2004 GX470 195k switch to synthetic?

[Hessam]

Hi, I picked up a really clean GX470, and I'm using it as daily driver to work 3-4 times a week. Average about 1500 miles a month, probably 75%+ highway. Have all service records from previous owner. He did 5k changes with conventional...mostly at the dealer, but there are a couple of Midas specials thrown in here and there. It runs and drives phenomenally for an 04. Engine is not leaking or burning any oil. Really wanting to extend my OCI to 8-10k and wondering if it's safe to switch to a quality HM synthetic like Mobil 1 Extended Performance High Mileage 5w30. Or even the new RGT synthetic, but not sure I could extend my OCI with RGT, and little worried my MPG will drop slightly. Any recommendations?

 

[Jackson_Slugger]

Should be no problem, the odds are that the "conventional" he was using was an unadvertised syn-blend anyways...

 

[Rygrego]

A change to synthetic will have no ill effects. The OCI is your call. You can use synthetic with confidence and don't believe the wives tales so many speak of about leaks when switching.

 

[spasm3]

Mostly highway? If its not short trip hwy, and i think its not at 1500 a month. Why not Mobil 1 Extended Performance changed at 6 months or so.

 

[Boss302fan]

I use Valvoline HM full synthetic 5W30 with Maxlife technology in my 2006 Lexus GS430 and it seems to run smooth as silk... Zero leaks.

 

[ejes]

Personally, with the information you have given, I would switch to SuperTech High Mileage full synthetic and stick with the 5K oil change intervals.

 

[ARB1977]

How does the top end look? Take the oil cap off and look. If there's neglect I wouldn't go the distance you want to go until it's cleaned up. Maybe change the pcv for safe measure.

 

[dblshock]

do your favorite flavor then run a used oil analysis at 5K like a normal person.