The Biggest Mistake Shop Owners Make with Josh Coomes and Brian Ramsburg
The Jaded Mechanic Podcast
The Biggest Mistake Shop Owners Make with Josh Coomes and Brian Ramsburg The Jaded Mechanic Podcast · Jul 21, 2026
The Biggest Mistake Shop Owners Make with Josh Coomes and Brian Ramsburg

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The Biggest Mistake Shop Owners Make with Josh Coomes and Brian Ramsburg
Term

service writers

A service writer is the person at the shop counter who talks to you about the problem, writes up the repair, and coordinates between you and the mechanic. If they do their job well, the shop runs smoothly and customers approve the right repairs.

Term

active listening

Active listening means paying close attention when someone is talking, asking questions to make sure you understand, and not zoning out. In car repair, it helps the shop figure out what’s really going on with the car.

Term

spiffs

Spiffs are bonuses that a worker gets when they sell add-ons or certain services. If someone’s paid that way, they might push extra work even when it’s not really needed.

Topic

service-advisor incentives and upselling

They talk about how some shop staff can get paid in a way that encourages selling extra stuff. The point is to compare that with doing the right repairs and treating customers fairly.

Term

project car

A “project car” is a vehicle being worked on as a hobby or longer-term build, often with parts missing, repairs in progress, or non-standard setups. In the discussion, it’s contrasted with a customer’s car that the shop might not want to take on.

1997 Chevy truck
Car

1997 Chevy truck

They mention a 1997 Chevy truck and say someone wanted brake work done on it. They’re using it to explain why a shop might not want to take certain older cars, even for something that seems simple.

Term

brakes

They’re talking about brake work—repairs or service to help the car stop safely. Even though it’s a common job, the shop might not want to take it if the car doesn’t match their preferences.

Brand

A-OK Auto Repair

A-OK Auto Repair is the name of a local repair shop the speaker trusts. They’re saying it’s better to stick with a mechanic you have a relationship with.

Term

check engine light

The check engine light is a warning on the dashboard. It means the car’s computer noticed something wrong and needs to be checked.

Term

misfire

A misfire is when the engine doesn’t burn fuel correctly in one or more cylinders. It can make the car run rough and may turn on warning lights.

Term

evaporator

The evaporator is a key part of the car’s air-conditioning system. It helps cool the air inside the cabin, and you shouldn’t replace it without confirming it’s actually the problem.

Term

high tide line

The high-side line is one of the A/C hoses that carries high-pressure refrigerant. If it leaks, the A/C can lose charge and start acting up, like not cooling or cycling on and off.

Term

short cycling

Short cycling is when the A/C compressor keeps starting and stopping quickly. That usually means something is wrong, so the system can’t cool the cabin consistently.

Term

superheat

Superheat is a measurement related to how hot the refrigerant is compared to when it would boil at that pressure. A/C techs use it to figure out if the system is getting the right refrigerant flow.

Term

subcooling

Subcooling is another refrigerant temperature measurement that helps A/C technicians check whether the system has the right charge. It’s basically telling you how “cool” the liquid refrigerant is compared to what it should be.

Holden Caprice
Car

Holden Caprice

The Holden Caprice is a large, comfortable sedan made for everyday driving. Like many older cars, it can develop problems with the air conditioning over time. If the AC isn’t cooling properly, it usually needs diagnosis of parts like the compressor, refrigerant level, or related sensors.

Chevy Caprice
Car

Chevy Caprice

They’re talking about an older Chevrolet Caprice they worked on before. It’s just an example of a past A/C problem that taught them what to expect.

Term

PCM

PCM means the car’s main computer for the engine/drivetrain. They’re saying the A/C issue was tied to the computer not turning the compressor on.

Term

compressor

The A/C compressor is the part that “moves” the refrigerant through the air-conditioning system. If it doesn’t run when it should, the A/C won’t cool properly.

Term

ABS light

The ABS light is a warning on your dashboard for the car’s anti-lock brakes. If it comes on, the anti-lock feature might not work correctly, especially during hard stops.

Term

traction control light

The traction control light warns that the traction control system has detected a problem. Traction control helps reduce wheel spin by adjusting engine power and/or braking when the car senses slipping.

Term

diagnostic trouble code

A diagnostic trouble code is a number your car stores when it detects a problem. A scan tool reads those codes so you can figure out what’s wrong instead of guessing.

Volkswagen
Car

Volkswagen

Volkswagen is a European car brand. Here it’s mentioned because the speaker’s experience with European cars affects how they approach diagnostics and repairs.

Term

VCDS

VCDS is a computer program used to diagnose certain European cars, especially Volkswagen Group models. It helps a mechanic read error codes and check what the car is doing in real time.

Term

readiness monitors

Readiness monitors are the car’s own emissions self-checks. If they’re not “ready,” an inspection may fail even if the problem seems fixed.

Term

value blocks

Value blocks are organized screens of live data from the car’s sensors. A mechanic uses them to see what’s happening inside the engine and emissions systems while diagnosing a problem.

