Probably a simple question but. .
Thread Starter
Joined: Aug 2005
Posts: 2,803
Likes: 1
From: Seminole County, Florida
Probably a simple question but. . Why is a motor louder when you cold start it.
And im not talking about before it finds idle. Even when my car finds idle its louder cold than all nice a hot
And im not talking about before it finds idle. Even when my car finds idle its louder cold than all nice a hot
I think he means internal noise, not the noises associated with combustion.
The answer is that the engine has to build oil pressure, and pump it up to the top of the engine, all while the oil is as cold as it is outside. Thus it is much thicker, moves slower, doesn't slide into tight gaps, etc. Because of this, your engine will make more noise, usually lifter/valve actuation noise and lower end bearing noise, on start up. This shouldn't be much of a consideration on small block Chevy's, their oiling system is pretty well sorted out by now. But my 3.4l DOHC V6 for example is very noisy on cold starts, specifically in the lifter areas.
The answer is that the engine has to build oil pressure, and pump it up to the top of the engine, all while the oil is as cold as it is outside. Thus it is much thicker, moves slower, doesn't slide into tight gaps, etc. Because of this, your engine will make more noise, usually lifter/valve actuation noise and lower end bearing noise, on start up. This shouldn't be much of a consideration on small block Chevy's, their oiling system is pretty well sorted out by now. But my 3.4l DOHC V6 for example is very noisy on cold starts, specifically in the lifter areas.
It's because the exhaust is colder and the sound waves travel and reinforce each other differently.
This happens no matter what the idle speed and no matter fuel-injected or carbureted... as in the same amount of air being consumed by the engine in the case of a carburetor.
This happens no matter what the idle speed and no matter fuel-injected or carbureted... as in the same amount of air being consumed by the engine in the case of a carburetor.
