It is time for an oil change in my 1986 Daimler Double Six V12. I use Castrol Edge synthetic in my 06 Super V8 and am considering it for the DD6. This car is not a daily driver, has just 64K miles on the odometer, and has gone only 6,000 miles in the last 14 years. Is there a down side to synthetic in an 80s V12 other than the expense? Would synthetic last longer in a seldom-driven-very-far pampered V12? Any weight recommendations for 20F to 90F usual ambient temps?

 

Nope!

And, IMO, no particular upside, either...but that's a different question and different conversation



Hmmm. Good question. I'm not sure if synthetics "last longer" in low use situations. Oil life depends more on how a car is driven ....when it is driven. It doesn't wear out just sitting in the sump.

Others will chime in.

How often do you plan on changing the oil?

Most v12 owners like 20/50, as do I. But I find it a bit heavy in subfreezing situations so I switch to 10/40 for winter.

Cheers
DD

 

Most OEMs do not give extra time allowance for synthetics over dino. It's whatever miles or 1 year whichever comes first.

If the car is being stored over the winter, it's best to change the oil before storage rather than after to make sure any acids/ moisture are not sitting in the sump.

 

Thanks for the replies, guys,
Yesterday I checked out Castrol Edge at the local Wally-world and discovered they now carry a “European Formula” 0W-40 full synthetic. I bought 10 quarts there plus a Wix 51231 filter from O’Reilly’s.
Back home I checked the oil out on line and found reviews are almost universally positive. Most indicated that this oil is made in Germany and imported to the US in bulk for re-packaging, but the two 5 Qt containers I bought say made in Belgium which I found interesting because my car was first delivered to Belgium in 1986. Karma?
I remember early warnings about using synthetic oil in older high mileage engines when it first came out because it might leak past old seals, but I am thinking I will try it in my V12 and see what happens unless anyone has a good reason not to.
I am ashamed to say how long it has been in time since the last oil change because the car sat in the barn for quite a while awaiting its turn for re-commissioning while I worked on a home addition. I am thinking less than annual oil changes in the future to go along with still few but more frequently driven miles to keep things stirred up. I plan to flush and replace the coolant too before fall driving and winter setting in; sticking with Prestone green stuff rather than OAT. I already replaced all four calipers and used DOT 4 in the brake system (man those rear calipers are a B___h.)

 

I made the switch to Castrol 0W-40 full synthetic and a Wix 51231 filter today, and so far have seen no change in oil pressure. Cold (well, 80 degrees F) it was 4 Bar (58 PSI) at 1,100 RPM and when warmed up it was 2 Bar (29 PSI) at 750 RPM idle rising to 4 Bar at 2,000 RPM - same as the Castrol 20W-50 oil I replaced. 10 quarts US made the oil level in the middle of the hash area on the dip stick even with the filter change.

On the coolant issue, checking back in my notes I had filled it with Prestone Dex-Cool when I replaced both thermostats and later when I had a leak I forgot and added Prestone green with Prestone radiator sealer. No leaks now, but I emailed Prestone to ask if I had done any damage with the mixed coolant. There were some deposits in the long filler necks; gray in the expansion tank neck and brown in the block filler neck. It was down about 20 ounces so the necks were exposed.