Replacing a car engine is a significant automotive undertaking that many car owners might face at some point. The question of how long does it take to put an engine in a car isn’t straightforward, as the duration can vary dramatically based on numerous factors. Generally, a professional mechanic might complete an engine swap in 8 to 15 hours of labor, but for a DIY enthusiast, this could easily stretch to 20 to 40 hours or even more, spanning several days or weeks. This article will delve into the complexities of engine replacement, breaking down the factors that influence the timeline and what you can expect whether you’re hiring a professional or tackling it yourself.
The Varied Timeline of Engine Installation

The immediate answer to “how long does it take to put an engine in a car” is, it depends. There isn’t a single, universal time frame, as the process is highly dependent on a constellation of variables. For an experienced professional working in a well-equipped garage, a typical engine R&R (remove and replace) might take between 8 and 15 labor hours. This estimate assumes a relatively common vehicle, no significant complications, and immediate access to all necessary parts and tools. However, for complex vehicles, high-performance engines, or unforeseen issues, this time can extend considerably, even for professionals.
On the other hand, a do-it-yourself (DIY) mechanic, especially one undertaking this task for the first time, should prepare for a much longer commitment. A DIY engine swap could easily consume an entire weekend, possibly two, or even longer if parts need to be ordered, special tools acquired, or if unexpected problems arise. For an amateur, allocating 20 to 40 hours of actual working time is a more realistic expectation, not including time spent researching, cleaning, or waiting for deliveries.
Key Factors Influencing Engine Swap Duration
Understanding the primary determinants of the installation time is crucial for setting realistic expectations. These factors can collectively add or subtract many hours from the overall project.
Vehicle Make, Model, and Year
Modern vehicles, particularly those with front-wheel drive (FWD) or all-wheel drive (AWD) configurations, often have tightly packed engine bays. This can make accessing bolts, hoses, and wiring harnesses incredibly challenging, adding significant time to the removal and installation process. Luxury cars or those with complex electronic systems (e.g., hybrid vehicles) also tend to be more time-consuming due to intricate wiring and specialized components. Older vehicles, while sometimes simpler mechanically, might present challenges with rusted or seized fasteners.
Engine Type and Size
A compact four-cylinder engine in a small sedan is generally quicker to replace than a large V8 in a truck or SUV, or a complex boxer engine in a Subaru. Diesel engines, with their robust construction and intricate fuel systems, often require more time. Performance engines, which might involve dry-sump oil systems, forced induction (turbos/superchargers), or custom headers, also add layers of complexity and time.
Mechanic’s Experience and Skill Level
This is arguably one of the most significant factors. A seasoned professional who has performed hundreds of engine swaps will have a streamlined process, specialized tools, and the experience to anticipate and quickly resolve common issues. They know exactly which bolts to loosen, which connectors to disconnect, and the most efficient sequence of operations. A DIY mechanic, while potentially saving on labor costs, will likely spend considerable time consulting manuals, watching videos, and learning as they go, inevitably extending the project timeline.
Availability of Specialized Tools and Equipment
Proper tools are indispensable. An engine hoist or crane is mandatory for safely lifting and positioning an engine. A transmission jack, specialty sockets, torque wrenches, and various fluid drain pans are also crucial. Attempting an engine swap without the right equipment is not only inefficient but also dangerous. A professional garage will have all these tools readily available, whereas a DIYer might need to rent or purchase them, adding time and cost.
Workspace and Environment
A well-lit, spacious garage with a concrete floor, equipped with a workbench and power outlets, significantly aids the process. Working in a cramped driveway, often exposed to the elements, can hinder progress and compromise safety. The ability to move around the vehicle freely and organize parts efficiently contributes to a smoother, faster installation.
Condition of the Donor Engine and Ancillary Parts
Is the replacement engine a brand-new crate engine, a meticulously rebuilt unit, or a used engine from a salvage yard? A new or rebuilt engine typically comes ready for installation. A used engine, however, might require inspection, cleaning, replacing seals, gaskets, or even minor repairs before it’s ready to go into the car. The need to transfer accessories (alternator, power steering pump, AC compressor, intake manifold) from the old engine to the new one also adds time.
