So, considering switching to t-6. I live in Boston and currently run Castrol 20-50. The t-6 I'm looking at is 10-40 and will run it for winter use only. Synthetic. When making the switch, I will also change out my current t-stat to a 180f t-stat genuine rover part, thanks to Rover's North. Orange goo for antifreeze with water wetter (royal ice).

How many "yea" vs. "nay" votes for the oil?

 

I thought T6 full syn was 5W40, which will help starting in the grip of winter. Orange goo Dexcool I'm not a fan of.

 

Rotella T6 is 5w40, T5 is 10w40.

The Dexcool is a mistake.

 

yea t6

 

my bad...t-6 is 5-40

 

Any 20w-50 or 40 weight oil is good. I stick with Mobil 1 Delvac 15w-40 all year.

 

I use Rotella T6 all year, thats summer and winter, 5,000 oil changes.

 

Spike makes the most important point, not extending drain interval because oil is "better" or "more costly".

A certain quantity of metal circulates in the oil, so fine that it passes the filter, and is only reduced by drain and refill. If you leave it in twice as long, you are working against yourself. The Buick engine was not designed to be clean burning ultra low polluting and such. It was put to pencil in the late 50's.

 

Hey SB, I used the orange stuff in 2009 when I did the "Disco Mike 60K mile system makeover." That is what was recommended at the time.

Given the fact that I plan to swap out my thermostat this fall with a 180 D model and redo my carb/thermo plate thingy I thought it a good time to flush and renew the coolant. What is the going thoughts on coolant types now for a 2003? Sorry if this is hijacking the OPs thread.

 

Well, you skipped your bed time reading of "Brit Lit" (the RAVE and owner's manual). Where it advises to renew coolant every two years or 30,000 - which ever is first. So you should have changed one time again, and becoming up on the second time in the next month or two.

From page 187 of owner manual :

the anti-freeze content should be checked once a year and completely
renewed every 30,000 miles (48,000 km) or 24 months, whichever is the sooner. Failure to do so may cause corrosion of the radiator and engine components.


I like 50/50 premix green coolant.