I have a 2002 Chevy silverado 1500 Z71 4WD 5.3L V8 and as far as ive know from when i bought the truck in excellent condition used at 110,000 miles its oil isnt synthetic. So what im wondering is, is it a very bad idea to switch to fully synthetic from non synthetic motor oil? ( i hear people say switching to fully synthetic from non synthetic will shrink your gaskets and will also cause leaks) and if switching to fully synthetic from non synthetic is a bad idea, whats the best oil to use for my truck which now has 121,000 miles on it?

 

I've never heard of any negative effects by going from non- to fully-synthetic. I've only heard to never go BACK to non- after already being full-synthetic.

 

Actually going from non to fully synthetic is very beneficial, you should notice a difference. i know that i do. i change every 3k miles and my engine runs like its brand new, of course i only have 83k miles but my engine is clean as can be and runs very smooth

 

i switched on my 01 from non synthetic to fully synthetic and it only improved the way it runs...im at 194k and it still gets synthetic and is leak free

 

Switched to full synthetic when I bought my '04 Silverado used with 74,000 miles -- no problems with it whatsoever.