Maintenance on a 2005 Nissan Sentra 1.8S

Question

My previous car was totalled and while shopping for used cars, I have found a 2005 Nissan Sentra 1.8S on sale for a very good price. It is being sold by the current owner, and it has been going to the Nissan dealership pretty regularly for routine maintenance (oil, filter change, eetc), so I am happy with the current state of the car.

It has clocked ~50k miles and that, I guess puts it in the "major preventative maintenance" mode.

The owner had never "popped the hood" before, so, when I did, to check the engine out, I noticed the following:

1. The Engine coolant reservoir has an absurdly low level. It's like 5% of the reservoir volume.

   I am sure that, any vendor, including Nissan does a check of the coolant level during their routine maintenance, and the last check was 9 months ago, and given that the car had been driven around only 10k miles since, I am concerned about coolant leakage.

   I asked the owner to turn the engine on and the exhaust does not blow white or blue smoke, so I guess that rules out coolant leaking into the engine?

2. The engine made a screeching noise for the first 5 - 10 minutes after a cold start, like this: http://www.youtube.com/watch?v=abqYkjT2zf4.

   I could not see the belt drive closely enough but the "serpentine" belt drive design itself looks a bit weird: there's the belt coupled to a basic pulley system on both ends and the whole setup is under tension somehow and that worries me:

   i. I am unable to closely inspect the state of the current belt and can't confirm if the noise is due to the belt itslef or from the power steering belt!

   ii. If I end up buying this car, I would have to go through a lot of trouble loosening the tension and putting it back on just to inspect the state of the current belt, and I am not aware of any other system on the car that can make such a screeching noise (need help and suggestions here)

3. This model has large number of reports of a blown head gasket. http://www.carcomplaints.com/Nissan/Sentra/2005/engine/blown_head_gasket.shtml

   My assumption is that these reports are an insignificant portion of the total amount of models sold in the US (otherwise they would have been legally required to do a recall, wouldn't they?).

   If my assumption is false, then Nissan is an irresponsible company indeed, and I should not buy this car (or any of their models) to begin with, but given the large number of Nissan Altimas I see around, I would like to believe that those reports of a blown head gasket is within a small margin.

Keeping that in mind, short of an expensive ($200+) pressure test, how can I confirm or estimate if this particular car could be one of those with a blown head gasket in the future? (The absurd coolant level worries me)

Or, failing that, is there any "preventative maintenance" I could do to keep the gasket from leaking?

Answer 1

1. The fact that the CO didn't know about the low coolant level was low worries me. It could be leaking coolant when warm (when the pressure is high enough to squeeze through a pinhole, or whatever), or the engine is burning a small amount of coolant. This could be a head gasket or intake gasket(s).

   One thing to be sure of is that you are reading the correct level. Sorry if I'm patronizing you, but there should be two marks on the overflow/reservoir: One for the cold level and the other for the warmed up coolant level. Obviously, you check the former when the engine is cold, the latter when warm.

   If the engine bay is dirty, oil leaks, low/dirty brake fluid, etc. I would probably pass on it unless I felt like doing a lot of maintenance in the future. 50k miles is pennies for a 2005 Nissan, and it should be in better shape. If the owner didn't check the coolant, what else could have gone bad?

2. Drive squeaks are generally very minor problems that just indicate a loose and/or worn belt. You should be able to shine a flashlight down there and see if the belt looks excessively worn/dry. If it is, it will have dry cracks all through it and should be replaced. In the meantime you could up the tension to make the noise go away.

3. Given that the coolant has mysteriously disappeared, and this somewhat commonly occurring problem with head gaskets, I'd move on. This is a late answer, so if you bought it already it's not the end of the world, but there are other fish in the sea.