It is usually a worn timing chain or chain guides, the noise disappears as the oil pressure expands the hydraulic chain tensioner. Or it could be gummed up, or worn, hydraulic tappets/lifters; or piston slap from worn pistons/cylinders; worn bearings – many things. If it is a diesel – it’s normal.
Why does my car make a rattling noise when I first start it?
If you hear a “clack-clack” kind of rattle when you start your car’s engine, it could be a sign of piston slap. Pistons move up and down in their cylinders with a tight fit between the piston and cylinder wall.
Why does my engine sound loud when I start it?
So, what is that grinding noise you hear when starting a car? Most likely, if it is true grinding that you hear, the problem is related to the starter. Causes include the starter not lining up correctly with the ring gear on the flywheel, missing or damaged gear teeth, or a faulty solenoid.
Why is my car making noise when I start it and the noise goes away after a few minutes?
This is usually due to the bearing on the pulley for one of these beginning to go bad, and so it makes noise during startup that will usually go away once oil circulates or the bearings heat up and expand slightly, making the operation smoother and quieter.
Why does my engine rattle on a cold start?
A rattling noise on a cold start is caused by two things – an oil problem and a break or tear of the variable valve actuator O-ring seal. It’s not normal for your car to make a rattling noise during regular driving because this means there is something wrong with the internal parts of your engine.
Why does my exhaust rattle when cold start?
They said its common to have that noise cause not enough vaccum pressure goes into the exhaust at a cold start to regulate the system that makes it a dual exhaust during hard acceleration.
How do you fix a cold start rattle?
Now if you think about it you have to remove both valve covers and the timing side of the engine in order to access this variable valve timing gear.
Should a timing chain rattle on startup?
The reason timing chains can be noisy on start up is either the pressure in the oil charged tensioner is bleeding off, or there is extra slop in the chain system that the tensioner isn’t design to take up. Dirty oil can lodge debris in the tensioner that will keep the check valve open bleeding off oil pressure.