Any reason not to run Castrol 5w50 in a vintage Pontiac 400 ? I have 7K miles on a rebuilt Pontiac 406 with a smaller hydraulic roller cam . The lifters have always been a bit noisy . Tighter lash helped but viscosity from 10w30 - 15w50 never made a difference. The engine runs excellent and not hot or fussy . Gets great mpg for the vintage . 10w30 was a bit light on oil pressure- 18 psi at idle . I’ve primarily ran 10w40 but like my psi with Mobil 15w50 especially when it’s really heat soaked in the summer . I still like the increased ZDDP even with the roller and I don’t like having to buy boutique oil online . So I came across Castrol 5w50 that a local Oreileys stock and have a killer deal on right now . I emailed Castrol - they say it’s about 1400 ppm zinc & 1228 phosphorus. It’s 103cst @ 40c / 16.7@ 100c . That just looks like a real thick 40wt to me and it’s thinner than penn grade 10w40 at 40c ! My bearings checked out .0025-.003 on the mains .003 rods and .0025-.003 on the lifter bores . I mainly just cruise , I don’t beat it but with 3.90 gears , she’s a little wound up on the interstate. Thank you .
Castrol Edge 5w50
- Thread starter Quadrajet
- Start date
I used it in the MGA in my signature for a number of years and it always performed well for me. To provide some background the age of the motor is unknown, it has been in the family for 30+ years and never opened other than valve adjustments. I run the motor hard once warmed up, and similar to you when I get it on interstate I can get it well into the upper RPM band for extended stretches due to gearing.
I moved away from it to Mobil 1 15w50 only due to convenience, the Mobil 1 is easily available at Wally while the Castrol EDGE I could only find at AAP which was a special trip. I'd run the Castrol EDGE 5w50 again without hesitation though.
I moved away from it to Mobil 1 15w50 only due to convenience, the Mobil 1 is easily available at Wally while the Castrol EDGE I could only find at AAP which was a special trip. I'd run the Castrol EDGE 5w50 again without hesitation though.
I love Pontiacs. That oil is fine; I would probably run a nice 10w30. But your Pontiac mill won't know the difference. Good choice on the roller...
I used it in a Land Rover that featured the old Rover KV6 engine. The two oils recommended by LR were Mobil 1 0w-40 and Castrol 5w-50. I ran the Castrol 5w-50 with a Coopers oil filter. That vehicle had lots of problems but lubrication wasn't one of them.
Thanks ,there isn’t much info that I can find on this oil - especially the new SP formula . I’m gonna stock up on some and use it then . I like the idea of the 5wt over the 15w50 just for the colder starts is what interested me . O’reileys has $34.95 for 5ts any castrol + $15 gift card until 11/25/25 for anyone interested.
I tried the Castrol 5W-50 in my 1990 Porsche 911 for a while...but went back to the Mobil 1 15W-50, the engine in the Porsche just seemed quieter and smoother with the 15W-50. I don't put a lot of miles on that car and change oil once a year so I don't really have any comments about endurance, protection, etc.
Out of curiosity, what kinda of bearing clearances does a 90 911 run ? I notice a lot of high performance Euro rides spec 40 & 50 wt oils . Surely they are not running looser clearances then an old Pontiac V8 lol Some guys say a 50wt is just to heavy for my engine . I think modern synthetic 5 & 15w50 oils are a whole different animal then the old 20w50 Kendall’s & GTX brews we ran in the 80s . I don’t beat on this car but it does tach about 3400rpm at 70mph . I’d like to do a once a year or 5k miles oil change and call it good .