Nissan Repair: Nissan Altima - rattling sound, pushrod engine, nissan altima

Question
I have a Nissan Altima 99. It had been sitting idle for a month in cold Nebraska weather. It was ok for a week and then started giving some rattling noise and the 'change oil' sign was on. (temp outside was -12). So, I got the oil change and the noise slowly went away. Car was fine. Now again (after a couple of weeks again when temp outside is -12) the 'change oil' sign is on and the engine is making much noisier rattling sounds. like a bulldozer. What can be wrong? Is it the weather...

Is there any hope?

Thanks.

Answer
Change the oil again and go with Mobil 1 5W30 as it is really cold where you are and the oil is probably coaked up.  If nothing else Mobil 1 5W30 will flow when other motor oils won't.  Give it a try and get back with me.  The noise you are getting is probably the cam followers.  These are like the old lifters on a pushrod engine and they clock when they do not get oil pressure to them.