I just purchased a non running 1.8t 2006 A4 Cabriolet where the owner said the timing belt had broken. After dismantling I noticed the timing belt was slack but the timing marks on the crankshaft and camshaft still lined up. It looks like the tensioner no longer tensions.
Now here's the $500 question:
Last night I took the head off and there's no sign of any valve contact on the pistons.
I have a recon head waiting to go on, but I'm thinking that maybe I don't need it and I can save $500. How can I tell definitively whether the valves are good? Is a simple visual check that they close properly, good enough?
Anyone have some advice?

Mark

 

One way is to remove the camshafts, which will naturally leave all the valves closed. Now if a solvent such as isopropyl alcohol is poured into the ports, any leaks at the valve seats will become obvious. Minor leaks can be solved by removing valves and using abrasive grinding compound to match the valves and their seats in the head.