Bosch Double Iridium 0242129529 double iridium spark plug (1 pack) for gasoline engines
Product description
The essentials
If you’re keeping a petrol car running reliably, a spark plug is one of those small parts that can make a noticeable difference. The Bosch Double Iridium 0242129529 is a single iridium spark plug aimed at dependable ignition and long service life, using iridium at the centre electrode and a matching design on the ground side.
On paper, this is the sort of replacement you’d choose when you want smoother running and better wear resistance rather than a basic plug that you might replace more often. It also comes with the kind of “fitting guidance” you actually need for the job: the electrode gap is pre-set, and the instructions advise against lubricating the thread.
That said, it’s not a universal part. Spark plug design is engine-specific, so getting the right fit matters more than chasing material names.
What to know before buying
Bosch stresses compatibility via your vehicle’s parts search, and that’s the safest way to approach this plug. The engine requirements determine the plug design needed for each car, so relying only on general “it’s for petrol” matching can be a mistake.
You’ll also want to treat this as an install-with-care item. The thread lubrication advice and the prescribed tightening torque aren’t there for decoration—skip them and you risk creating problems during fitting or performance down the line.
Here’s a practical micro-scenario: you’ve booked a service day, removed an old plug, and you’re ready to swap it. Before you drop the new Bosch in, you check the specification your engine needs, ensure the gap is already pre-set (so there’s no “gap adjusting” job), and then tighten with a torque wrench rather than guessing.
Key features that affect everyday driving
The main idea behind the Double Iridium design is improved wear resistance and smoother running. Iridium at the centre and ground electrodes is intended to support stable ignition over time, which can matter if your car sees mixed driving—commutes, short trips, and longer runs.
Another reassuring point for DIY or careful installers is that it’s described as easy to replace: no adjustment is necessary because the electrode gap is pre-set. If you’ve ever dealt with plugs that need measuring and tweaking, this “set-and-fit” approach can feel like less hassle.
Still, keep expectations realistic: better materials can help, but a spark plug won’t compensate for bigger ignition issues in the engine (for example, if other parts are worn or the ignition system has faults).
Tech specs (from the product information)
- Electrode gap: 1.1 mm
- Thread length and size: 26.5 mm, M 12 x 1.25
- Spark position: 5 mm
- Prescribed tightening torque: 23 Nm
Pros and potential limitations
Why it tends to make sense - Iridium construction is designed for smoother running and higher wear resistance. - Pre-set electrode gap means you don’t have to adjust it. - The fitting guidance (avoid lubricating the thread, use a torque wrench) helps reduce common installation errors.
Where you need to be cautious - It’s only the right choice if it matches your engine’s requirements, compatibility isn’t optional. - There’s no indication here of fitment for every petrol engine, so “works for petrol” isn’t enough. - If you’re expecting a dramatic transformation from a worn-out ignition system overall, it may stay within its true role: replacing a component, not fixing unrelated faults.
Who it suits (and who should skip it)
It’s a good fit if you’re replacing a worn or due spark plug with an iridium plug that’s set up for reliable ignition and longer service life, and you’re happy to follow the install guidance carefully.
It may not suit you if you’re buying without confirming the correct part for your specific engine, or if you’re the type of installer who prefers “hand-tight and hope” rather than using the specified torque.
Worth considering if you want to keep maintenance straightforward—especially because the electrode gap is pre-set—just don’t ignore the parts search and your engine requirements.
Should you buy it?
Buy it when your vehicle’s engine requirements match the Bosch Double Iridium 0242129529 specification, and you’re aiming for dependable petrol ignition with a focus on wear resistance.
Skip it if you can’t confirm compatibility using the parts search for your vehicle, or if you can’t follow the recommended tightening approach (torque wrench use) and the advice not to lubricate the thread.
This is the kind of plug that makes sense for drivers who care about getting the right part first time and installing it properly, rather than treating spark plugs as interchangeable.
Mini FAQ
FAQs
Is this spark plug adjustable?
No adjustment is described as necessary because the electrode gap is pre-set.
Do I need to lubricate the thread before fitting?
The information provided advises not to lubricate the thread.
What torque should be used when installing?
The prescribed tightening torque listed is 23 Nm.
How do I make sure it’s compatible with my car?
Bosch highlights using the parts search function to find the correct spark plug for your vehicle, as the engine requirements define the required design.
What if I’m unsure about the product details?
The listing suggests using amazon Customer Questions and Answers to reach out and get further information.