It may be hard to believe, but most mechanical engineers designing your cars have no clue how to fix them. That’s because engineering and automotive repair are two very separate entities. Here’s the difference.




I can’t tell you how many times I’ve told someone I’m a mechanical engineer, only for them to respond by describing the strange noise their car is making, in hopes that I can help them fix it. People assume engineers can wrench because engineering is a field devoted to understanding how things work. But as Engineering Explains’ Jason Fenske points out in the video below, knowing the theory behind how something works and grasping how to fix it are not the same. Nope, not even close.

The Difference Between A Mechanical Engineer And A Mechanic

Mechanical engineering is a rather broad discipline whose ultimate goal is to efficiently design and optimize mechanical systems. It’s a field that starts with a vision for a product, often requires complex mathematical analysis, and results in what is hopefully a robust, lean, well-performing part, machine or process.


Becoming a mechanical engineer in the U.S. simply requires a four-year undergraduate degree, and the overwhelming majority of programs do not include any mandatory automotive wrenching courses. To prove this point, here’s a list of all the engineering classes I took in college, along with course descriptions courtesy of Lou’s List:

Introduction To Engineering: “ENGR 1620 is a cornerstone course for first year engineering students. They are introduced to the philosophy and practice of engineering through hands-on experience in developing solutions for various open-ended, realistic challenges while considering the various contexts in which these challenges occur.” Single Variable Calculus I: “The concepts of differential and integral calculus are developed and applied to the elementary functions of a single variable. Limits, rates of change, derivatives, and integrals. Applications are made to problems in analytic geometry and elementary physics. For students with no exposure to high school calculus.” Intro To Chemistry for Engineers: “Introduces the principles and applications of chemistry. Topics include stoichiometry, chemical equations and reactions, chemical bonding, states of matter, thermochemistry, chemical kinetics, equilibrium, acids and bases, electrochemistry, nuclear chemistry, and descriptive chemistry of the elements.” Intro Chemistry Lab: “Introduction to experimental chemistry, developing laboratory skills & safety. Students plan & implement chemistry experiments in cooperative 4-person teams using a guided inquiry approach. Process skills include developing procedures, data analysis, oral & written communication. Mathematica as a computational tool.” Single Variable Calculus II: “Includes the concepts of differential and integral calculus and applications to problems in geometry and elementary physics, including inverse functions, indeterminate forms, techniques of integration, parametric equations, polar coordinates, infinite series, including Taylor and Maclaurin series.” Introduction To Programming: “A first course in programming, software development, and computer science. Introduces computing fundamentals and an appreciation for computational thinking.” Intro To Science and Engineering Of Materials: “Provides the scientific foundation for understanding the relations between the properties, microstructure, and behavior during use of metals, polymers, and ceramics. Develops a vocabulary for the description of the empirical facts and theoretical ideas about the various levels of structure from atoms, through defects in crystals, to larger scale morphology of practical engineering materials.” General Physics I: “First semester of introductory physics for engineers and scientists. Classical mechanics, including vector algebra, particle kinematics and dynamics, energy and momentum, conservation laws, rotational dynamics, oscillatory motion, gravitation, thermodynamics, and kinetic theory of gases.” General Physics Workshop: “A required two-hour workshop accompanying [General Physics I], including laboratory and tutorial activities.” Multivariable Calculus: “Topics include vectors in three-space and vector valued functions. The multivariate calculus, including partial differentiation, multiple integrals, line and surface integrals, and the vector calculus, including Green’s theorem, the divergence theorem, and Stokes’s theorem.” Applied Probability and Statistics: “Examines variability and its impact on decision-making. Introduces students to basic concepts of probability, such as random variables, probability distribution functions, and the central limit theorem. Based on this foundation, the course then emphasizes applied statistics covering topics such as descriptive statistics, statistical inference, confidence intervals, hypothesis testing, correlation, regression modeling, statistical quality control.” Intro to Mechanical Engineering: “Overview of the mechanical engineer’s role as analyst and designer. Introduction to manufacturing tools, equipment, and processes; properties of materials relative to manufacture and design; communication through engineering graphics; engineering drawing interpretation, sectioning, auxiliary views; and analysis and design of mechanical devices. Workshop includes CAD and solid modeling.” Statics: “Basic concepts of mechanics, systems of forces and couples: equilibrium of particles and rigid bodies; analysis of structures: trusses, frames, machines; internal forces, shear and bending moment diagrams; distributed forces; friction, centroids and moments of inertia; introduction to stress and strain; computer applications.” General Physics II: Electricity & Magnetism, Optics: “Second semester of introductory physics for engineers and scientists. Electrostatics, including conductors and insulators; DC