Term

diagnostic (diag)

In this context, “diag” refers to paid diagnostic work: using scan tools and testing to identify the root cause of a fault. The hosts describe how multiple complex diagnostics can overlap and slow shop throughput even when the work is billed.

Term

gross profit per unit

This is a way to measure how much profit the shop makes for each hour of work. It helps decide which jobs are worth prioritizing.

Term

PO420 fault

PO420 is a computer error code that usually points to a problem with how well the catalytic converter is working. But the converter isn’t always the real cause, so you still have to check other things.

Term

catalytic converter

The catalytic converter is an emissions part in the exhaust. It helps clean up the car’s exhaust gases, and when it’s not working right it can cause warning lights—though the problem might not always be the converter itself.

Term

PO430 fault

PO430 is a computer error code that usually suggests the catalytic converter isn’t doing its job. It doesn’t automatically mean the converter must be replaced—diagnostics are still needed.

Term

fault code

A fault code is an error message stored in the car’s computer. It tells the shop what system might be having trouble, but you still need to confirm the exact cause.

Term

scan tool

A scan tool is a gadget that connects to the car’s computer. It can pull up error codes so the shop knows what’s actually wrong instead of guessing.

Term

smoke an exhaust

This means using smoke to find leaks in the exhaust. If exhaust is leaking, it can confuse the car’s computer and lead to wrong conclusions.

Term

broken hose

A hose is a flexible tube that carries fluids or air. If it breaks, the car can lose coolant or pressure, and the repair can take longer than expected.

Chevrolet Silverado
Car

Chevrolet Silverado

The Chevrolet Silverado is a popular pickup truck. If the transmission has a problem, it’s a major repair, and the shop has to stand behind the work—especially if the customer is difficult.

Term

transmission

The transmission is what helps the car shift gears. If it’s not working, the car can’t drive properly, and the repair is usually expensive and complicated.

Term

camshaft goes flat

“Camshaft goes flat” is a shorthand for camshaft wear or damage that ruins the cam profile (the lobes that actuate valves). In practical terms, it can cause poor engine timing/valvetrain operation and may appear soon after another major repair, creating blame and warranty disputes.

Master Tech
Car

Master Tech

In the quote you provided, “Master” sounds like it’s talking about a very experienced mechanic, not a specific car. Without the actual car name, there’s no way to explain what that vehicle is. If you tell me the full car name that was meant, I can explain it clearly.

Term

flat rate

Flat rate means you get paid a set amount for a repair job, not for the time it takes. That can make some techs focus on speed, because finishing quickly can mean more pay.

Term

lab scope

A lab scope is a diagnostic tool that shows electrical signals as graphs. It helps a technician see what a sensor or wiring is doing, even when you can’t tell by looking.

Term

engine stall

An engine stall is when the engine shuts off unexpectedly. It’s often caused by something interrupting the engine’s ability to keep running.

Term

heat soak

Heat soak means the engine compartment stays hot after driving. That lingering heat can change how sensors and parts behave, which can cause problems that come and go.

Term

data interpretation class

Data interpretation means figuring out what the diagnostic readings actually tell you. It’s the step where you decide what the numbers and graphs mean for the problem.

Term

visual inspection

Visual inspection means checking the car by looking closely for obvious problems, like leaks or damaged parts. It’s a first step that can quickly point you toward what to test next.

Term

starter diag

“Starter diag” is short for checking what’s wrong with the starting system. Instead of just replacing the starter, you test to make sure the starter is really the problem.

Term

volt drop connection

A “volt drop connection” is a bad electrical connection that loses voltage when you try to start the car. That voltage loss can stop the starter from getting the power it needs.

Nissan Titan
Car

Nissan Titan

The Nissan Titan is a big pickup truck. In this story, the truck seemed like it had a bad starter, but the real issue was a loose cable connection.

Term

intake manifold

The intake manifold is the engine part that channels air to the cylinders. It can also be a tight area to work around, which makes starter access harder.

Term

due diligence

“Due diligence” means you don’t stop diagnosing just because you’re replacing a part. You keep checking so you fix the real cause, not just the symptom.

Term

shotgun diag

“Shotgun diag” means guessing and replacing parts until the problem goes away. The downside is you might not fix the real cause, and you can waste money and time.

Concept

failure analysis

Failure analysis is figuring out what really caused the problem. Instead of just swapping parts, you check the evidence to find the real reason it failed.

Term

starter stuck

A starter stuck means the starter motor (or its internal mechanism) is mechanically bound and can’t spin freely. In this case it’s described as locked up, which explains the no-click/no-crank symptom even after confirming electrical power and ground.

Term

supply voltage

Supply voltage is the electrical power provided to a circuit or component. When diagnosing a no-start or no-click condition, confirming supply voltage helps determine whether the problem is upstream (power/controls) or inside the component being tested.

