Should the exhaust valve be tightened?

[StBarrett]

It is better to tighten the automatic exhaust valve on the car. Here is some knowledge about the exhaust valve: About the exhaust valve: It is better to tighten the automatic exhaust valve on the car, generally more than two turns. After the automatic exhaust valve device is installed, the nut must be loosened to exhaust, but do not unscrew it completely. When gas escapes in the system, the gas will rise along the pipeline and eventually gather at the highest point of the system. The automatic exhaust valve is usually installed at the highest point of the system. When gas enters the exhaust valve chamber and gathers in the upper part of the exhaust valve, as the gas inside the valve increases, the pressure rises. When the gas pressure exceeds the system pressure, the gas will cause the water level in the chamber to drop, and the float will descend with the water level, opening the exhaust port. After the gas is completely discharged, the water level rises, and the float also rises, closing the exhaust port. Similarly, when negative pressure is generated in the system, the water level in the valve chamber drops.

[DeJosiah]

I've been working in auto repair for nearly twenty years, and the exhaust valve definitely needs to be tightened! If it's loose, high-temperature exhaust gases will leak out. Not only will you hear a hissing sound, but over time, nearby wires and plastic components will get burned. Just last week, a car owner complained about a constant burnt smell in the car. Upon inspection, we found two bolts on the exhaust manifold were loose, and the exhaust had melted the oxygen sensor wiring. Jobs like this must be tightened to the torque specifications in the repair manual. It's best to use a torque wrench to measure—don't just rely on feel. For cars that cool down quickly, overtightening might strip the threads, but it's better to err on the side of tightness than looseness—after all, a leaking exhaust pipe is like a water pipe with a hole; the entire exhaust efficiency will drop. During every maintenance session, I remind my apprentices to double-check all bolts in the exhaust system with a torque wrench.

[MacSimon]

Pay special attention to the valve screws when modifying the exhaust pipe! Last time, my friend replaced the mid-pipe himself, but the exhaust valve wasn't tightened properly. Just two blocks down the road, the whole cabin was shaking like a tractor, and a smell of exhaust fumes drifted in. It only quieted down after going back to tighten it properly. The principle is actually simple: all connections in the exhaust system must be tightly sealed, otherwise the exhaust pressure will make the gaps grow larger. Especially for moving parts like valves, slightly loose screws can easily cause leaks. Increased fuel consumption is a minor issue, but exhaust fumes flowing back into the cabin is truly dangerous. I saw a post on a forum where loose valve screws had blackened the heat shield. So whether it's OEM or aftermarket parts, make sure to tighten valve screws firmly until they won't budge. It's best to check for air leaks by feeling around before driving.

[StSavannah]

During vehicle annual inspections, it's common to encounter cars with exhaust leaks, mostly due to loose valve screws. The exhaust valve position constantly vibrates, so it's no surprise that screws naturally loosen. Just think about it - engine exhaust gases reach temperatures of 400-500 degrees Celsius and are corrosive. If not tightened properly and leaking through gaps, not only will the exhaust pipe joints rust quickly, but rubber components on the chassis will also age faster. Last week during an inspection, we encountered a case: the owner complained about poor acceleration, and after testing, the exhaust emissions were three times over the limit. Only when the car was lifted did we discover two valve mounting bolts had fallen out, with gas spraying straight from the threaded holes. That's why special attention is needed during routine maintenance. It's best to tighten the exhaust valve screws every time you change the oil - just wear gloves to protect against burns.