Under the Hood · Leader's Guide

Reading Under the Hood together

This guide is for anyone reading Under the Hood with other people: a small group, a newcomers' class, or a volunteer sitting down with a customer or a friend who is new to faith. It follows the book one chapter at a time, twelve sessions in all.

The book was written for people with little or no church background. Your group should feel the same way. No one needs to know the Bible, pray out loud, or have their mind made up. The only requirement is honesty, and you can model that by going first.

Before you start

• Start where your group is. The book's discussion questions move from the more accessible (personal experience, observation) toward the more personal (belief, response). You don't have to use all four every time. Go as deep as trust allows.
• There are no trick questions. The goal isn't to test what anyone knows. It's to help people think honestly about what they believe, and why.
• Skip the jargon. If you use a church word (grace, sin, repentance), say what it means in plain English. The book does this on every page, and you can too.
• Keep it small. These questions work in a group of six or eight, and they work just as well one-on-one over coffee or at a picnic table outside the shop.
• Have extra copies. Someone may show up who hasn't read the chapter. Each one is short enough to read aloud together in a few minutes.

A 60-minute gathering

Twelve-week plan

One chapter a week. Read it beforehand if you can, or read it together at the start.

Session by session

Session 1: Broken is broken

Read: Chapter 1, "Every Car That Comes Through Our Doors" · Open with: Genesis 1:31

The big idea: Every car and every person is broken, and saying so is a diagnosis, not an insult.

To open: What's the worst car you've ever owned, and what was wrong with it?

1. When you think about your own life, is there an area where you sense a gap between who you are and who you were meant to be? What does that gap feel like?
2. The chapter says honesty is an act of love. Do you agree? Can you think of a time when someone’s honest words about you were hard to hear but ultimately helpful?
3. The Bible says God looked at what he made and called it “very good.” Does the idea that human beings were originally designed for something good resonate with you, or does it feel hard to believe? Why?
4. What do you think is the biggest thing broken in the world today? What about in your own life?

This week: Notice one moment this week when you wanted to be told everything was fine. Ask yourself what the honest answer would have been.

Session 2: The diagnostic

Read: Chapter 2, "The Diagnostic" · Open with: Romans 3:20

The big idea: The law fixes nothing, but it tells the truth, and truth is where every real repair begins.

To open: Have you ever had a mechanic, doctor, or friend tell you the real problem was something other than what you thought?

1. Have you ever had a conscience that bothered you about something — a quiet sense that you’d done something wrong? What did you do with that feeling?
2. The chapter says the standard isn’t other people — it’s the original design. How do you usually measure whether you’re a “good person”? What do you compare yourself to?
3. Does the idea of God having a moral standard feel comforting, threatening, or something else? Why do you think it lands that way for you?
4. If the law is like a diagnostic — it shows the problem but doesn’t fix it — what do you think fixes it? Where does real change come from?

This week: Read the short list in the chapter (love God, love your neighbor, don't lie, don't steal, keep promises) and hold one day of your week up against it. Just notice. Don't try to fix anything yet.

Session 3: Driving on a warning light

Read: Chapter 3, "Deferred Maintenance" · Open with: Romans 1:21

The big idea: Your conscience is a warning light, and warning lights are gifts.

To open: What's the longest you've ever driven with a warning light on?

1. Is there an area of your life where you’ve been “driving on a warning light” — something you know needs attention but have been putting off? What’s made it hard to deal with?
2. The chapter says we become experts at ignoring our conscience. What are the most common ways people do that? Which ones do you recognize in yourself?
3. The chapter calls warning lights “gifts.” Does that reframe feel true to you, or forced? Can you think of a time when a warning sign in your life turned out to be a grace?
4. What would it take for you to stop deferring and start dealing? What feels like the biggest obstacle?

This week: Name one warning light you've been ignoring, and tell one person you trust about it this week.

Session 4: The one who made the machine

Read: Chapter 4, "The Master Mechanic" · Open with: John 1:1–3; Hebrews 4:15

The big idea: Jesus made the machine, and then he became it: fully God and fully human.

To open: Who is the best mechanic, or the best at anything, you've ever watched work?

