* Valve Train Issues: This is a very likely culprit. The clanking could be caused by:
* Worn rocker arms or lifters: These components are crucial for opening and closing valves. Wear can lead to noisy operation, poor valve timing, and eventually engine damage.
* Broken rocker arm: A completely broken rocker arm will produce a loud, distinct clanging sound.
* Valve lash adjustment: If the valve lash (clearance) is incorrect, it can create a clattering sound. This is less likely to cause hard starting, though.
* Timing Chain/Belt Issues: While less likely to be solely *upper* engine noise, a worn or failing timing chain or belt (depending on the engine) can cause a clanking sound and seriously affect starting and running. A broken timing chain will result in catastrophic engine damage.
* Connecting Rod Issues (Less Likely but Serious): Although you specify an "upper" engine noise, a severely worn or damaged connecting rod *could* manifest as an upper-end clanking sound if the damage is affecting piston movement and leading to piston slap. This is a much more serious and costly repair.
* Loose or Broken Component: Something relatively minor, like a loose heat shield or a bolt that has come loose, *could* be making the noise. However, this is less likely to explain the starting and running issues.
Why Hard Starting and Stalling?
The starting and running issues are likely related to the clanking noise, potentially stemming from:
* Poor valve timing: Damaged lifters or a timing chain problem can result in incorrect valve timing, making it difficult to start and keep the engine running.
* Low compression: Worn components in the valve train can lead to low compression, making starting harder.
* Ignition problems (less likely, but possible): While less likely to directly cause the clanking, ignition issues *could* exacerbate starting difficulties.
What to Do:
* Do NOT continue to drive the car. Driving with these symptoms risks serious engine damage.
* Have a qualified mechanic diagnose the problem. This is not something you should attempt to fix yourself unless you are experienced in engine repair. The mechanic will need to listen to the noise, perform a compression test, and likely inspect the valve train and timing components. Ignoring this could lead to a significantly more expensive repair later.
The clanking noise is a serious warning sign. Prompt professional attention is necessary to prevent catastrophic engine failure.
