 See a step-by-step guide on diagnosing a bad coil.Is it hard to replace the ignition coils myself?
No, this is a very DIY-friendly job. You only need basic tools like a 10mm socket and a screwdriver. You will need to remove the plastic air intake that sits on top of the engine to get access, but this is only held on by a few bolts and clamps. The entire job for all coils can usually be done in under an hour.
🎬 Watch this super-easy walkthrough to replace your coil packs.Were there any recalls on H3 ignition coils?
No. There have been no safety recalls issued for the ignition coils on the 2006-2010 Hummer H3. Recalls were issued for other parts, like the HVAC blower motor and hood louver, but not the coils.
Helpful Videos
Technical Specifications
OEM Part Numbers: 12570616 12611424 19300921 UF303 UF413
This vehicle uses a Coil-on-Plug (COP) ignition system. The 3.5L/3.7L I5 engines require 5 coils. The 5.3L V8 engine requires 8 coils.
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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.
- Hummer H3:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is Your H3 Shaking, Sputtering, or Losing Power?
- A Common Problem for H3 Inline-5 Engines
- Choosing the Right Aftermarket Ignition Coil
- Brand Quality Tiers
- Should I Replace All The Coils At Once?
- Ignition Coil Replacement Cost for Hummer H3
- Frequently Asked Questions
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