OK here is where i am at . last i told you the mechanic said he checked the bolt and it was fine (I hope he checked it) He said he did a compression test and it was fine (again was not there so taking him for his word) he said it was absolutaly the thermostat being aftermarket so it told him about a compression leak tester that changes the blue liquid to yellow if there are gasses in the radiator to make it overheat (kind of on the same basis as the emmisions in the overflow for the antifreeze which my car failed detecting the co2) he said he would get one and test my car befor he did the thermostat.

so he got one and tested it and told me it was fine and the thermostate was the problem so i got one from st charles since for 2 weeks my mechanic said it would be there tommorrow, +1 for st charles got mine in 3 days. well after him putting it in he told me he took my car on a test drive and it was fine, good to go. great i thought untill i took if for my test drive an guess what , you got it . it OVERHEATED AGAIN!!

I went to autozone and got my own engine compression leak tester and sure enough it passed on this one. here is a pick and video of the blocktester and how it was used.



here is the video of the test and results

http://www.youtube.com/watch?v=X05PDw5IE1U


Here is the thing, I told the mechanic to get my car to over heat you have to drive it hard, meaning reve it above 3000 rpms. maby floor it a few times all when driving on the highway. for example I live in staten island , i took my car on the expressway for roughly 15-20 miles not to much traffic , I drive it around 50-70 mph moving the revs around from 2000-5000 . doing this the temp got right to the hot line at the end of this drive about a 15 - 20 minute ride. going back home i babied the car only going 40 and keepiing the revs at 2000 not above and the temp stayed at the line below the h but never rose.

any ideas, im at my whitz end, i really dont want to get rid of the vx but cant keep fixing things that dont solve the problem.
could it be the bolt if there are no gasses in the radiator?