I run mobil1 extended performance 5-30 in our taco.



I run amsoil 5-30 in my 3.0 pickup.... made the synthetic switch when i got it at 194k miles.



No issues whatsoever.... just runs a little smoother.

 

I dont know about the US but here in Canada you can get a vehicle history report which gives you the names of the prievious owners

 

I got my 4runer history service history unknown it was a bussines leased vehicle for a few years.
I got it at 196k, drove it a few days. Ran a flush thru it with a new filter, changed the oil to synthetic 5-30 new filter. I am at 215k now with one oil change and 1 UOA on this so far. No leakes, tests came back ok ,but i wil use it as a base test for my next next one at 230k.
God luck have fun

 

I switched my 1989 toyota truck 22RE 4cyl 4wd to full syn at 78K miles, drove her to a dealership with 196K and traded her for my 1998 taco 2.7L 4cyl. 4WD and have run her on full syn since day 1, she has 285K right now runs as good as new. I've switched multiple vehicles to Mobil1 when i bought them used. Hubby has a 03 Saturn ion3 switched at 45K when we got it, no issues and that has 170K now. Bought an 03 Lexus RX300 and switched that to full syn at 57K, no issues with 80k now. The lexus had lots of build up at the top of the engine under the oil fill cap and that was evidence to me of dino/nasty cheap oil being used, its getting cleaner slowly.

I'd do it and would/will do it to all vehicles I own.
tina

 

i went to a synth blend ~80K, then to full syth ~90K on my 3.4
NO leaks after an additional 100K

 

Either or....I've ran Mobile 1 in mine since day 1.

 

That's my intention for now. Thanks to all for your input and suggestions. I may switch to synthetic down the road one day, but I arrived at a better understanding why one may see leaks after making the switch from conventional to synthetic at high mileage. For now, I'll just stick to what's always worked well for me.

 

If you really want to give it a fresh start, checkout www.auto-rx.com.
Its kinda expensive but from what i hear it works.