chevy 4.3L V6 - Pennzoil, Castrol Startup or M1?

Cape Cod, MA
FWIW, my company-issue work van, a 2001 Safari AWD with the same engine, gets serviced at Jiffy Lube (company requires it [Roll Eyes] ) with Pennzoil 5W-30 dino and a FRAM-clone filter every uses less than a quart between changes and doesn't seem to be developing any bad habits. I did convince the Jiffy Lube people to use the larger 3980 filter, though...

Brett Miller

Thread starter
No, mine had a so-so UOA with Mobil 1 10w-30. So I thought I would give GC a try when it was on sale at Autozone. I think the guy that had great UOA's with Pennzoil was also using Lube Control in his oil.


Staff member
New Jersey
Hi, 98 S-10 ZR2, 4.3L V6. driven only on weekends (sits at least 5 days between use), but the oil is always up to full temp when it is used, as 90% of use is on the highway. Im doing an auto-rx treatment, as I had the intake manifld gasket replaced, due to some elevated K and Na readings. Engine longevity, performance, mileage and cleanliness are the main factors Im interested in. I dont care about changing the oil, and the $$$ isnt important, as its relatively cheap one way or another, and I want to keep this truck for a LONG time. Need to decide new oil to use. There are LOTS of excellent pennzoil UOAs from this engine (cruising RMP 2000 at 70 mph, so shearing isnt an issue). Ive also seen the castrol gtx startup oil, which may be a good setup, as its probably GC ester in GTX dino oil. I dont think GTX is as good as pennzoil, but this looks liek a promising oil, I have heard that the wear rates at startup comparing this oil to say M1 are pretty impressive. Or good old M1. Reviewing the UOA archives, I havent seen that much good from M1 and the 4,3L engines. I have had excellent results with it in my father's toyota previa and mothers plymouth breeze. pennzoil, changed twice a year looks really tempting, but Im worried that shell is going to ruin pennzoil motor oil like they have the pennzoil long life oil. Any ideas about that? Any comments or suggestions would be great. these three are my oils of choice, and Im not very interested in using others. Many thanks, JMH [ July 12, 2004, 01:09 PM: Message edited by: JHZR2 ]