Edited on 2008-02-25 21:25:48

A rebuilt 1987 Jaguar XJ6 engine - used Valvoline VR-1 20-50 "Not Street Legal" for break-in oil. Now using VR-1 20-50. Any thoughts on the best motor oil for this motor? I've been told to not use synthetics.

Submitted by zurdo_1@univis… on Tue, 02/26/2008 - 09:02

I've been told by three different Jaguar techs, in three different States, to not use synthetic oils in the 4.2 or 3.8 engines so I never do. (for the same reason, it seeps through gaskets more easily, creating leaks). Besides, synthetic oil is more expensive, so why throw money away?

I have not seen the Castrol High Mileage 20W50 at Walmart. I never believe the odometer (mileage) reading in these cars. Speedos can be easily replaced. If it says "28k" I always think "128k". If the car has been restored, the mileage reading is definitely not real. (why would you need to restore a 28k mile car?). Unless the owner can prove the mileage, and that is another story.

Submitted by ekimp252@aol.com on Tue, 02/26/2008 - 08:47

What aboul the Castrol GTX 20W50" High Mileage"?Anyone have any info on it?That is what I am using in my 85XJ6,40K on the clock,but I'm thinking higher due to other issues.Thanks.

Mike Pressley
85XJ6
00XJ8

Submitted by smose2400@sbcg… on Mon, 02/25/2008 - 21:06

UPDATE

After more research it seems clear that the zinc levels in Castrol 20-50 GTX have been reduced over the years. Castrol has introduced a new oil, if you can find it, called CASTROL SYNTEC 20-50 for "Classic Cars" (100% synthetic) which has an additive package bringing the zinc level to at least 1,400, accoring to the Catrol rep to whom I spoke today. They will not comment on the zinc level in GTX 20-50 saying that is "confidential." For now...I am staying with conventional oil Valvoline VR-1 Racing Oil which has an additive package for zinc and phosphorous with the zinc level at 1,300. My concern with synthetic oil is possible leaks.

Scott

Submitted by zurdo_1@univis… on Fri, 02/22/2008 - 23:11

Edited on 2008-02-22 23:12:39

if you ask the Jaguar mechanics I know, who rebuild 3.8 and 4.2 Jaguar engines, they'll tell you Castrol 20W50. so that's all I use.

But before you go anywhere, go to the GENERAL DISCUSSION (First forum in the list), and read the article on oil, "Oil in Old Cars".