Term

power and ground

In automotive diagnostics, checking power and ground means verifying both the positive feed and the return path to complete the circuit. A component can fail to operate if either side is missing, loose, corroded, or has excessive resistance.

Term

tire job

A tire job is any work the shop does with tires, like rotating them or swapping them for the season. Here, they’re saying it’s usually more than just the tire work when the shop is overloaded.

Term

commission-based sales

Commission-based pay means you earn more when you complete more work. So the way you do repairs can be influenced by what helps you hit your earnings targets.

Term

hourly

Hourly pay means you get paid for the hours you work. In this conversation, they’re saying that how you get paid can affect how you handle extra tasks or questions about repairs.

Term

AVR test

An AVR test is a quick check to see if a car battery (and sometimes the charging system) is actually working properly. Shops use it to avoid guessing and to confirm the problem fast.

Term

quality control

Quality control time is the extra time a shop sets aside to double-check the repair after it’s done. If it isn’t paid for, technicians may get squeezed when the verification takes longer than expected.

Term

effective labor rate

Effective labor rate is basically the shop’s real average hourly profit from labor work. If it drops, the shop may struggle to pay bills and keep technicians.

Term

labor gross profit

Labor gross profit is how much money the shop makes from charging for labor after paying the people doing the work. If that number gets squeezed, the shop can’t afford things like raises and bills.

Term

Mitchell time

Mitchell times are the “how long it should take” estimates that many repair shops use to price jobs. If a job pays based on those times, it helps the shop standardize labor charges.

Cadillac ELR
Car

Cadillac ELR

The Cadillac ELR is a luxury car that can run using electricity and also has a gas engine. It’s made to help you drive on electricity for a while, then use gas when you need more range. Because it uses both systems, it can sometimes be more expensive or complicated to maintain than a regular gas car.

Term

timing belt

The timing belt is a belt that helps the engine’s moving parts open and close at the right times. It wears out over time, so mechanics replace it to prevent problems.

Car

Honda V6 timing belt

A timing belt is a belt inside the engine that keeps the camshaft and crankshaft working in sync. If it’s not replaced on time, the engine timing can get off, which can cause serious damage.

Part

water pump

The water pump moves coolant through the engine so it doesn’t overheat. Since it’s often hard to reach during a timing-belt job, shops may do it together to save labor later.

Part

idlers and pulleys

Idler and pulley parts guide the timing belt and keep it tight enough to work correctly. If they’re worn out, the belt can wear faster or run out of alignment.

Term

caliper

A caliper is part of the braking system that clamps the brake pads onto the rotor. If it’s put back together without tightening the bolts properly, the brakes may not work safely.

Term

torquing head bolts

Torquing bolts means tightening them to the exact tightness spec. That matters because too loose can be dangerous, and too tight can damage the bolts or parts.

Term

Loctited

They’re using a special glue on the bolt threads so the bolt doesn’t loosen over time. It’s meant to keep things tight even with vibration from driving.

Term

torqued

They tighten bolts to a specific tightness level using a torque wrench. That helps make sure the bolt is secure without being too tight.

Term

brake jobs

A “brake job” is when a shop services or replaces parts in your braking system. They’re talking about how detailed the job should be.

Term

wire wheel

A wire wheel is a spinning brush that scrubs metal clean. Mechanics use it to remove rust and buildup before putting parts back together.

Term

rotor

The rotor is the metal disc the brake pads squeeze against to stop the car. If it’s not handled and cleaned properly, braking can feel worse or wear parts faster.

Term

pads

Brake pads are the parts that press against the rotor to create stopping power. If they’re installed without proper prep, braking performance and wear can suffer.

Term

labor GP

“Labor GP” is basically the shop’s profit from labor work. They’re saying the way the shop tracks profit can pressure techs to rush jobs instead of doing extra steps.

Term

clutch coil

A clutch coil is an electrical part that helps control when the clutch engages. If it fails, the clutch can stop working correctly.

Term

open circuit

An open circuit is basically a broken electrical connection. No electricity can get through, so the part it controls won’t work.

Term

control head

A control head is the part you interact with to control a system in the car. The speaker is saying that on some Nissans, the problem can involve that control unit too.

Concept

can of worms

They mean that once you start down a certain diagnostic path, it can turn into a messy problem with lots of complications. It’s hard to know what’s causing what at first.

Term

production based car

Production-based pay means you’re paid based on how much work you get done, not just how many hours you’re there. If things slow down, your pay can be affected.

Term

crank shaft

The crankshaft is a major engine part that turns the engine’s motion into rotation. If the crankshaft is different for automatic vs manual versions, the wrong part won’t fit or work correctly.

Volkswagen Passat
Car

Volkswagen Passat

A Volkswagen Passat is a common car model. The important takeaway here is that some engine parts can be different depending on whether the car has an automatic or a manual transmission, so ordering the wrong one causes big delays.

Term

automatic or manual

Automatic and manual are two different ways the car changes gears. Some parts can be different between them, so you can’t always swap components without checking compatibility.

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