Why Does the Car Shake More as It Gets Hotter?

[LandonAnn]

The reasons why the car shakes more as it gets hotter are as follows: Intake system malfunction: When the throttle or intake passage has excessive impurities or the air filter element is clogged, the idle passage area becomes too small, preventing complete air delivery to the cylinders. When the air volume in the cylinders is lower than normal, the mixture concentration becomes too high, leading to incomplete combustion in the cylinders, which causes the engine to shake at idle. Ignition system malfunction: Issues with the spark plugs in the car. The function of the spark plugs is to conduct high-voltage electricity into the engine's combustion chamber and generate an electric spark to ignite the combustible mixture. If the spark plugs have excessive carbon buildup, the combustion of the mixture will be poor, resulting in uneven engine power or engine shaking.

[DelXavier]

The hotter the car, the more it shakes. I've encountered this issue several times. After the engine heats up, the shaking becomes more noticeable, possibly due to uneven expansion of internal parts caused by thermal expansion and contraction. For example, there is originally a gap between the piston and the cylinder wall. When the temperature rises, the metal expands, increasing friction and causing roughness. Another common issue is the ignition system. When spark plugs age, the gap increases at high temperatures, leading to inaccurate ignition timing and weak sparks that fail to ignite the air-fuel mixture promptly, resulting in engine tremors. Additionally, insufficient engine oil or coolant can accelerate engine overheating in hot weather, and inadequate cooling can lead to component deformation, affecting balance. When dealing with this, first check the dashboard warning lights. If nothing seems abnormal, measure the engine oil and coolant levels to ensure they're not too low. If the problem is severe, tow it to a repair shop—don't wait until it breaks down on the road. Regular maintenance, such as replacing spark plugs and filters, can help reduce such issues during normal driving.

[MacGideon]

I drive an old car that shakes badly when it gets hot in the summer. The main culprit is the ignition system. When the temperature rises, the performance of the coil or spark plugs deteriorates, leading to unstable high-voltage ignition. The aging of the ignition coil or distributor causes increased resistance when hot, resulting in significant voltage fluctuations and inaccurate ignition, which triggers knocking. Additionally, the intake system is affected as hot air contains less oxygen, making the air-fuel mixture richer and leading to incomplete combustion. Another possibility is the fuel system, where clogged fuel injectors are more prone to blockage as impurities melt in high temperatures, causing unstable fuel pressure. The solution is to check after the car has cooled down. If the car doesn't shake when cold but does when hot, it's a heat-related issue. It's recommended to first replace the spark plugs and clean the intake filter. Prolonged neglect can cause severe engine damage, so it's best to have a professional technician inspect the electrical system as soon as possible.

[SkylarMarie]

My car shakes more after traffic jams or long drives, possibly due to engine overheating causing control module malfunctions. The ECU adjusts fuel supply and ignition based on sensor signals, but thermal deformation affects sensing accuracy, such as crankshaft position sensor misalignment misreading rotation angles. When the oxygen sensor is hot, signal delays cause incorrect fuel mixture ratios and poor combustion. Changes in compression ratio and loose piston-connecting rod connections lead to significant thermal expansion. A simple solution is to park and turn on the AC to cool it down. If severe, get it checked to prevent further damage.