Nissan Repair: oil leaking from tailpipe, timing chain replacement, valve seals

Question
We have a 1998 nissan frontier.  Recently the timing chain went out.  We paid $1700.00 to rebuild the engine.  When we got it back the truck was leaking a pretty decent amount of oil from the tail pipe.  They took it back and said they had sent it back to the machine shop.  two weeks later the truck was returned and is now leaking even more oil out the tail pipe.  The mechanics new diagnosis is that it must be the lower end of the engine.  Is this right? What are some questions I could ask to figure out if we're just getting the screws put to us?

Answer
Hi Sarah -

Not only the screws, but the hammer as well!

My take on this is simple. Truck was running fine before the repair. Now the oil is in the exhaust. They should fix it. Period. Especially at that price.

Anyway, to answer your question, the only way oil can penetrate into the cylinders is through the valve seals, or oil ports in the head gasket, all upper part of the engine (cylinder head). One of them must have been disturbed during the timing chain replacement. Whether it was intentional or not, in my opinion, the responsibility lies with the person or entity that repaired the vehicle.

Questions you can ask - (and please get back to me with their answers) - Did they remove or loosen the cylinder head(s) for any reason? Ask that they take a compression test and report the results to you.

hope this helps -
aloha
calvin