Your car shouldn’t be shaking. If it does, there is something wrong with it. However, depending on the kind of the shake and the moment it happens, the cause, fix and seriousness can vary greatly. Here’s a quick guide of what could be wrong depending on when and how your car is shaking.
Car shaking while driving
The tyres could be the source of the problem. They might have bumps and bulges and this is something you should take care of immediately. Basically, if your tyre has bulges, you will need to buy a new one. So the fix is simple, but not always cheap. Still, risking a flat tyre during driving is a very dangerous thing.
Tyres can also be out of balance, or you might need wheel alignment. In these cases you might feel a shake occur at a certain speed and then disappear.
This is very uncommon, but the first thing to check is if the wheel is firmly attached.
Bad wheel bearings can also cause shakes, as can axle problems which can occur more often if your drive on rough roads, or if you have hit a curb roughly.
A problem that is unrelated to wheels is a bad engine mount. These hold your engine in place and if one of them is not as it should be, the heavy and very active engine can make some serious moves.
Engine problems can also cause shakes while on the move. It can be related to low compression, bad air and fuel delivery, or wrong ignition timing and spark plugs. Regardless of which of these issues it is, you will need a good mechanic. The repair cost can vary greatly, from clogged air or fuel filters which are reasonably cheap, to full engine rebuild which can cost more than the car itself.
Car shaking while braking
This is probably due to brake rotors and especially so if your steering wheel also starts shaking when you brake. You can even get the same sensation from the brake pedal.
Car shaking while idling
This can also indicate a problem with the engine mounts. Also, problem with fuel injection can cause serious vibrations while the car is stationary. You will often see that your idle RPMs are irregular if this is so.
Car shaking on steering wheel
Aside from the mentioned thing with the brakes and tyres, steering wheel shakes can indicate any kind of a suspension problem with things like shocks, tie rods, bearings, ball joints, struts…
Car shaking while taking off
This usually comes with a sound as well, although not always. It is probably one of the more expensive issues and it usually means that your transmission or drivetrain have problems.
The issue can also be a bad drive shaft, if your car is RWD. However, you will rarely need to change the entire driveshaft and the fix could be a rather cheap part. Moreover, if you are driving a modern diesel with a dual-mass flywheel, this might also be an issue.
Probably the harshest vibrations come from transmission problems. If you feel very hard shakes during acceleration, you might be running low on transmission fluid. Make sure you visit a mechanic, since this can destroy your gearbox and this is one of the most expensive issues you might have on your car.