How to diagnose problems with your car

How to diagnose problems with your car

So you've blown up your car. It happens to the best of us, and the first step (after sitting down and crying) is to work out what has actually gone wrong so you can repair it and fix whatever failed in the first place, just as the lads did with their 3 BROKEN CARS IN THE LATEST EPISODE. Obviously, only attempt to work out what has gone wrong with your car if you are confident that nothing is unsafe and make sure you have mechanically experienced friends or family members there to help you.


Sometimes the answer to a problem is obvious (like when there are pieces of crankshaft sprayed up and down the front straight), but other times the problem hides and you need to dig deep to work out what broke or went wrong. First things first, work out roughly what area of the car has a problem; engine, suspension, drivetrain (gearbox and diff), or electricals. 

If your car has picked up a random clunking noise or bad vibration, see if it gets worse the faster you go. This often signals there is an issue with the suspension or drivetrain, narrowing down the possibilities and making it easier to diagnose. The next step is to work out which corner of the car has the problem, by seeing if you can hear where the noise is coming from as a friend drives your car in a circle around you at walking pace.


Once you have identified where (roughly) the problem is, it is time to jack up the car and secure it with several weight-rated stands, as well as some safety measures like spare wheels positioned under the sills. You may need to give the car a shake or undo stubborn bolts are part of troubleshooting so extra supports are a must!

Start troubleshooting by checking for loose bolts. Look at the car and how the suspension is designed, and think of what could come loose, or break, and make the noise as you hear it. Does it happen on bumps? Or when you turn left or right? Or does it only happen as you drive faster in a straight line? Try turning the tailshaft and spinning the wheels to see if there is excessive play in any of those areas. 

Look for broken metal, missing parts, or leaking fluid as this can tell you where something has failed, or been knocked off. Sliding under the car and spinning parts will also help understand how the drivetrain and suspension systems work, and this leads to being able to figure out where something might have failed. 

If you have tried looking around the car for where the noise is coming from but you can't pinpoint it (or you're not confident) then seek professional help before you attempt to diagnose the car and just wind up clogging your mum's driveway with an immobile car when she needs to go out and buy your dad new pants after he slipped over in the pool of oil your nugget was leaking into their garage (not that this has ever happened to me). 

Next week we'll have a look at diagnosing engine problems, as we learn about suck, squish, bang, blow (that isn't a party game you played with Janice in Year 9, guys).

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