So i like to change my oil every 2000 miles. I call up the parts store to send over a few quarts of castrol and a delco oil filter. They screwed up and sent my castrol (synthetic). SO i say hey, wat ta hell, ill try it and see how it performs. I drive for about 500 miles, no noticeable change in performance.
I was pulling out of my driveway one morning and my dad calls me screaming saying that i was pouring oil on the driveway. I brought it to work and threw it up on the lift.. it turns out 2 tranny/engine seals were pissin and some other one i dont remember. i drained the synthetic, put a new filter on and continued. now, another 500 miles later, the leak has went down. not gone obviously but barely there. I plan on fixin them when i go away in 2 months but i sure as hell will not recommend synthetic to anyone that has not used synthetic from DAY 1. Castrol is still the best choice, but there syntec does not go into my motor again.

 

no ****, Your not suppose to use synthetic on Older engines with high mileage since the synthetic oil cleans the engine alot better then normal oil. If you go on any oil company site they tell you that you should try there flush liquid first. to see if you have leaks or not. Because how synthetic cleans your engine to run better

 

I'm running on Royal Purple (EXCELLENT but expensive stuff) in my 2001 and I don't have a single problem.

 

ive been running synthetic in my 01 sonoma...no problems here

 

back when I bought my 2000 blazer (4.3l) a year ago I decided to try mobil 1, Im now just on my 3rd oil change with it and running well.