I've heard that changing oil types(i.e. convetional to synthetic) after a long time can be harmful. Is there truth in this or will I be fine goin to synthetic oil my truck currently has 110,000 miles and as far as I know(bought it used) it has always used conventional oil.

 

The only trouble you MAY have is the syn. oil cleaning any gunk clogging any bad seals causing them to leak. I wouldnt worry about it. I went to synthetic on a truck with over 150kmi and no leaks.

 

I changed to synthetic in and about 100K miles I use Moble 1 15w50. i have had know problems what so ever. There are a dozen reasons why synthetic is better over conventional the only down fall is it's expensive.

 

awesome thanks for the quick replies guys.

 

mojo is there any reason ur running such a heavy weight?

 

It is true. if the engine has sludge it will break it all up. Check the inside of your oil cap. Does it have brown/black sludge on it? I got my truck with 155k on it and started running royal purple. Front crank seal went out and that is about it.

 

The difference between mineral based oil and synthetic oil is strictly the base oil (unless you switch from regular to high milage or regular to extended drain, etc.).As you may know, Syntheticis man made to have better cold temperature flow and better/higher high temperature burn off. The add packs (dispersants, detergents, viscosity modifiers, etc.) are the same (ie Mobil 10W-30 mineral versus Mobil 10w-30 Synthetic). People see problems with syntheic oils in older/high milage vehicles if seals are worn, cracked, etc. This is due to the synthetic's excellent low temperature flow properties. Most people won't experience this issue so switching to a synthetic after 10's of 1,000's of miles shouldn't be a problem. if you are concerned, start with a semi synthetic to see if you experience leaking or excessive burn off. If no problems arise, move to full synthetic. I'm not a Tribologist, but I worked with one when I sold CAM2... this is what he told me.

For what it is worth, at 95k I switch to Mobil 15W-50 full syntheic from Valvoline High Milage... not a single problem to date.

 

A few years ago Consumer Reports did a test on engine oil and frequency of oil changes. They did the test in 50-some-odd New York City taxi cabs. All new engines, rotated the shifts and area they covered, to try to get even wear, etc. Their conclusion? No oil was better than the next (synthetics included), and there was no advantage to changing your oil earlier than 5000 miles. They recommended buying the cheapest oil you canfind and not to change it before 5000 miles.

 

i agree why are a cupple of you running 15w 50?

im sorry maby its just me but i have a hard time beliving there results, id like to see the report myself