Rick's Free Auto Repair Advice

Bring parts to mechanic

Bring parts to mechanic? Why shops won’t install customer parts

Can you save money by bringing your own parts to the mechanic?

Auto repair shops, just like every other service business, make their money on labor profit and parts profit. When you bring your own parts because you found them cheaper online, you’re basically asking the shop to forfeit some profit. Let’s look at why that doesn’t work.

Reason #1 Why most shops won’t install your parts

We’ll talk about the profit issue later. But first let’s tackle the practical side. Penny pinching customers quite often buy the wrong part or the cheapest part they can find. Those low quality parts often don’t come with new fasteners or associated parts like gaskets, belts or sealants.

The shop quotes a price, removes the old part and then finds that the your part is wrong, doesn’t fit properly or is missing fasteners or associated parts. So you run back to the auto parts store to exchange the part and round up the missing parts.

In the meantime, the shop’s bay is tied up and the clock is ticking. A tied up bay is lost money. That’s a huge deal for a small shop. If the shop bills you for the extra time involved, you’ll scream bloody murder and give the shop a bad online review.

If, on the other hand, the repair goes well but the cheap part fails early, you’ll immediately blame the shop for messing up the installation and give the shop a bad online review. Either way, the shop gets screwed and has to deal with bad online reviews; all while losing profit on the repair.

Customer provided parts cause nothing but aggravation for shops

Reason #2 why shops won’t install your parts — they lose money on you

Shops make their living on labor profit and parts profit. Just like every other service business, shops buy parts locally and mark up the price to the customer. That’s standard in every single service business. Plumbers, electricians, HVAC installers, and carpenters all buy the parts and all service businesses add a parts markup.
Parts markup varies in the auto repair but generally runs 66% to 100%.

How does the part markup in the auto repair business compare to other service business?

Let’s take a look at the HVAC and plumbing industries.

Parts markup on a new furnace

In 2022 the typical installed price for for a baseline 60,000 Btu furnace and 2-ton AC unit is around $8,900. The company’s cost for the furnace, evaporator coil, condensing unit, refrigerant, tubing, sheet metal, piping and city permit averages about $3,300. It takes two workers about 12 man-hours to remove the old furnace and install the new setup.
• 12 hours @ $125/hr =$1,500 – actual fully loaded hourly cost of $55/hr ($660) for a labor profit of $840 (97% markup on labor).
• Salesperson’s commission @ 10%= $890
$8,900 selling price minus $1,500 labor, $890 sales commission, and $3,300 parts cost =  $3,210. $3,210 ÷ $3,300 = 97%

So the labor markup is 97% and the parts markup is 97%

Parts markup in the plumbing industry

You hire a plumber to a new 50-gallon atmospheric water heater. The going rate for a water heater installation in 2022 is around $1,800. The plumber’s cost on the water heater and supplies and permit is about $700. It takes about 1.5 hrs to install (1.5 hrs X $150/hr= $225. $225 labor plus parts, supplies and permit = $925. $1,800  – $975 = $875.

So the plumber marked up the water heater by 125%.

Bottom line: if you bring your own parts, the shop loses money on you. Why would they do that?

Reason #3 — the markup isn’t all profit

The cost to price and order parts

The shop has costs associated with supplying the parts. It takes time to price the parts in order build the estimate. It takes time to order the parts. It takes clerical time to pay the parts suppliers at the end of each month. That labor isn’t free.

The costs of providing a warranty

Most shops provide a warranty on the part that includes the labor to replace it if it fails within the warranty period. Sure, the parts store will issue a free replacement  if the part fails within the warranty period. But the shop has to eat the cost of the labor. Somebody has to account for that cost somewhere; it isn’t free. So a portion of parts markup goes to cover warranty work.

Ok, you found the parts much cheaper online. So what?

If you’re comparing the price of auto parts online to the retail price from your local shop and you think your  “mechanic is ripping you off; well, you’ve got a lot to learn about how a business works.

But Shops don’t buy parts online

When a shop needs a part, they pick up the phone and call a local parts supplier. Why? Because your vehicle is sitting in their bay and time is money.

Lets say your car needs a new AC compressor. You found a Four Seasons brand for you 2014 Subaru Outback on Rockauto for $371.79. But the shop is quoting you $1,191.98 for a Four Seasons compressor (the exact same part you found online). You found the same part at your local Autozone for $744.99 and you think they’re ripping you off. They’re not.

They’re buying it from the local AutoZone for $744.99 minus a trade discount of 20% ($744.99 x 80% = $595.92). Then they’re adding their 100% markup ($595.92 X 100% = $1,191.98. In other words, it doesn’t matter what you can pay for the part online because shops don’t buy their parts there. And it doesn’t matter what you can buy the part for locally, because that part price doesn’t include the shop’s markup.

What about the shops they will install the parts you bring to the mechanic?

In most cases, they’ll either up their normal hourly rate or they’ll adjust the quote upwards to compensate for the lost parts profit. Either way, they’re not going to lose money on you. Why should they?

Finally, without a parts profit, no shop will give you a warranty.

©, 2018 Rick Muscoplat

Posted on by Rick Muscoplat

Custom Wordpress Website created by Wizzy Wig Web Design, Minneapolis MN