If you have to ask that question you shouldn't do it yourself as removing a cylinder head is not for the inexperienced. if you do decide to do it yourself make sure you have all the proper tools, and a repair manual, you'll need a full range of metric tools including a torque wrench. follow the manual for the rest of the instructions.
Replacing the head gasket on any vehicle is a long and complicated process, however if you wish to see basic step-by-step instructions go to the related question on the right side of the page "How do you replace a head gasket?"
It can costs anywhere from 10 to 20 dollars to replace an oil pan gasket on a 20045 Nissan Sentra as of 2014. The exact price depends on the seller.
Yes
Replacing the head gasket on any vehicle is a long and complicated process, however if you wish to see basic step-by-step instructions go to the related question on the right side of the page "How do you replace a head gasket?"
More than likely you have a valve cover leak. You probably need to replace the gasket(s).
you will need to rebuild the whole motor. better off getting a used motor at a junkyard and replacing it like I did on my sentra.
Leak or blown gasket.
have a mechanic sheck for a blown head gasket or a craked head
either sell the car or pulley engine out
LOCATING THERMOSTAT ON A 1992 NISSAN SENTRA: FACING YOUR CAR THERE IS A HOSE ON THE TOP LEFT SIDE OF THE RADIATOR FOLLOW IT TO ENGINE. THE HOSE ATTACHED TO SMALL HOUSING ON ENGINE BY 2 BOLTS REMOVE AND YOU WILL FIND THE THERMOSTAT. MAKE SURE TO USE NEW GASKET AN GASKET SEALER. Per the repair manual. The thermostat is located from the bottom of the vehicle, off of the lower radiator hose housing. The thermostat "is not" located off of the upper radiator hose behind the housing connected with two bolts.
My 2001 Nissan Sentra GXE has a blown head gasket. My mechanic is quoting me $700 for labor plus parts (total in the $1200 range). Based on his hourly rate of $90 per hour, he must be planning on about 8 hours. Of course that's for an experienced professional. I'm sure if I were to do it myself (assuming I had the ability) it would take much longer.
you go to a Machanic.
replace head gasket