What causes a loud cold start knock noise?
I don’t think there is anything (maybe a rebuild) that will fix the piston slap. The lifter noise is usually dirt and, or wear, that lets the lifter “bleed down”. Sometimes as @ Conlan Rose suggested, it might be a slow to build oil pressure issue, that is caused by a dirty oil filter, sometimes it’s clogged oil passages.
When does the loud cold start knock go away?
It’s loud enough to have given me pause but it’s gone in 20-30 seconds as oil gets to moving around and the vehicle commences its warm-up. Doing some reading, online, it appears that this is ‘normal’ for 5.3L Vortecs and that it isn’t harmful.
Where does the morning sickness knock come from?
The morning sickness knock can come from two areas (assuming engine wear is normal for the mileage), the lifters and piston slap (as has been suggested). Neither one will hurt the engine, just piss off the owner.
What does it mean when your car makes a knocking sound?
A knocking sound from your car’s engine is never a good sign. In fact, it almost always means you have a serious (and costly) problem on your hands. A low oil level can cause engine knocking. If you get lucky, the noise may subside when you refill the engine with oil.
Where does the knocking sound come from when decreasing speed?
The knocking sound appears to be coming from the driver’s side while decreasing speed at stops on straight roads. My car has 135000 miles. My car has an automatic transmission.
What causes loud noises in the middle of the night?
You might even think a gunshot or car crash has occurred outside your bedroom and get up to check it out. Sudden loud noises around sleep transitions may also occur as part of a condition called exploding head syndrome. What is exploding head syndrome?
Do you hear a knocking noise while backing up?
Attempt to replicate the noise while backing up. If the brakes are of a concern, you will likely hear it in both directions. Something like your drive shaft may not be heard while backing up. Most of these components can be tested while on the vehicle, but you may need a hand.