Good choice: many extol the virtues of synthetics and boast of the number miles you can get, however, they rarely talk about how ANY oil is going to get dirty and should be changed accordingly regardless of whether they haven't deteriorated in their oiling capacity.JMHO

 

I used to run Valvoline MaxLife 10W-30 in my 115K mile 95 Z. Worked well.

 

I always ran Castrol Syntec 10W30 up until about 110,000 on the clock. Then I changed to Valvoline Max Life Full Synthetic 10W30, and the car has never run better. No leaks or blowby. Car still screams with no problems.

 

I use the Valvoline max-life in mine and it has about 100,000 miles on it. Used it in my 88 as well and loved it.

 

can you safely switch to max life synthetic without worrying about leaks? i read some other oil posts and someone said it has more swelling agents in it than other synthetics to prevent the leaks usually caused by switching at high miles...

 

Use GTX Startup 10w-40, thats what I use, and like the commericals claim it actually does protect on startup. How do I know this? I had a mustang w/ some bad main bearings and everytime I would start it up I could here them rattle a little and then go away after like 2 seconds, I put GTX startup 10w-40 in it and everytime I started it up it never rattled again.(temporary fix) IT has polarized molecules in the oil which stick to the metal. Trust me its good stuff. My car has 101k

 

I have been using Mobil 1 5W-30 full Synthetic since day one. I have over 135k miles on my car now. Around 93k miles I had some oil leaks, but I had them re-sealed for a minimal cost. No leaks since then. Maybe I'll start to have issues again in another 60k miles or so. But with an extended life oil filter and Mobil 1 I can go 6k miles between changes. Engine feels just as powerful now as it did 8-9 years ago, maybe even better??

 

i ended up getting castrol GTX 10w-40. i figure hey, it's gotta be better than the advanced auto parts stuff right? they were out of 10-w40 valvoline max life. i dont want to bother with synthetics(until i get a rebuild/new engine). and i didnt want to risk going to 10w-30. ill let you guys know how it acts once it is changed. and reading this made me remember i forgot to get a filter ah well, maybe ill get it on my break from work.

 

My 93 Z28 has 242k on it with only a few bolt ons and still runs low 8s in the 1/8. I have another block waiting in the wings but I dont think she is ever going to die though.

 

what does it say on the YC? kust rub 5w-30 below 45, and 10w-30 above it. don't worry, you'll go out young

 

Owners manual states 10w-30 is approved down to 0F.

Really I wish people would just start going to the oil board for oil info as most of what happens here is more ignorance gets spread because too few of us actually have any knowledge and those who do lack the patience and persistance to really get through to enough people.