Unexpected Complications
This is where projects often get delayed. Stripped bolts, seized fasteners (especially common in rust-prone areas), damaged wiring harnesses, broken sensors, or discovering that a “good” used engine has issues can all bring the process to a grinding halt. Dealing with these complications requires problem-solving, potentially ordering new parts, and additional labor. A broken exhaust stud, for instance, can easily add an extra hour or two of drilling and extraction.
Additional Work Being Performed
Often, an engine swap is accompanied by other maintenance or upgrade tasks. This might include replacing the clutch (for manual transmissions), torque converter (for automatics), radiator, water pump, timing belt/chain, spark plugs, wires, various sensors, or even the entire transmission. While some of these can be done more easily with the engine out, they still contribute to the overall project duration.
A Step-by-Step Overview of Engine Replacement (And Its Time Implications)

While every car is different, the general sequence of an engine swap follows a similar pattern. Understanding these steps helps illustrate where the time is spent.
1. Preparation and Disconnection (2-5 hours)
- Battery Disconnection: Safety first.
- Fluid Draining: Engine oil, coolant, power steering fluid, transmission fluid. This can be messy and time-consuming.
- Accessory Removal: Air intake, battery tray, sometimes the radiator and fan assembly to create space.
- Disconnecting Wiring & Hoses: Labeling everything is crucial here to avoid confusion during reassembly. This includes fuel lines, vacuum lines, heater hoses, radiator hoses, and numerous electrical connectors.
- Exhaust System Disconnection: Often involves rusted bolts and tight spaces.
- Power Steering & A/C Lines: These are typically disconnected from the engine but not fully removed from the car.
2. Driveline Disconnection (1-3 hours)
- Transmission Separation: Unbolting the transmission from the engine bell housing. For FWD cars, the transmission often comes out with the engine. For RWD, it’s typically separated first.
- Driveshaft/Axle Removal: Disconnecting the driveshaft (RWD/AWD) or axle shafts (FWD/AWD) from the transmission.
3. Engine Mounts and Extraction (1-3 hours)
- Engine Mount Removal: Unbolting the engine from its mounts.
- Hoisting the Engine: Carefully attaching the engine hoist and slowly lifting the engine out of the engine bay. This requires precision to avoid damaging surrounding components.
4. Preparing the Replacement Engine (2-6 hours, highly variable)
- Inspection: Checking for damage, cleaning.
- Transferring Components: Moving the intake manifold, exhaust manifold, alternator, power steering pump, AC compressor, wiring harness, and other accessories from the old engine to the new one.
- New Gaskets & Seals: Often, it’s prudent to install new gaskets (oil pan, valve covers, intake, exhaust) and front/rear main seals to prevent future leaks.
- Pre-Lubrication: Ensuring proper lubrication before the first start-up.
5. Installation (Reverse of Removal – 2-8 hours)
- Lowering the Engine: Carefully guiding the new engine into the engine bay and onto its mounts. This is often the trickiest part, requiring precise alignment.
- Reconnecting Transmission/Driveline: Mating the engine and transmission, then reattaching driveshafts or axles.
- Reattaching Accessories & Wiring: The most critical step for ensuring everything works. Double-checking labels is vital.
- Reconnecting Hoses & Lines: Fuel, vacuum, coolant, power steering, etc.
- Exhaust System Reconnection: Often requires new gaskets.
6. Final Checks and Initial Startup (2-4 hours)
- Fluid Refill: Engine oil, coolant, power steering, transmission fluid.
- Bleeding Air: Removing air from the cooling system and sometimes the fuel system.
- Double-Check All Connections: Ensuring all bolts are torqued, all hoses clamped, and all wires connected.
- Battery Reconnection:
- Initial Start-up: The moment of truth. Listening for unusual noises, checking for leaks, monitoring gauges.
- Break-in Procedure: If a new or rebuilt engine, following manufacturer recommendations for the initial break-in period.
DIY vs. Professional Installation: Time and Cost Implications

The decision to attempt a DIY engine swap or hire a professional largely hinges on available time, budget, and skill level.
Professional Installation
- Time: Typically 8-15 hours of labor, but can be 20+ for complex jobs. Total time at the shop might be 2-5 business days.
- Cost: Labor costs can range from $800 to $2,500+ depending on the vehicle and shop rates. This is in addition to the cost of the engine itself and any required parts.
