Engine making very loud noise when started

Check for loose heat shields.

Hi, Please check you engine oil as a first start. A loud noise could indicate engine failure or engine auxiliary components failure. You can know if the sound is tapping or knocking or if the sound is rubbing or grinding sound due to rotation. At time you may have a drive train fault

What's That Ticking Sound Coming From Your Car's Engine?

www.popularmechanics.com/.../whats-that-ticking-sound-coming-from-...

Apr 18, 2014 - My engine has developed a strange ticking sound. Its whisper-quiet before an oil change, and then makes a loud tapping after a new filter and ...

Engine Tapping - Auto Repair Help

www.auto-repair-help.com/auto_diagnostics/engine_tapping.php

ENGINE MAKES TAPPING NOISE WHEN STARTED by Mark Davidson. SYMPTOM SUMMARY The engine emits a tapping noise on start up. The noise may ...

Engine Ticking Clunking Noise - Repair - YouTube

? 9:37
https://www.youtube.com/watch?v=ilDtnJi_BS0
Mar 15, 2013 - Uploaded by knurlgnar24
One of my vehicles started making a rather disturbing sound so I went to investigate and to hopefully fix it.

It sounds as though you may have a starter bendix failing or the starter bolts may have loosened. Disconnect the battery, crawl under and investigate.
If the bolts are tight, you may want to look into the cost of a new starter.

Good luck

Flex plate is cracked. That is another reason it stalls.

sounds like you need to replace the power steering pump,of not overheating or loosing coolant,would check water pump,if no power steering sonds like the pump is bad,mechanic depepnding on their ability could change for you,up to you if you want to pay a shop to replace pump.

you can do it without remove the whole engine reffer those links
http://www.youtube.com/watch?v=dLwahcpsKEM http://www.ehow.com/how_2321779_change-pistons.html

First, make sure the cap is on tight at the fuel tank.

Then, investigate the loud clicking noise in the engine.
Check engine oil level and add as necessary.

If this doesn't solve the problem repost your problem.

engine is pinking,predetonation of fuel or the fuel mixture is weak which can be caused by a vacumn leak on the inlet manifold ,such as the take off for the servo ,or the manifold bolts loose.Also the timing is set wrong which could be a fault with sensor or the sensor drive ring .Without the car in front of me i cannot really diagnose a fault like this ,either get the VW mechanic to have a look and if he thinks its electronic then take it to VW

How long have you ran the engine ? I know that they will run rough and sometimes make strange noises for a few secounds or a little bit untill everything get oiled up again. I would make sure all the push rods are back in the right place and that all the lifters are tight.