circuits; magnetic forces and fields; magnetic effects of moving charges and currents; electromagnetic induction; Maxwell’s equations; electromagnetic oscillations and waves. Introduces geometrical and physical optics.” General Physics II Workshop: “A required two-hour workshop accompanying [General Physics II], including laboratory and tutorial activities.” Ordinary Differential Equations: “First order differential equations, second order and higher order linear differential equations, reduction of order, undetermined coefficients, variation of parameters, series solutions, Laplace transforms, linear systems of first order differential equations and the associated matrix theory, numerical methods. Applications.” Thermodynamics: “Includes the formulation of the first and second laws of thermodynamics; energy conservation; concepts of equilibrium, temperature, energy, and entropy; equations of state; processes involving energy transfer as work and heat; reversibility and irreversibility; closed and open systems; and cyclic processes.” Strength of Materials: “Normal stress and strain, thermal strain, shear stress, shear strain; stress and strain transformations; Mohr’s circle for plane stress and strain; stresses due to combined loading; axially loaded members; torsion of circular and thin-walled closed sections; statically indeterminate systems; deformation, strains and stresses in beams; beam deflections; column stability.” Dynamics: “Kinematic and kinetic aspects of motion modeling applied to rigid bodies and mechanisms....Use of work-energy and impulse-momentum motion prediction methods. Use of Cartesian and simple non-Cartesian coordinate systems. Rotational motion, angular momentum, and rotational kinetic-energy modeling; body mass rotational moment of inertia. Relative-velocity and acceleration.” Intro to Aerospace Engineering: “Historical introduction, standard atmosphere, basic aerodynamics, airfoils and wings, flight mechanics, stability and control, propulsion (airbreathing, rocket and space), orbital mechanics.” Fluid Mechanics: “Introduction to fluid flow concepts and equations; integral and differential forms of mass, momentum, and energy conservation with emphasis on one-dimensional flow; fluid statics; Bernoulli’s equation; viscous effects; Courette flow, Poiseuille flow, and pipe flow; boundary layers; one-dimensional compressible flow; normal shock waves; flow with friction or heat addition; isothermal flow; and applications.” Aerospace Structures: “Analyzes the design of elements under combined stresses; bending and torsional stresses in thin-walled beams; energy and other methods applied to statically determinate and indeterminate aerospace structural elements; buckling of simple structural members; and matrix and finite element analysis.” Mechanical Systems Modeling: “Presents general concepts of dynamical systems modeling and provides mathematical tools to develop and analyze models that describe input/output behaviors of physical systems. Topics include basic elements of mechanical systems, transfer functions, frequency response, stability and poles, resonance and natural frequency, transient and time constant, steady state and DC gain, block diagrams.” Experimental Methods Lab: “The study of basic concepts and methods in engineering measurements and data analysis. Basic topics include mechanical and electrical sensors and measurement instruments, measurement uncertainty, statistic and data analysis. Additional topics include digital signal processing and data acquisition systems using Labview. Applications are to mechanical and aero/thermofluids devices.” Heat and Mass Transfer: “Analysis of steady state and transient heat conduction in solids with elementary analytical and numerical solution techniques; fundamentals of radiation heat transfer, including exchange among black and diffuse gray surfaces; free and forced convective heat transfer with applications of boundary layer theory and an introduction to mass transfer by diffusion using the heat-mass transfer analogy.” Machine Elements and Fatigue Design: “Applies mechanical analysis to the basic design of machine elements; basic concepts in statistics and reliability analysis, advanced strength of materials, and fatigue analysis; and the practical design and applications of materials to fastening systems, weldments, power screws, springs, journal and anti-friction bearings, gears, brake clutches and flexible power transmission elements.” Mechanical Engineering Lab: “Application of experimental methods to the design of experiments. Hypothesis testing and uncertainty assessment. Examination of test equipment and procedures through the operation of test facilities for heat transfer, mechanical and fluid systems including data acquisition and processing systems.” Mechatronics: “Presents the synergistic integration of mechanical engineering with electronics and computer control in the design of industrial products and processes. Surveys basic electronics, electromechanical actuators, analog and digital signals, sensors, basic control algorithms, and microcontrol programming. Weekly laboratory exercises and a final design project.” Linear Algebra: “Analyzes the systems of linear equations; vector spaces; linear dependence; bases; dimension; linear mappings; matrices; determinants; quadratic forms; eigenvalues; eigenvectors; orthogonal reduction to diagonal form; inner product spaces; numerical methods; geometric applications.” Aerospace Materials: “Introduces physical-chemical/microstructural and working mechanical properties, along with practical applications, for materials of wide interest on aerospace materials. Includes common metal, polymer, ceramic, and composite materials. Topics include standard materials names/designations; standard forming methods; usual strengthening means; temperature and temperature-history effects.”

