Bearing or exhaust leak?
 

http://www.youtube.com/watch?v=21lT_...ature=youtu.be

Hello,

I have an 88 Turbo. I just recently had the head rebuilt by a reliable shop, and I have driven it less than 500 miles since the rebuild. I started to drive to work Friday and heard this loud knocking sound. This is the only time I have started it since Friday. It seemed to be much more consistent on Friday, not clicking in little triplet bursts like it does in the beginning of the video.

The oil pan is full and the car wasn't driven more than 1/4 of a mile before it was parked and turned off. I checked the spark plugs and cables however I did not remove the spark plugs individually while the car was running to test if the knock gets quieter on a certain cylinder. I have read that it may possibly be an exhaust leak around the manifold but I don't see any improperly aligned or tightened bolts around the manifold.

I guess some car guys can just hear a knock from an exhaust leak right away, I cannot.

Opinions? I am prepared for a rebuild, just not as prepared as I would like to be...

'e = There is also no check engine light and I did not get any smaller clicks or warnings that a bearing wasn't aligned.

Given that you haven't had the bottom end apart there's fair chance that some of the studs in the head pulled loose. It's not common with old aluminum heads supporting very large and heavy exhaust structures... especially a turbo. I'm not going to speculate and definitely not based on a youtube video. Pull the plug wires one at a time. An exhaust leak will also quiet down but it won't go away.

The car has 2 bad bearings. My mechanic told me after the head rebuild that there was some really heavy oil in the engine. The car was likely driven for some time on a blown head gasket and the bearings are shot.

I will be starting my motor rebuild plan now, something I had hoped to put off for about a year while I gathered parts.