Leaking Nozzle in Ultimaker 3D printers Posted January 12, 2017 All that said - perhaps my question to the forum is. When you replace the Olsson block - where do you buy them? And do you know what parameter to pay attention to? Hi, I see you are in the US. In which case you might want to look at / talk to fabrc8. They probably are the ones that made your printer anyway. The other source I know of in the US is gr5. They carry Ultimaker parts and also 3rd party mods. There might be other good sources, but those are the two I know and have purchased from. Plus they are both active members on this forum. Hope it helps.