I know this was covered but the posts I checked didn't have the information I was looking for. I believe both Amsoil/Blackstone sell sample pumps. Which is best? I understand that the Blackstone bottle collapses with the Amsoil pump??
I think most of the bottles will collapse if you pump too hard and generate too much vacuum. I also find that the bottles are more susceptible to collapse when hot. I always pull up at least two bottles full and pour them out before I pull out the "keeper," that I send to the lab. This minimizes the chance of dirt in the tube or scraped from the dipstick tube walls, contaminating the sample. By the last pull, the bottle has become a bit soft, and even more likely to collapse a little, if over-pumped. Just pump slowly, and any should work just fine. Mine is a Blackstone, BTW.