Nissan Repair: Nissan Altima problem, nissan altima, radiator cap

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Von,

My son has a 1996 Nissan Altima with ~100K miles.  4 months ago, the some gaskets were leaking oil and replaced.  Just before this happened, the engine light went on.  My son informed me that the engine light is on again as well as as the overheating light.  Could it be the thermostat?  Is the location of it easy to get to on that model?  I'm trying to determine if I should fix it or need to go to a garage.    Thanks for your help.  Dave Valent
Answer -
Dave,

First check the antifreeze level.  Be sure there is sufficient coolant.  If there is then replace the thermostat with a Nissan thermostat.  Aftermarket thermostats are cheaply made compared to the one from Nissan.  Also, get a new radiator cap from Nissan.  Now, if the thermostat and the cap do not correct the problem and you are not leaking coolant I would be taking it in to a shop as it might be a headgasket.  Cooling issues are a graduated approach adn you start with the cheapest first.  I do not know if you are into taking the head off the engine to replace the headgasket.

Von,

Thanks for your propmt and helpful advise.  One other question.  My son lives about 150 miles from me so I don't have access to see the engine right now.  Is the thermostat easily accessible?  I assume it is, like on other cars, but I want to make sure before making the drive out to try to replace it and the cap.

Thanks.

Dave  
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Dave,

The thermostant is a breeze to change.  Be sure to get a radiator cap too.  The thermostat neck bolts are either an 8mm or a 10mm.  

Thanks Von,

I spoke to my son today and asked him to check under the hood.  He said that while the level looked a little low, he could see some anti-freeze in the radiator.  However, he noticed some fluid on the ground, so I suspect it is leaking from somewhere and probably from the head gasket based upon your inital reponse.  For background, what was done in March was replacement of the front crank seal, valve cover gasket and oil pressure sending unit.  In light of the leak, do you think it is still worth trying to change the thermostat?  This has been a good car for my son, but we seem to be putting more and more into repairs and it's always a question on when to 'cut your losses' on a 9 year old car.  If the garage takes off the head gasket, might as well change the timing belt....it goes on and on.  Your advice is greatly appreciated - Hope I am not becoming a pain.  Regards,  Dave  

Answer
Dave,

OK, since there is a leak have him fill the car up with water and find the leak.  First correct what is leaking and if they worked on the engine there is a good change that they left something loose or tryed to save you money by not replacing parts that looked OK when they worked on it.  So, find the source of the leak and then go from there.  Never assume the worst unless everything else has been exhausted.  It is cheaper that way.  If the engine has a leak it will run hot and never get up to pressure.  You should be running somewhere between 13 and 16 pounds on the system.  Water boils at a much higher temperature when it is under presure.  No pressure, like a leak, means that the thing is going to overheat really easy.  This is especially true of newer cars with all the emmission controls on them.  So fix the leak and then go from there.