The valves get damaged rarely, just do the chain, then do a compression test. Was this a high speed event where the chain broke? That might cause valve damage.

Once again, what irrelevant codes? I bet the CEL has been lit for a long time.

 

There is more than one way to check for valve damage. Does the engine crank? Do compression test. If not they should have a bore scope and look inside the cylinders for damage. What kind of shop is this?

 

Bent valves would be a good reason for crank/no start. As a 1st step, I disagree with risking making things worse by cranking it for a compression test.

Borescoping and looking at the top of the cylinder head for evidence of stuck valves could confirm valve damage. If none is found, I suppose you could defend doing the chain job, but what's the explanation for the no start? Being off one tooth isn't it.

 

If it cranks it's not going to hurt anything that was not already hurt. The only way for him to hurt it is if it jumps time while he's cranking it. Any shop that gets a no start will give it a crank. All shops I know do that.

 

I pull the plugs and boroscope the piston tops! Then pull the valve cover and inspect the valves for damage.

 

If the chain is sloppy enough, in particular if the cause of the slop is a failed tensioner ratchet, you risk jumping another tooth every time you engage the starter. Sure, the mechanic is likely to try for himself to start it... unless the customer tells him about the timing codes and asks him not to, and he has the 1st clue about Ecotec chain problems. Then he'll pull the valve cover and look at the chain first. If it's sloppy, there's no point cranking it, and if he does so' he's a fool.

 

If a customer tells us to tear it down we will gladly do that if he signed the work order.

 

Do compression leak test and turn it by hand from one TDC to the next….all 4 cylinders. But you must hold the crankshaft bolt to prevent rotation and it can go either way depending on exact position of the stroke….I would recommend using a lower air pressure for safety reasons ( like 50-60 psi) then if suspect bent valve you increase pressure but understand…..this is dangerous.