My aurora has been running hotter than normal and I have noticed a gurgling sound from the passenger side when I step on the gas or accererate. The temperature gage tends to read really hot after starting it up after a quick stop like filling up at a gas station. After driving it around a it will cool down a bit.

Any ideas what it could be? water pump? thermostat? head gasket?

Gurgling on acceleration, is not a good sign. I'd do a 'block check' test for combustion gases in the coolant. A positive test would indicate a head gasket problem, probably due to loose head bolts. With an overheating Aurora, it's best to start at the worst case, and work your way down. Saves money, time, and aggravation.

I started it up and opened up the coolant resavor and smelt exaust.

Are loose head bolts an easy thing to take care of?

Would head gasket stop leak work?

Loose head bolts are a common Northstar engine problem but also a very expensive repair no matter who you get to do it. The entire engine must be removed, both heads removed, and the head gasket replaced. All head bolts must then be replaced along with Timesert inserts only! This is very important, as timeserts are the proven way to fix this. Threads in the Northstar's aluminum block sometimes shear off, resulting in loosened head bolts.

To confirm this as your problem a block check test should be done by your mechanic. A do it yourself kit is available from NAPA auto stores for around $50.00. Once you are sure this is the problem, an experienced 'heavy-line' (engines and transmissions only), Cadillac technician is your best bet for this job. If you prefer an independent shop, you should make sure they are knowledgeable in the Northstar engine! Depending on the cost of labor, the job can take around 20 hrs or more plus parts. You're looking at anywhere from 2000.00 to 3000.00 ball park.

I have no idea how stopleak would work on this. I wouldn't recommend it.