When I was an apprentice mechanic, replacing starter motors was a regular repair. In those days, accessing the starter was easy. Modern cars are not as generous but the starter motors are more durable. Here’s where I share my starter motor replacement hacks.
Replacing a car’s starter motor isn’t difficult. However, vehicles with large engines will be more challenging. The front-wheel-drive transverse powertrain layout is the most common type and generally offers better access to the starter motor, and is, therefore, easiest to replace.
In this post, you’ll learn how difficult it is to replace a starter motor on both front-wheel drive and rear-drive cars. I’ll outline the workflow, you’ll learn about the tools you’ll need and how long the whole job should take.
Starter Motor Replacement Challenges
Every car model will present particular challenges but generally, we can grade the size of the challenge by two criteria:
- How the engine is laid out in the engine bay
- How large the engine is
The first criteria – Powertrain layout (engine, transmission, and drive combined). The layout comes in two flavors – Longitudinal and Transverse.
The longitudinal layout means the engine is fitted in the engine bay, well…lengthways or front to back if you like. It’s mostly associated with rear-wheel drive and 4X4 vehicles.
The transverse layout means the engine is fitted in the engine bay width ways or left to right. It’s mostly associated with front-wheel drive or all-wheel drive vehicles.
The starter motor replacement procedure differs for both, and we’ll look at that procedure below.
The second criterion is engine size. The concept is simple, the larger the engine the more difficult the starter replacement procedure is.
It’s not unusual on larger engines to remove several other components in order to access and remove the starter motor. Some of the removed components may themselves require replacement gaskets, seals or recalibration, etc. These extra steps obviously add extra complexity, cost, time, and effort.
Now let’s have a look at the tools you’ll need and then the procedure itself.
Tools To Replace Starter Motor
“It depends” is a useless answer to any question, and I try hard not to use it. But here it may be appropriate. The tools you need do depend on the challenge of the job at hand. If you are working on a family-sized motor you’ll have no problem with regular tools.
However, if your wheels are powered by a larger donkey, you’ll need a few pro tools. I’ll list them all here, together with a description if applicable and you can check most of them out on the Mechanics tools page.
- KAM tool – Keeps power supplied to the vehicles control modules
- Ratchet and sockets – Good selection of extensions and swivels are important for awkward fasteners
- Ratcheting wrenches – Ratcheting wrenches speed up the process
- Long swivel head ratchet – Telescoping handle with swivel head means you can apply force where you need it
- Breaker bar – Great when loosening larger bolts
- Long handled drivers – Great for reaching clips deep in the engine
- Pry bar – Great when maneuvering larger components
- Pick set – Used when opening wiring connectors with brittle release tabs
- Mirror – Used to see fasteners that are obscured from view
- Light – I can’t work without it
- Magnet – Grabbing those fasteners that make an run for it
- Bungees – Used when holding attached components out of the work area
- Pliers – Used when removing clips and clasps
- Clamp removal tool – Used when removing hose pipe clamps in impossible locations
- Jack – Used to access the underside of the vehicle
- Axle stands – Used to access the underside of the vehicle
- Creeper – Used to work under the vehicle
- Impact wrench – Used when removing larger components like exhaust unions or support
Your job may not require all these tools but most are needed.
Use A KAM Tool Before Disconnecting Battery
No matter which engine’s powertrain layout. You’ll need to fit a KAM tool. It’s easy to fit and will save you a ton of extra work and possibly a trip to the dealer.
What is a KAM tool?
It is a simple tool that powers your car’s control modules while the battery is disconnected. The problem with disconnecting the battery is, it kills the power to the car’s computers.
Modern control modules are sophisticated, they learn and adapt as you drive the vehicle. They also allow for wear and tear on a car’s components. Removing the battery without maintaining power to the control modules causes these leaned settings to be lost.
Your car will need to learn these over. For most cars this isn’t a huge issue, driving the car a few miles will help it learn the optimal settings but some cars may experience more persistent issues with HVAC, engine idling, transmission gear changes, etc.
