I think it would take about 8 to 10 hours to replace. this can be checked against a 'shop labor guide' (chilton is one). So the cost of replacement would be reasonable at about $500 to $800. Assuming no other work is required; ie milling & rebuilding the heads. At 70,000 miles , I do not think that would have been needed.
Now as far as the blown motor; there many things that might have happen and not be the fault of the mechanic. So I suggest having another shop or mechanic look at the engine as to why it blowed. If it was the fault of the 1st shop, they are not going to admit it.
If the head gasket was blown because of over heating, I suspect the head was also cracked and the shop didn't repair it. Two other problems that might be the fault of the repair shop which may have cause the engine to blow is:
- improper installation of the gasket; cutting off proper flow of coolant or oil into the head (some gaskets can be installed upside down & look right);
- improper installation of the lifters & push rods. These can damage a valve and allow it to drop into the cylinder; ie, blown engine. Removing the valve covers & inspecting will determine this.
Get prices from other shops to repair/replace the engine. At the same time the mechanic can remove the head and tell what caused the engine to fail. ... At 70,000 miles (low mileage engine), I think the problem might have been cause by the first mechanic. If the problem was not the fault of the 1sr shop, then the heads should still be in good working order and no problems.
<message edited by edwmax on Wed, 12/28/11 9:33 AM>