Originally Posted By: gregk24
Originally Posted By: ThirdeYe
Pennzoil High Mileage seems to work great in my Firebird. It had a slow leak that Mobil 1 High Mileage failed to make a dent in, even after 3,000 miles. After ~1,000 miles of Pennzoil High Mileage, it seems to be slowing down at last. In terms of performance, sound, etc. I can't notice a difference. I haven't tried their Super High Mileage, however, as I can't seem to find it here at any place aside from Walmart for a reasonable price.
It takes time to stop leaks with High Mileage oils, the M1 probably was working on it already and the High Mileage additives in the Pennzoil finished it up.
I'm not entirely convinced by that as in other leaking applications, when using MaxLife, the leaks have always slowed down (or completely stopped) in less than 3,000 miles. But, anything is possible. Perhaps it was working, but from the time I got the car until the time I changed it out, the amount of oil leaking was the same. I think that Mobil 1 High Mileage might just take longer to slow leaks than other High Mileage brands.