How to Distinguish Intake and Exhaust Valve Springs?
2 Answers
Valve springs with five dots are for intake, while those with three dots are for exhaust. The rocker arm's larger wheel is for exhaust, and the smaller wheel is for intake. Longer valve springs are for intake, and shorter ones are for exhaust.
In my experience with DIY car maintenance, distinguishing between intake and exhaust valve springs isn't really necessary because most regular vehicles use the same springs - the valve spring design is universal for both intake and exhaust valves. In an engine, the valve spring's job is to make the valve snap back quickly. When you open the cover to inspect, they're installed in different positions: intake valve springs are usually near the intake port, while exhaust valve springs are closer to the exhaust pipe. If you must differentiate, exhaust valve springs might be slightly stiffer because they need to withstand higher temperatures from the exhaust pipe, so the material may be more heat-resistant. But for regular family cars, there's hardly any noticeable difference. Last time I replaced springs, I just followed the manual without bothering to distinguish them. Remember, improper disassembly can affect sealing or cause air leaks, so it's best to test the engine's operation before repairs or simply take it to a professional shop - saving you from costly repairs if something goes wrong.
