Lets say you have a vehicle with 170K on it that runs fine...it's a Nip built Lexus (Toyota)...that actually does run fine. Would there be anything wrong with switching to some Syn oil in it now?

 

dont see why not, its when you change to syn, then you're not supposed to change back to regular......... I THINK

 

hmm...id be "hesitant", but if u really want to...go with something a lil thicker.

 

The motor is in damned good shape considering the milage. Leaks no oil or uses much if any. I guess I'll give it a shot here by months end.

 

i read somewhere before that after you have a lot of miles, that even if you used dino or syn to stay with it. it was like from the engine oil bible i found on some website.

 

Changing to synthetic in an old high mileage engine can sometimes be a bad idea. Synthetic oils keep engines much cleaner, and will actually loosen the deposits inside an old engine, which can do two things...1)Cause it to rattle, because the deposits were helping keep things tight. 2)Eat away the deposits around the seals, and cause them to start leaking.
On the flip side, some people have reported that switching to synthetic made their engine stop leaking oil, which is due to the new oil softening the seals.

The only reason I tell you this, is because too many people dont have the common sense to realize that the reason these things happen, is because synthetic oils are much better than traditional oils, and then they turn around and accuse the synthetic oils of being trash, duh!

 

Hrmmm...

 

I had to run, and didnt get to finish...

If the engine was taken well care of, and the previous owners were **** with their oil changes, you should be ok, but it's something that you just dont know. I switched to Amsoil in my 130k mile beater truck (92 S-10), and it runs better than ever. I run Amsoil in everything, but was scared to switch over after I bought the truck. After going through 3-4 oil changes with regular name brand oils, and losing almost all oil pressure EVERY stinking time at 2500-3000 miles, and being forced to change again, I got sick of it and switched to Amsoil oil & filter. I'm at about 7k miles now, still have full oil pressure, and it seems to even run a little better. Yes I'm spoiled, I'm used to being able to go 20k miles or so per oil change with Amsoil:p

 

Well she's had this car since about 60K mi and I've done the oil changes since about 100K to now. I've always ran Val 5W30 in there.

It's a better built motor so I think I'm gonna give it a whirl here.