Re-checked the purge line and identified that there are in fact bubbles coming from the purge line.
Make sure the test fluid in the kit is fresh and not passed any expiration date. I did not see a expiration date on the fluid and was told previously that it can be reused over and over as long as it was not contaminated by antifreeze or any other foreign substance. i always dump the results anyways.
Make sure the test fluid has not been contaminated by someone else. Just me using it.
Make sure nobody has recently flushed the coolant system or changed the coolant. The coolant systems is constantly being added to due to it bubbling out while testing.
Make sure any recent additions to the coolant to adjust the level have been very small. They are cups of water at a time, sometimes more. Usually after it cools down.
Make sure the cap on the reservoir is tight and not leaking. I have tried multiple caps, and they all hold pressure until it hits that 243 mark or when the car says idle engine.
Make sure the pressure rating of the cap is correct and not failed. multiple caps tried.
Make sure the seal from the sampler to the tank is not leaking air, you want it to sample what's in the bubbles you are seeing. (No peeking) Using these samplers they have an angled plug that fits snuggly into the radiator cap outlet. you make sure that the coolant level is lower to allow for the tester to seat deep enough to not pull up coolant into the test fluid. I then connect to vacuum line and it starts to pull those bubbles up through the fluid. I have used this test on several cars and it works well. However after 2 different tests on this Northstar engine it stumps me.
Finally make sure the vapors above the coolant in the reservoir are representative of what is normal operation, in other words, that no fresh air has gotten in after an overheat episode. i can control the fresh air for this test at the radiator cap, however i am unable to tell if it is being introduced somewhere else in the system.
I appreciated your ideas and troubleshooting. Thanks