When these symptoms persist a date with the main dealer or sophisticated bi-directional tool is required to calibrate the various systems.
I use an Autel bi-directional scan tool and you’ll find a link to both the scan tool and the KAM tool on the Auto electrical repair tools page.
Fitting a Kam Tool:
The KAM tool as you know supplies power to the car’s computers while the battery is disconnected. The tool obviously needs to be fitted before removing the car’s battery cable.
The tool is equipped with crocodile clips at one end and an OBD plug at the other. The tool offers two possible ways to power it up, either connect to a battery using the provided crocodile clips or connect to a donor vehicle via a12 volt plug provided.
Using the vehicle’s own battery is the more usual way. First, connect the crocodile clips to the battery in the usual fashion. Red to red positive sign and black to negative ground
The cable is long enough to reach from the car’s battery to the OBD port located on the driver’s side under the dash panel. Plug in the OBD plug and check for the light indicator, that’s it.
Your car’s learned settings are safe so long as the crocodile clips remain connected. If there is a danger of them becoming disconnected, go ahead and remove the battery from the car and set it to one side out of the work area. You’ll find a good KAM tool on the Mechanics tool page.
Replacing Starter On Front Wheel Drive
The transverse front-wheel drive is as you know usually the easier model to work on unless of course, the engine is unusually large. The starter motors on transverse models are usually located at the front of the engine. This is the ideal location for the starter as you won’t need to work under the car, a real bonus unless you have access to a hoist.
Sadly not all transverse starters live here, some live at the back of the engine and that usually involves climbing under the vehicle. And the story can get worse, if the starter lives at the back of the engine and the engine is large, it’s likely you’ll need to remove other components.
My advice – for more challenging-looking engines consult a workshop manual. You don’t want to remove more components than is necessary.
It’s not unusual for more challenging setups to require half shaft removal, exhaust, pipework, motor mount.
But let’s look at what the more common straightforward starter motor replacement procedure on a transverse front-wheel drive vehicle might look like:
- Fit KAM tool
- Remove battery negative terminal
- Remove air box assembly (most vehicles)
- Remove wiring harness from rear of starter
- Remove starter bolts
- Maneuver starter backways from the transmission
Replacing Starter On Rear Wheel Drive
Replacing the starter on a longitudinal rear-wheel-drive vehicle isn’t necessarily more challenging than the transverse front-drive vehicles. In fact, in many cases, the rear-drive starter motor offers a ton more room to work.
The trade-off is that you’ll be working on your back under the car. As a lifelong mechanic that’s done it both ways, working on your back is the least fun, or maybe I’m just doing it all wrong.
On a hoist replacing a starter motor on a rear-drive car is easy, with lots of room to work with few to no other components to impede your progress. Of course, there are large motor exceptions.
I’ve worked on a VW Phaeton for example and when I referred to the workshop repair manual under “Starter motor replacement” it states in a dry Germanic way – “Remoffe engine”.
It’s not uncommon to remove engine supports, motor mounts, exhausts, etc. in order to make room to work or to gain enough space to free the starter. Starters are bulky bits of kit.
Now let’s look at what the more common straightforward starter motor replacement procedure on a longitudinal rear-wheel-drive vehicle might look like:
- Fit KAM tool
- Remove battery negative terminal
- Jack vehicle
- Secure vehicle on axle stands
- Remove wiring harness from rear of starter
- Remove starter bolts
- Maneuver starter backways from the transmission
How Long Should Replacing A Starter Motor Take?
A straightforward starter removal should take more than an hour and another hour to fit the replacement. A more challenging replacement procedure may take four hours.
At the upper end, a whole day or eight hours could be spent replacing a starter motor. That’s assuming several other components also need to be removed and you don’t have the use of important time-saving tools like an impact wrench, hoist, etc.
My best advice, buy a digital repair manual for your car and be prepared for the task at hand. Understand what components need to be removed and in what order, you’ll also know what tools or parts you’ll need ahead of time.
Check out the Mechanics tools page where I list many of my favorite tools including the online workshop manuals I use.
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John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.