1. Before reading this book, who did you think Jesus was? Has anything shifted or surprised you?
2. The chapter says Jesus “got his hands dirty” — that he entered human suffering rather than observing it from a distance. What does it mean to you that God would do that?
3. Hebrews 4:15 says Jesus was “tempted as we are, yet without sin.” Does the idea that Jesus understands human struggle from the inside make him feel more or less relatable to you?
4. If Jesus really is who the Bible says he is — the one who designed you and knows you completely — what would it change about how you think about your life?

This week: Read John chapter 1 this week, slowly. Write down one thing it says about who Jesus is.

Session 5: God came himself

Read: Chapter 5, "He Came to Our Shop" · Open with: John 1:14; John 3:16–17

The big idea: God didn't send a manual. He came himself.

To open: When has someone shown up in person for you when they could have just sent a text?

1. The chapter says God didn’t send a pamphlet or a representative — he came himself. What does that tell you about the kind of God he is?
2. John 3:16 says God “so loved” the world. Have you ever found it hard to believe that God’s love extends specifically to you, personally? What makes that difficult?
3. The volunteers at The Garage show up on Saturdays because love has to go somewhere. Is there someone in your life right now whose love for you has felt like a small echo of something bigger?
4. If God’s love is as described in this chapter — specific, personal, costly, not waiting for you to deserve it — how does that compare to how you’ve generally understood love?

This week: Read John 3:16–17 once a day this week, and put your own name where it says "the world."

Session 6: Someone paid the bill

Read: Chapter 6, "The Bill Was Paid" · Open with: Romans 5:8; Isaiah 53:5; Mark 10:45

The big idea: Even free repairs have a bill, and Jesus paid ours.

To open: Has anyone ever quietly paid for something for you: a meal, a repair, a bill? How did it feel?

1. The chapter says “someone always has to pay the bill.” How does that principle show up in your own experience of life — in relationships, in consequences, in the way things work?
2. The cross holds together two things: God’s justice (sin has real consequences) and God’s love (he absorbs those consequences himself). Does that combination make sense to you? Which side of it is harder to accept?
3. Mark 10:45 says Jesus came “to give his life as a ransom for many.” What does it do to you emotionally to think about someone paying a price on your behalf that you couldn’t pay?
4. The chapter says the resurrection is the proof that the payment was accepted. Do you find the resurrection easy or hard to believe? What’s your biggest question about it?

This week: Write down your biggest question about the cross or the resurrection, and bring it next week or ask someone you trust.

Session 7: No one is a total loss

Read: Chapter 7, "Total Loss… or Total Restoration?" · Open with: Ephesians 2:4–5

The big idea: God doesn't use the insurance company's math. Grace restores people who look like total losses.

To open: Have you ever kept something running long after everyone told you to give up on it?

1. Have you ever felt like a “total loss” — like you were too far gone, too broken, too much of a mess for things to be fixed? What brought you to that place?
2. The chapter says grace comes to people who haven’t earned it, specifically because they haven’t earned it. Does that feel like good news, or does it feel too good to be true? Why?
3. Ephesians 2:4–5 says God loved us “even when we were dead in our trespasses.” The love came first, before any change. How does that order — love first, transformation second — strike you?
4. Is there anyone in your life you’ve written off as a “total loss”? What would it look like to extend grace to them the way this chapter describes God extending grace to us?

This week: Think of one person you've written off. Do one kind thing for them this week, without expecting anything back.

Session 8: Handing over the keys

Read: Chapter 8, "The Work Order" · Open with: Romans 10:9

The big idea: Faith is trust and repentance is a change of direction. You don't fix the car yourself. You hand over the keys.

To open: Who would you trust with your car keys without a second thought, and why them?

1. The chapter compares faith to handing over the keys. Is trust easy or hard for you? What makes you willing — or unwilling — to trust someone with something important?
2. Repentance is described as a change of direction, not just a feeling of guilt. What’s the difference? Can you think of a time in your life when you genuinely changed direction, not just felt bad?
3. The chapter says you don’t have to have everything figured out before you respond to Jesus. Does that lower the barrier for you, or does it feel like something is missing?
4. If someone asked you right now, “Are you ready to hand over the keys?” — what would your honest answer be? What’s holding you back, if anything?

This week: Read "A Prayer for the Broken" at the back of the book. If you mean it, pray it. If you're not ready, write down what's holding you back.

