Nissan Repair: 97 Nissan Altima - Smell from the hood + some common ques, valve cover gasket, nissan altima

Question
Hi,

I Have some questions regarding my Nissan altima - 1997 - 78Kmiles

1)
I did my oil change and radiator flush last month - I found some vapours coming from outside radiator after driving back from the autocare. I took my car back to them - the said its due to some water logged outside - they cleaned and no issues afterwards.

I am getting some kind of smell(oil +Metalic) - if I stand near or pass by the bonnet probably after a 20-30 minutes ride . This I am getting right from the begining when I purchased the vehicle at 75K miles - nothing to do with the oil change I guess. The temperature gauge never went beyond half way mark. checked coolant level, engine oil levels, brake oil, power steering oils. all are good,I havent checked transmission fluid level yet. I am worried whether I am loosing some oils and drying out somewhere,  what might be the cause?

2)The autocare person told that my brakes got worn out and we need to replace the front brake Rotors, pads and shoes - (around $500 approx) - whether this might be the cause for the smell - Do we need to change the Rotor for the front brakes - is itmandatory (its 78K miles now)

2)
If I turn the Key's on without starting the engine - I can hear some kind of sound like some air filling in from underneath probably from the backside also after turning off after a ride - I can hear some kind of sound going on for some minutes - like something still rotating from backside(like disc brake in bikes). I dont know whether its actually the correct functionality.

Thanks for your answers in advance.

Answer
Vinoth,

I would have the engine steam cleaned to get rid of any crusted oil or other dried fluids.  Then, I would monitor the situation to check for really slow leaks.  Now, what I am talking about is just where it starts to creap out.  You probably have a leaky valve cover gasket and the little that is getting out burns off on the exhaust manifold.  No worries, but annoying with the smell.  Brakes would not make the smell unless you were really braking hard.  If the car has 78K on it the brakes probably need to be replaced, along with the rotors.  You could check around for a better price.  rockauto.com is a good source for rotors and courtesyparts.com is a good source for the pads.  I would only use original Nissan pads to keep brake dust down and to eliminate brake squeak.  On the third item it sounds like you are talking about the fuel pump.  If it i9s staying on for some time after turning the engine off I would replace the fuel pump relay as it appears to be sticking.