Copy of email sent today to Pennzoil:
"Sirs:
I purchased a container of your engine flush at WalMart last night. At the checkout, a guy commented that he put the exact same stuff in his Ford Bronco, and it 'ate every seal on the engine', 'had oil coming out of everywhere', etc. Alarmed, I searched the internet for any information on your product, and came up empty-handed (Google, 'Pennzoil engine flush'). It would seem that this is a very risky product to use, and I'm going to return it tonight. I thought that you should know that there are many other products out there that are endorsed by the manufacturer as well as the public, and that you might consider beefing up support for this stuff if it really works as the container states. After all, if Pennzoil doesn't actively support this product, what does that say to me?"
- I searched this forum for information on the effect of flush-additives on seals, and found very little. It seems that it is possible, but why? Is the corrosiveness that eats gum and varnish the culprit, also eating seals? Or does this happen only if you leave it in the engine too long, or have bad seals in the first place? Or could the extra volume increase oil pressure enough to push oil out through the seal?

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1986 560SL
2002 Toyota Camry
1993 Lexus