hey, whats up? I have 90,500 miles on my 05 X. Can I still switch to synthetic or a synthetic blend? and if so any good brands? will I notice a difference in the way the engine runs? (smoothness, etc)

 

i've changed it up in the past and never noticed a thing different. Why the sudden consideration of syn oils

 

Search the billions of oil threads but short answer -- it's never too late. Go Amsoil, German Castrol (search that if you're not sure what it is) or Mobil1.

 

i hitted about 70k going on 80k, still uses royal purple for about 3 years or 4 years.
never loss power...

 

I just bought my G with almost 100K miles on it and I put Mobil1 and it runs perfectly fine. I will though use Amsoil for my next oil change. It is what I have in my tranny, diff and clutch.

 

The dealer uses synthetic blend. i'm thinking of switching to full synthetic really soon. I only have 32k miles.

 

If you have no existing oil leaks, you should be fine.... one oil leak anywhere could become a slow gusher in time. This is the main issue. Also, synthetics tend to run high detergents, so if your engine was dirty, it may loosen some deposits and lacquers. Some of it will burn off, much of it will be sent to the oil filter (use an excellent filter). My suggestion is to use high mileage synthetic (Mobil 1 or whichever) which carries more detergent additives. Run the oil through and change it at 1K miles, do the same thing again for the next oil change of synthetic. This should clean your engine out safely or expose any leaks (the bad news).

Good luck

 

I say switch to M1 fully Syn. and change it every 3.5K miles using a NISSAN filter.
I've seen my G sedan engine (34k miles) with the front cover off and the oil pan off and it was SUPER CLEAN!!!!
Have pics somewhere...
Even the Tech's were very impressed.

 

I have 130k + on a 05x using Amosil 5w30 or 0w30 and a K&N Wrench off oil filter. Still running strong Wasnt too impressed with M1

 

I think that's a myth and dates back to old gasket technology.

 

^True story.

BTW, I've heard good things about NAPA Gold filters. Its what I use myself along with Mobil 1. I'm happy.

 

I could be wrong, but I thought that the high detergents in synthetics may remove/dissolve sludge and gunk that hardened at the point where a leak existed (sort of like removing scar tissue or coagulated blood). The oil, in this case, does not cause the leak, it simply exposes it further.

 

NAPA Gold filters are made by Wix so yeah, they're good.

 

If you go syn now, go with something on the thick side to be safe like at least a 10-40 or 15-50.