so i recently did a switch to mobil one. i got my max in feb wt 28k miles, its an 03. auto.

in any case 2 weeks ago i switched to mobil 1...since then ive noticed a very weird na dextreeemely unsettling noise when the engine is cold. i usually drive it up to 3k-3.5k rpms when cold, but after the swith, as i approach 2.5k it starts to make such an unsettling noise i immidiately let go of the gas peddal.

the car had never run on syntheic...not to my knowlege anyway...

im thinking it was a bad idea to switch so late in the car's life and should goback to regular oil...

anyone ever hav thir problem? what is it???

it sounds as it the internal parts were rubbin on each other w/o oil!!

its scary...

 

Not sure I understand exactly what you are saying, but it might be the infamous "cold start rattle" experienced by many 2K2/2k3s. When you first start it and the engine revs up once it catches, it will make a very loud, irritating, and somewhat scary "metal on metal grinding" sound for about one second at around 1,700 - 2,000 RPMs. Apparently this problem is not as serious as it sounds.

 

no. it happens AFTER i start moving. after i leave my driveway im very short on cash right but im thinkin of switchin either bak to the reglar nissan oil, or try pennzoil synt.

 

28k is not late in the car's life to change to synthetic.

I am not sure what your problem is.

However, it wouldn't hurt to warm the car up for say 60 seconds and drive off slowly.

I don't drive my car at 3,000 to 3,500 rpms when it is cold and don't recommend that vehicle abuse to anyone.

Have you ever heard of Valvoline Synthetic Oil Treatment. I haven't seen it locally in British Columbia, but I am sure it is readily available in the US. Perhaps this product will help.

Apparently, it helps keep the engine clean, the oil slicker and improves fuel economy.

I heard about it on BITOG (www.bobistheoilguy.com).

If you can't get sound advice on the .org, perhaps try BITOG.

 

Good advice, above.

Actually, 28 K miles is low mileage for an 03. The average is about 10 K miles a year, which would make the average for an 03 at about 40 K miles. I have 64 K miles on my 04 (bought in May of 03).

This time of year, it is not that cold in the morning. How cold could your engine be? Given your low mileage, you still have a powertrain warranty (6 years or 60 K miles). Take it to a dealer you trust to see if they can identify the problem.