At the Mechanic: 6 Car Problems That Are Often Misdiagnosed

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Japanese Tuning Shop | Micah Wright/Autos Cheat
Japanese Tuning Shop | Micah Wright/Autos Cheat

So your precious set of wheels isn’t acting normal, and you’re afraid that if you take it in for some serious surgery the mechanic is going to take full advantage of your mechanical ignorance and ravage your bank account. It’s a scenario that is sadly common for those of us with aging automobiles, and try as we might to keep them ship-shape and running right, Father Time’s ticking hands constantly keep browbeating our cars into smithereens.

But waiting until things get worse is never a sound plan, so you whip into a nearby service station for a quick diagnosis and cold beverage. As you watch the mechanics prod an poke their way around your engine bay, a line of sweat begins to draw across your brow. Questions surrounding what’s causing your car to not work right, how long it will take to replace a compromised component, the agony of paying top dollar for said item, and the puzzled way in which the mechanics are looking at one another all cloud your vision.

After what seems like an eternity the mechanics walk over to you and explain that you need a part that costs hundreds of dollars, and that if ordered today, your car can be ready to roll as early as the next morning. You begrudgingly oblige, and sign off on the notion, because after all they are the ones who are ASE certified technicians, not you.

The next morning you return to pick up your car, and after paying one massive bank account-crippling bill, you’re back on the road with your trusty steed humming along in perfect time. But something’s amiss, and those old symptoms slowly crawl back, and as you pull into your drive, a dreaded thought strikes you like a bolt of lightning: “Did the mechanics replace the wrong part?”

We hate to say it, but even ASE certified technicians occasionally make mistakes, and whether it be intentional or accidental, misdiagnosed automotive maladies are a financial and logistical nightmare that many Americans are subjected to every year. Here are six commonly misdiagnosed automotive issues that mechanics and Consumer Reports alike have noted as top offenders, because nothing says “whoops” quite like replacing a perfectly good part and realizing that the problem still exists.

1. Fuel issues

Injector Dynamics ID1000 | Source: Injector Dynamics
Injector Dynamics ID1000 | Source: Injector Dynamics

Fuel systems are a complex and can be a very temperamental type of of car component, one in which Consumer Reports says can often lead to confusion and misdiagnosis down at the local repair shop. Defective injectors with bad O-rings get blamed for a defunct fuel filter that’s slowly leaking gas out of a hairline crack, or the fuel pump itself seems to act up and you’re told it’s time for a new one when all the car needs is a fresh solenoid. The amount of misdiagnosed fuel issues in the automotive repair biz is fairly widespread, and since a lot of that has to do with high-dollar hourly shop expenses, be cautious of any mechanic that seems overly confident that your issue is a big one if it’s not apparently obvious.

2. Electrical gremlins

Tuck Tech Wiring Harness | Source: Cheddas Auto via Facebook
Tuck Tech Wiring Harness | Cheddas Auto via Facebook

If you think tracking down a guilty culprit in your car’s fuel system was tough, imagine what an electrical fiasco could entail! Modern day technological wonderment aside, the average automobile is a jumbled mess of wires, sensors, computers, solenoids, and switches, and as time goes by some of these elements can grow brittle and can even break on you. Another issue with electrical gremlins few think about is that a short on one end of the vehicle could cause a major issue on the other, which leads to a lot of guess work and is never a good thing. Think we’ve got it bad now? Imagine what will happen in twenty years, when all of these modern, sensor-filled automobiles you see today begin to start showing their age.

3. Air conditioning woes blow

AC Freon Recharge | Source: Facebook/ AC Pro
AC Freon Recharge | Source: AC Pro via Facebook

Too often drivers will get fleeced in the hot summer months, because when your AC system suddenly stops functioning properly, common sense goes out the window, and desperation sets up shop instead. While tossing a fresh can of Freon at the problem or conducting a complete AC system recharge may sound inexpensive and easy, you stand a strong chance of being back in the same hot and bothered state in no time. We suggest avoiding this route, and going to a reputable mechanic that knows their way around an AC instead. If you’ve never had issues before, spending the money on a full leakdown and compression test is often the best way to begin, as this will help you and your mechanic determine exactly wherein the problem lies.

4. Heater/cooling conundrums

Add Antifreeze | Source: PEAK Antifreeze & Motor Oil via Facebook
Add Antifreeze | Source: PEAK Antifreeze & Motor Oil via Facebook

Beware of a mechanic that says you need to flush your motor regularly, even when your vehicle’s manual mandates otherwise. A lot of shops line their wallets by stressing how important it is to flush out a coolant system, when it really doesn’t have to be done all that often. There also can be an honest misdiagnosis based around overheating, where it looks like a water pump or a thermostat are the guilty culprit, when it could be a clogged heater core causing your headaches.

5. 02 sensor misdiagnosis

NGK O2 Sensor | Source: NGK Spark Plugs Malaysia Bhd via Facebook
NGK O2 Sensor | Source: NGK Spark Plugs Malaysia Bhd via Facebook

Is your older car running like complete crap even after swapping in new spark plugs, wires, and new air and fuel filters? A faulty oxygen sensor could be your issue, and depending on how many banks (portholes) your exhaust has, the problem could be a direct trigger response from another sensor. On the other end, a tripped code on a modern car telling you that your O2 sensor is bad could also be nothing more than a vacuum leak, which is typically easier and cheaper to fix.

6. Clunking and squeaking suspension symptoms

Cheddas Auto Rear Lower Control Arms | Micah Wright/Autos Cheat Sheet
Cheddas Auto Rear Lower Control Arms | Micah Wright/Autos Cheat Sheet

All it takes is one bad sway bar end link, and suddenly you’re getting an earful about how you need new struts, springs, lower control arms, and all kinds of suspension fixes. Sure, on a vehicle with 200,000 miles, where very little has ever been done to the undercarriage, we can certainly see the validity of this assessment. But on the average car that’s seen regular repairs and shop visits, the clunking and creaking worn bushing conundrum can easily be a money pit for anyone in the company of a shady mechanic or an individual who isn’t thinking all too clearly.