Usually get the strong smell when acetic cure silicone is used. Most people have gone away from that product and use a neutral cure which is relatively odour free. Unfortunately the only way to get rid of the odour is to ventilate the van. It will eventually disappear but it does take awhile until all the acetic acid evaporates out of the silicone.

No not true. I spent a lot of time testing various silicones and polyurethanes in my secular work. Some of the really high grade silicones used for things like curtainwall glazing are all neutral cure. For example Dow Corning 795 is a high modulus structural silicone often used for that purpose. That comes as a cartridge type single pack silicone. But if you have the right equipment you can get very high grade structural two pack silicone also neutral cure but the equipment to apply it is $100,000 + and the silicone comes in 44 gallon drums. The neutral cure is because acetic acid often reacts with various substrates to their detriment and also the interlayer in laminated glass. In high rise curtainwalling, the modules are completed in a factory in a controlled environment and every 10th panel is tested to destruction. That ensures the silicone has adhered correctly. When selecting silicones, read the label. If you are using it as an adhesive as well as a sealant then choose one that states high modulus regardless whether it be acetic or neutral cure. You need to know if the substrate you are using it on is impervious to acetic acid or not if using acetic cure. If unsure choose a neutral cure. I very rarely ever use acetic cure these days.