Each screw on the car has a standard torque, and the standard operation for disassembling and installing screws should use a torque wrench. The regular maintenance we often do involves changing the oil, the oil pan screws have standard torque, and tire disassembly and tire screws also have standard torque. These two screws are the most frequently disassembled and assembled screws in the entire car, but few maintenance technicians use torque wrenches to tighten them. They are all tightened with ordinary wrenches, and the magnitude of the torque will definitely differ from the standard. Many cars have broken oil pan screws and tire screws after changing the oil a few times. This is not caused by frequent disassembly, but by not using a torque wrench during tightening and applying too much force.

Why do maintenance technicians not like to use torque wrenches? There are three reasons. Firstly, I have extensive experience and have a relatively accurate grasp of torque. I also know how much force is needed to tighten this screw, and after tightening, it is almost the same as the standard torque. The second is the lazy approach, which is more troublesome to tighten with a torque wrench, and the screws need to be adjusted every time they are tightened. Thirdly, even if most screws do not meet the standard torque, the impact is not significant and will not affect the use of the car.

      What harm is there if the standard torque is not followed every time over time? Taking the oil pan screws as an example, if the torque is too small, there may be oil leakage. If the torque is too high, the screw will be stretched and eventually oil will seep, and even the screw may break. More seriously, it will also damage the screw ring, not only by replacing the screws, but also by re threading the oil pan, which requires a relatively large amount of work. In fact, when tightening the oil pan screws, the vast majority of people will exceed the standard torque, which means they are tightened too tightly, and even the next disassembly is not easy to remove. Some of them are simply dismantled and damaged, which is caused by the last time they were tightened too tightly. The torque of the oil pan screw is about 20-30 Nm, just tighten it with a small amount of force. The same goes for tire screws. Many tire screws that break or cannot be removed are caused by too much force used during the last tightening. No matter where the screws are, as long as they are not tightened with a torque wrench, most of them will be tightened too tightly, exceeding the standard torque.

Key parts must use torque wrenches, such as cylinder head screws and large and small tile screws. There are also common valve cover screws, and many car valve cover gaskets are prone to oil leakage. Replacement requires disassembling the valve cover. Due to the large number of screws on the cover, if a torque wrench is not used, the torque of each screw will be different, some are tight and some are loose, which will shorten the service life of the valve gasket and cause oil leakage after not using it for a long time. Whether it's a repair shop or a 4S dealership, non-standard operations can occur. Car owners can remind them when they see them to save trouble in the future.

From: WONDEE Autoparts

2023-12-5