Mechanic warns these five DIY car errors could ruin your ride and your bank

Published on Nov 11, 2025 at 4:33 PM (UTC+4)
by Henry Kelsall

Last updated on Nov 11, 2025 at 4:33 PM (UTC+4)
Edited by Emma Matthews

A mechanic has warned of the five DIY car repair errors that could cost you thousands, as well as your ride.

Many of us probably do, or want to, perform repairs on our cars ourselves, which potentially can save a bit of money versus going to a garage.

But there are some jobs best left to the professionals, especially as DIY car repair errors can cause thousands of dollars’ worth of damage.

Mechanic Chris Pyle recently spoke about some of the worst DIY disasters that could cost customers thousands if they go wrong.

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The worst of the DIY car repair errors

Electrical repair issues are among the worst car repair errors out there, according to Pyle.

They are particularly bad when clients use wire and tape, with the wires often exposed to the weather.

What happens is the wires get exposed to rain and salt, resulting in corrosion and electrical failures.

Pyle said wiring repairs should be done by soldering the wires and then adding heat-shrink tubing to cover them.

An electrical diagnostic could cost up to $150 per hour, not to mention the full repair and labor costs.

Sicking with electrics, incorrectly connected jumper cables or batteries can cause issues.

Doing this wrong can lead to multiple blown fuses, burnt-out wires, and fried modules.

Control modules can cost over $1,000, and repair bills could stretch to $5,000.

Other repairs that could prove costly

A bad installation of the spark plugs is another issue that could see hefty repair price tags.

Cross-threaded plugs or incorrectly torqued plugs are common causes of this.

A thread repair can cost up to $150, but requires removing the cylinder head, which will see the cost rise.

Over-torquing can crack the ceramic insulator or even break the plug off, with repairs costing up to $4,000.

Oil changes can also be costly, especially when it comes to blowouts of old oil filter gaskets.

Engines can be ruined, and replacing an engine is certainly not going to be cheap.

A really big no-no is the use of the wrong and cheap brake pads.

Not only is this dangerous, but they can also fail much faster and cause further damage to the car.

Warped brake rotors and failed calipers could see repair bills of well over $1,000, and maybe more.

Clearing and doing some repairs yourself isn’t the best way to go about things if you’re not an experienced mechanic.

Henry is a content writer with nearly ten years experience, having written for various publications since 2017. Qualifying with a Sports Journalism degree from Staffordshire University, Henry loves all things automotive but has a particular soft spot for classic Japanese cars and anything Lancia. He also has a curious passion for steam locomotives.