Session 9: Growth happens on the road

Read: Chapter 9, "Road Test" · Open with: Philippians 1:6

The big idea: God doesn't do half-repairs. What he starts, he finishes, and he does it on the road.

To open: What's something you got better at slowly, over a long time?

1. Have you ever met someone whose life seemed genuinely changed by their faith? What did that look like? What was different about them?
2. The chapter says the road test reveals things the shop couldn’t. What do you think are the “road conditions” in your life that would test who you really are?
3. Philippians 1:6 says God “will bring it to completion.” How does it feel to know that the responsibility for finishing the repair belongs to God, not to you?
4. What would it practically look like for you to “face the right direction” this week? What’s one small, concrete thing that might look different?

This week: Pick the one small, concrete thing you named in question 4 and do it. Read the Gospel of John a chapter at a time as you go.

Session 10: Faith gets its hands dirty

Read: Chapter 10, "Why We Do This" · Open with: 1 John 4:19; James 2:17; Matthew 25:40

The big idea: Good works don't earn the repair. They are the evidence it happened. We love because he first loved us.

To open: Who is someone who has helped you with their hands, not just their words?

1. 1 John 4:19 says, “We love because he first loved us.” Have you ever experienced love that came from somewhere bigger than the person giving it — love that seemed to overflow from them rather than originate with them?
2. The chapter says faith always produces something — it always gets its hands dirty. Do you agree? Have you seen examples of this, positive or negative?
3. James 2:17 says faith without works is dead. How do you personally distinguish between works that come from genuine love versus works done out of obligation or to earn something?
4. If someone looked at your average week, what would they conclude about what you love most? Does that match what you say you believe?

This week: Look at your calendar for the past week. Circle the hours you spent on someone else, and ask what you want next week to look like.

Session 11: Pass it on

Read: Chapter 11, "Pass It On" · Open with: John 15:12–13; Matthew 28:19–20

The big idea: People who have been loved are called to love. The fixed car doesn't stay in the garage.

To open: Think of a time someone helped you when you were stuck. What did they actually do?

1. Think of the most generous person you know. What do you think is the source of their generosity? Where does it come from?
2. Jesus says in John 15:13 that laying down your life for your friends is the greatest love. What does “laying down your life” look like in practical, everyday terms — not in theory, but in your actual relationships?
3. The chapter says you don’t have to be a mechanic to participate in this kind of love. What do you have — skills, time, resources, presence — that could be poured out for someone else?
4. Is there someone in your life right now who needs practical love — not advice, not prayers alone, but something concrete? What’s one thing you could actually do?

This week: Do the one concrete thing you named in question 4, this week. Or tell one person what has happened to you so far in this study.

Session 12: Where the road leads

Read: Chapter 12, "The Road Ahead" · Open with: Revelation 21:4–5

The big idea: The road goes somewhere. God is making all things new, and everyone is invited.

To open: What's the best road trip you've ever taken, and where were you headed?

1. Be honest: when you think about eternity — about what happens after you die — what do you actually think? What do you hope?
2. The chapter says knowing your destination changes how you drive. How would your daily choices look different if you genuinely believed this life was leading somewhere extraordinary?
3. Revelation 21:4–5 describes God making “all things new.” What is something broken in your life or in the world that you most want to see made new?
4. At the end of the book, we come back to Michael in his driveway, just trying to love someone practically. What’s your version of that — the simple, concrete thing you could do because you’ve been loved?

This week: Decide your next step and tell the group: keep reading the Bible, visit a church, talk with a pastor, or pick up a wrench and volunteer.

When someone is ready to hand over the keys

If someone in your group signals they're ready to respond to the Gospel, ready to "hand over the keys," don't rush past that moment. Take them to "A Prayer for the Broken" at the back of the book and pray it together.

Then connect them with a pastor or elder at a local church. The book is clear on this: that conversation matters more than finishing the study guide. Don't wait for session twelve.

If you're still figuring it out yourself

You may be leading this group and still working out your own answers to these questions. That's okay too. The road is long, and none of us has arrived. Keep asking. Keep driving.

You don't need to have the answer to every question someone raises. "I don't know, but let's find out" is an honest answer, and honesty is the whole point of this book.

Questions are from the discussion guide in Under the Hood: Why We Fix Cars, and Why That's Not Really the Point by Mark Sentell. The book is available in 3 formats on Amazon. marksentell.com/books/under-the-hood/