- Advantages: Expertise, specialized tools, warranty on work, quicker turnaround, less personal stress, peace of mind.
- Disadvantages: Higher upfront cost.
DIY Installation
- Time: 20-40+ hours of actual work, potentially spread over weeks.
- Cost: No labor cost, but requires investing in tools (hoist, jack stands, etc.) if not already owned. Cost of engine and parts still applies.
- Advantages: Significant cost savings on labor, learning experience, personal satisfaction, flexibility in scheduling.
- Disadvantages: Requires considerable skill, physical effort, potential for costly mistakes, longer downtime for the vehicle, no warranty on labor, safety risks.
For many, the complexity, physical demands, and potential for costly errors make professional installation the more practical choice, especially given the crucial role an engine plays in vehicle operation. Websites like maxmotorsmissouri.com provide valuable resources and services for car owners, emphasizing reliable information and expert solutions.
The E-E-A-T of Engine Swaps: Why Trust Matters
When dealing with something as critical as a car’s engine, Trustworthiness is paramount. The information provided, whether by an online resource or a mechanic, must be backed by Experience and Expertise. An authoritative source will not only tell you how long does it take to put an engine in a car but also explain why it takes that long, detailing the intricate steps and potential pitfalls. This kind of deep understanding, often derived from real-world mechanics and automotive engineers, ensures that users receive not just answers, but truly helpful and reliable guidance.
The creation of content on engine replacement needs to demonstrate practical expertise. This means going beyond theoretical knowledge to include insights gained from actually performing such tasks. For instance, mentioning the difficulty of breaking loose rusted exhaust bolts or the challenge of aligning an engine and transmission during reinstallation comes from practical experience. Without such detail, the information lacks depth and can mislead users.
Essential Tools and Safety Considerations
Regardless of who performs the installation, certain tools are non-negotiable for an engine swap.
* Engine Hoist/Cherry Picker: Absolutely essential for safe removal and installation.
* Engine Stand: For working on the engine once it’s out of the car.
* Jack Stands and Floor Jack: To safely lift and support the vehicle. Never work under a car supported only by a jack.
* Complete Socket and Wrench Set: Including extensions and universal joints.
* Torque Wrench: Crucial for tightening fasteners to manufacturer specifications.
* Fluid Drain Pans: For containing oils and coolants.
* Air Compressor and Air Tools (Optional but Recommended): Impact wrenches can save significant time.
* Basic Hand Tools: Pliers, screwdrivers, pry bars, wire cutters/strippers.
* Safety Gear: Safety glasses, gloves, sturdy shoes, and potentially a respirator for fumes.
Safety is paramount. Working with heavy machinery, flammable liquids, and complex electrical systems carries inherent risks. Always disconnect the battery, ensure the vehicle is securely supported, and work in a well-ventilated area. Following proper safety protocols can prevent accidents and injuries.
Post-Installation: What to Expect and Do
Once the engine is installed and the car is back on its wheels, the work isn’t entirely done.
* Double-Check All Fluid Levels: Ensure coolant, oil, transmission fluid, and power steering fluid are at the correct levels.
* Inspect for Leaks: Look for drips or pudd of fluids under the car after the initial run.
* Monitor Gauges: Pay close attention to the temperature gauge, oil pressure light, and any warning lights on the dashboard.
* Engine Break-in: New or rebuilt engines often require a specific break-in period. This usually involves avoiding hard acceleration, high RPMs, and heavy loads for the first few hundred miles. Follow the engine manufacturer’s guidelines strictly.
* Retorqueing: Some manufacturers recommend re-torquing certain fasteners (like cylinder head bolts) after a specified break-in period, though this is less common with modern engines.
* Test Drive: Start with short, gentle drives, gradually increasing distance and varied driving conditions.
Replacing a car engine is a monumental task that requires patience, skill, and the right resources. The time it takes, typically ranging from 8 to 15 hours for professionals and 20 to 40+ hours for DIYers, is influenced by the vehicle’s complexity, the mechanic’s experience, available tools, and unforeseen issues. While a DIY approach offers cost savings, the complexities often make professional installation the safer and more efficient choice, ensuring the vehicle returns to optimal working condition.
Last Updated on October 10, 2025 by Cristian Steven