What is the general cylinder pressure for cars?
2 Answers
Generally, the cylinder pressure of a car should not be less than seven pressures to be considered within the normal range. The solutions for insufficient cylinder pressure in cars are: 1. First, open the engine and remove the cylinder head to check if the valves are not sealing tightly or if the valve oil seals are faulty, then replace the valve oil seals. 2. If the cylinder friction gap is too large and the wear is within repairable limits, the cylinder liner can be inlaid, followed by cylinder boring. 3. If there is piston ring blow-by, new pistons and piston rings can be replaced. If the issue of insufficient cylinder pressure persists, it is advisable to seek repair at a 4S shop promptly. Additional diagnostic methods for insufficient cylinder pressure include: 1. Unstable engine operation, abnormal noises from the exhaust pipe, or backfiring in the carburetor may indicate insufficient cylinder pressure. 2. Difficulty in cold starts, no significant change in climbing ability, and the ability to manually turn the engine past the top dead center of the piston compression stroke without decompression may suggest insufficient cylinder pressure. 3. Increased oil consumption, exhaust gases coming from the oil filler opening, or even oil spraying out in severe cases may indicate insufficient cylinder pressure. 4. Water droplets exiting the exhaust pipe, carburetor backfiring, and water leakage in or out of the crankcase may suggest insufficient cylinder pressure.
As a guy who frequently works on car repairs, I always tell car owners when checking engine compression pressure that normal gasoline engines usually have a cylinder pressure around 120 to 180 psi, which is based on most engine designs. For diesel engines, it's higher, typically between 300 to 500 psi. Why is this important? Because both low and high cylinder pressure are problematic. Low pressure might indicate worn rings, valve leaks, or other issues, leading to hard starts or lack of power. High pressure could mean foreign objects in the cylinder or abnormal combustion. When using a compression tester, make sure the engine is warm, and the pressure difference between cylinders shouldn’t exceed 15%, otherwise, it's time for repairs. Remember, regular checks can catch issues early—don’t wait until you’re stranded on the road to regret it. The set of tools I use now is straightforward and easy to understand, even beginners can give it a try, but those unfamiliar should seek help from a professional shop.
