Castrol GTX High Mileage 10w-30

Not open for further replies.
Oct 22, 2017
Dayton, TN
Just curious. What is everyone's opinion on Castrol GTX High Mileage? I'm going to run it in my 1994 Ranger 4.0 and looking to see what kind of experience people have had with it. Will it really condition seals and prevent/stop oil leaks? If not, is there a HM oil that will do this? Thanks!
Last edited:
HM oil has a special 'lotion' for rubber seals to keep them from drying out. When they dry out, they shrink. When they shrink, you get leaks.
I ran it in my Liberty for 2 OCIs I think (maybe a third, don't remember). It's an oil leaker. I've also ran Maxlife in it. With the Castrol, the oil level wouldn't move for about 1000 miles into the OCI, then it would leak again. Maxlife I'm not even sure it's doing anything, so Castrol in my experience wins against Maxlife. In my 96 Cherokee, I ran Maxlife in it when I got it and still got oil drips after a few changes. Started running Pennzoil HM in it and the drips stopped, at least enough to not hit the ground. I probably have to add about a quart every 2-3k for it, which I'm happy with. One that I don't know about is Quaker State Defy. I'm guessing as a SOPUS oil it's like Pennzoil HM but I don't know.
It's good oil. I have run a lot of it and am still running it ( 3 years exclusively now ) in my son's 04 Concorde. It is still on the "thick for grade" like I prefer. Pennzoil HM is also very good and is also thick for grade.
Not open for further replies.