Oil Change Interval

[hbaker888]

I own a 2005 Chevrolet Silverado 2500 with a 6.0 liter engine, the truck is in excellent mechanical condition. I swithched over to synthetic oil at 93,900 miles in October of 2010, it is now August 2011 and since the oil change the truck has only been driven a few miles once a week and currently has 94,500 miles. What is the expected life of synthetic motor oil under these conditions.

 

H. Baker

[Superperv23]

You really shouldn't use oil for more than a year, every heat cycle it will break down a bit. Since you are doing like 70miles a month if it is ok for longer is anyone's guess, you are never going to find a test to tell you how long it will last under those conditions. Basically unless you have the oil analyzed yourself, which would be a waste of a fair chunk of money, to say it is ok you should likely swap it out when it has been a year to be on the safe side.

[Porter_]

You really shouldn't use oil for more than a year

 

i agree with this, i'd change it at least once per year. check the owners manual, it should give a maintenance schedule in the form of "change oil every XXXX miles or every X months".

[donjames911]

I knew a mechanic who serviced tanks in Korea. He said that due to oil shortages, he'd test the viscosity of the oil between thumb and index finger. If the oil maintained a 1/4 inch bridge (and obviously no metal fragments), he would only replace the filter. He said he treated his own vehicles the same way and never encountered problems.

 

Now I don't know if that's bullfark or not, but I do know that viscosity is the most important attribute of lubricants. Oils have improved to the point that we now have synthetics, but the change interval has changed from 12,000 miles down to 3000 miles and yearly replacement as a minimum. On my Jeep Grand Cherokee SRT7 and my GMC Sierra Z71, I stick to a 6000 mile schedule. But on my toy, a '97 Land Rover, with synthetic oil, I follow the mechanics advice. Time will tell.

[dewfpo]

I know what others will say but I have a few vehicles that I use infrequently and I have lest synthetic oil in them for 3-4 years at a time. I just make sure that when I do use them I get them good and hot for a long enough period to boil off any condensation. I have not had any problems for 20 years doing this.

 

DEWFPO