general problems of the 2000 Chevrolet Venture

In January 2022, I noticed white smoke coming from the engine and a mechanic said it was the water pump that needed to be replaced, so I have it replaced. Recently, I noticed the same white smoke coming from the engine and took it back to the same mechanic who installed the water pump. The mechanic said it was the intake manifold that caused the white smoke. I decided to take it to another mechanic to see if the first diagnosis was correct and that mechanic confirmed the first mechanic's diagnosis and my previous experience with another gm vehicle (1997 vhevy lumina) that had the exact same problem: water pump went out and intake manifold also started to fail until the lumina's engine was fried.

Car is losing coolant quickly, even though I have replaced the water pump about a month ago. Due to gm manufactuing, they only allow dex cool coolant for their vehicles but not everyone carries dex cool. Also, the oxygen sensor code need to be read oxygen sensor only and not with 4 or 5 other codes.

Please investigate incidents of failure of the gm passkey/passlock/vats security system. Security light would flash and vehicle experienced a total loss of power. Problem occurred intermittently for the next several months, at various speeds. No accidents involved, but several near misses. Problem occurred very frequently in the past week, and now vehicle will not start due to security feature. I am using factory original keys, not replacements. Problem affects this particular make and model, but it is so systemic to gm, an entire aftermarket industry has arisen to bypass this security "feature. ".