The usual stuff went on my Venture at the lower end of the mileage scale. The water pump went around 100 000 km and the plugs were finished at about the same time.
The biggest flop was the motor overheating and was finished at 135 000 km. After this I found out that the Venture and all GM models similar have the same problem.
The engine gaskets fail regularily and all of the coolant leaks into the internal parts of the motor. I have warned all the people that I have known and each and everyone of them has had to replace these gaskets.
An inquiry at the local Gm dealer advised that they are doing 1 vehicle a day with the same problem. More like an epidemic. I have known the same engines to verheat and blow with as little as 60 000 km.
Plain and simple I have found that North American cars are junk. I have put an engine or transmission in every car I have owned.
No I am not hard on cars, quite the contrary. I put a lot of time and effort into the service and have been stung every time.
That is why my last two purchases have been a Toyota and a Nissan. Both extremely reliable to date.
I also own a Venture. I have not had many problems with it. The main problem was with the fuel injectors. I am told by a local repair shop that GM uses injector nozzles with the smallest orifices. My van began acting like it had bad valves at about 60,000 miles. I found that it was the injectors. After a professional cleaning by this shop, the engine has run fine ever since.
As for the leaking coolant, this mechanic also stated that due to the different metals used for the block and intake, the expansion rates are different (by.003"/inch) which causes premature gasket failure in some cases. He also said that it rarely leaks into the engine cylinders. Since you stated that you bought the van with about 60,000 km (38,000 miles), that would lead me to believe that this vehicle was a lease, fleet, or rental van. Someone who owns such a vehicle originally also knows that they will be turning it back in, so small leaks, noises, and otherwise annoying problems may be left unserviced. This may be why your particular van experienced a large number of problems. In fact, the GM 3400 engine is considered to be quite reliable by many mechanics.