Air Breathing Propulsion: “Reviews thermodynamics of compressible fluids and includes analysis of the mechanisms for thrust generation in aerospace propulsion systems; performance and cycle analysis of air-breathing engines, emphasizing turbojets, turbofans, turboprops and ramjets; aerothermodynamics of inlets, diffusers, combustors, and nozzles; performance of axial-flow and centrifugal compressors; turbines; and the matching of engine components.” Engineering Ethics and Professional Responsibility: “This course focuses on ethical issues in engineering. The key theme is that ethics is central to engineering practice. The professional responsibilities of engineers are examined. Students produce an STS Research paper linked to their technical thesis project and complete all of the requirements for the senior thesis.” Capstone Project: Electric Vehicle: “Design and build a rear-wheel drive, rear-motor electric vehicle out of a Volkswagen Jetta.”

As you can see, it’s almost pure theory, though I did take a number of labs meant to help students visualize and understand real-world applications of all the science and math learned in the classroom. But in these labs, we often just took measurements from things like pitot-static tubes, flow meters, and strain gauges, and then analyzed the data to gain greater understanding of how things work. We weren’t really building anything from scratch, and we sure as heck weren’t fixing anything.


My experience was similar to Jason Fenske’s in that both of our engineering programs only saw true, hands-on, Build Something From Nothing applications of theory in the fourth and final year of study. In my case, that hands-on application was a year-long capstone project involving the conversion of a 2001 Volkswagen Jetta into a rear-wheel drive, rear-engine electric sports car.

I did learn some wrenching in that class, but I only took it because I wanted to. I could have easily fulfilled that capstone requirement by focusing on robotics, medical equipment, aerodynamics or something else not at all related to automobiles. Then I’d literally have learned zero in college about how to build or fix cars, and I’d still have been qualified to design your next car at a major OEM.


And that’s the thing people need to remember: engineers like me and Toyota’s Jackie Birdsall can wrench because we took it upon ourselves to learn, not because it’s a prerequisite to become an engineer. Jackie took a welding course and worked at Pep Boys, while I went out and bought a junky 225,000 mile Jeep Cherokee without having funds to pay a trained mechanic.

Plenty of other engineers get their wrenching fixes in by participating in Formula SAE, Baja SAE or other car-related team projects (whose members are not just engineers, I should add). But I’ll reiterate: almost all engineers do this on their own initiatives, not because they have to.




All Car Engineers Should Know How To Wrench

Many of the folks who helped me fix my 1948 Willys were automotive engineers.


In other words, many mechanical engineers leave college without learning a single thing about how to fix cars. They can, for example, calculate the optimal flow versus pressure drop of an engine’s water pump, and they can even tell you the best materials to use for the bearings and impeller. Plus, they can tell you how to actually manufacture the pump as cheaply and efficiently as possible. But hand a typical cooling system engineer a wrench and ask them to swap out your water pump, and chances are, you will witness something pathetic.

This is, obviously, a problem. How can you design the best car without having seen how engineers before you solved complex engineering conundrums? What’s more, how can you truly understand the effect that your designs have on serviceability if you don’t wrench? We all know how hard it is to work on cars these days; you have to wonder how much of that can be attributed to engineers with zero wrenching backgrounds.




To fix this, some car companies bring mechanics into design meetings. I can’t tell you how many times I’ve been in a meeting where a technician has had to yell at a 22 year-old Fresh Out Of College engineer because the youngster decided to do something like package a brake vacuum pump where it would require the removal of the entire engine for service.

There are a number of reasons why so many engineers can’t wrench, the primary one being that engineers aren’t required to learn it in college. But there’s also the United Auto Workers union, the UAW, which prohibits engineers from working on cars in the workplace.


When I worked at Fiat Chrysler, I can’t tell you how frustrating it was being the guy with the graphing calculator and khakis, when I really wanted to be the guy with the graphing calculator and overalls. If I had actually tried fixing something or installing a part I designed, union members could have filed a grievance and I’d have gotten in trouble; this is a giant load of bullshit, and it needs to change.

Engineers Tend To Make Good Wrenchers

Even if being an engineer doesn’t necessarily mean you know how to wrench, I think having engineering knowledge makes wrenching come a lot easier. It’s for this reason that I’d probably guess there are more automotive engineers who live and breath wrenching than there are, say, English majors. In fact, the entire team of friends that helped me get my two Moab projects (see picture above) ready for their epic road trips was made up of auto engineers with excellent wrenching skills.


I think knowing how parts work makes it easier to troubleshoot faults, and the curiosity that engineers have to learn more often drives us to want to take stuff apart. These are ingredients for a great wrencher.

Plus, in my experience, having a wrenching background gets you lots of “street cred” in the auto engineering world. I’m convinced that my plights wrenching on old Jeeps are what helped me get both of my gigs at Cummins and Fiat Chrysler. Engineers who can “walk the walk,” so to speak, are definitely desirable in the industry.


But sadly, they are rarer than you’d think.