My dad has a 02 duramax that is going thru coolant like crazy. He said that he can only get about 10-15 miles before he runs out of coolant. The coolant appears to be coming from the back of the motor by the oil pump. Whenever it runs out of coolant it sucks the bottom hose flat. I have did searches on the problem her on the site and have found the problems about the injector cups or head gasket. He says that it isn't smoking at all and doesn't use any coolant at idle only when he revs the motor up. He isn't towing anything with with it.

does the top rad hose stay hard after it has been sitting for a while? and is there any black carbon in the coolant overflow bottle?

Niether

He told me that it is coming from the driver side rear of the motor. Is there a freeze plug there that may have came loose

He told me that it is coming from the driver side rear of the motor. Is there a freeze plug there that may have came loose

Check near the oil filter .. the filter adapter oil cooler assy uses engine coolant to cool the oil ..

http://www.dieselplace.com/forum/attachment.php?attachmentid=98652&stc=1&d=1266278065

have you tried pressure checking the system?

have you tried pressure checking the system?
This would be a good first step.

it is the gascket on the oil cooler/filter housing to the 90 degree cross pipe mine did the same thing they show it in the diagram in the previoushttp://www.dieselplace.com/forum/attachment.php?attachmentid=98652&d=1266278065 post

my dad replaced the gasket on the oil cooler and it fixed the problem. took about three hours and 90 bucks. Thank for all the help.