A clunking sound upon engine start-up may be caused by several issues, including a loose or damaged engine mount, which can result in excessive movement of the engine. Another potential cause could be a failing starter motor or its gear engaging improperly with the flywheel. Additionally, low oil levels or oil sludge could lead to insufficient lubrication during start-up, causing metal components to make contact and produce a clunking noise. It's advisable to have a mechanic inspect the vehicle to diagnose and resolve the issue.
Valves tapping?
yes and yes
Could be the rocker arms in the engine, change your oil and if you ever get into the engine check those little SOBs out. ;)
A frail fuel line can cause a diesel engine not to start.
Yes, just about any sensor on the engine could cause a no start.Yes, just about any sensor on the engine could cause a no start.
check the solenoid, and the starter.
No engine lube at start up. Bad oil pump or very dirty engine lube passages.
does the sound come from the engine,or the radio???
Yes
a bad engine
engine
most likely your transmission is slipping and usually is the onset of your transmission going