Top positive review
Well Constructed and Useful Tool
Reviewed in the United States on October 4, 2017
Decent bit of kit. I was impressed by the construction and utility of the tool. It consists of a thick-walled plastic tube capped at both ends by hefty rubber stoppers. A small amount of liquid reagent is added to the tube, which is then pressed into the radiator filler neck. The supplied rubber bulb is then pressed against the top of the tube and pumped slowly several times. This draws gasses from the radiator through a porous metal aerator, which bubbles them into the reagent. After a few pumps, the reagent turns from blue to yellow if hydrocarbons are present. There is a check valve in the bottom cap to prevent the reagent from draining out and another check valve in the bulb to ensure that it draws rather than pumps.
I successfully used this tool to (unfortunately) confirm that the head gasket of my 2003 Civic was leaking.
One difficulty I had was that it was easy to accidentally draw coolant into the tube (which ruins the test). I did this twice before finally draining enough coolant from the radiator to have a successful test. The instructions advise removing enough coolant to provide a few inches of gap before beginning the test, but I found that once the car warmed up, the coolant level increased to the point that it was necessary to siphon off even more. A design change that would help here would be to provide a floating ball valve (similar to that in a wet/dry shop vacuum) to prevent liquid from entering the tube. When I finally did a successful test, I was still concerned that the yellow color of the reagent, which is very similar to that of Prestone antifreeze, might be due to contamination from coolant, but I noted that the reagent in the tube was still at its original level (at the "fill line" marked on the tube). Afterwards, I experimented with adding antifreeze directly to reagent and determined that it takes a substantial amount of antifreeze to change the color of the reagent to pure yellow. Nevertheless, a reagent that turns to a different color than antifreeze would be a useful change, if that is chemically possible.
My only other complaint is that I discovered that, while the top rubber cap is designed to be removed for cleaning, the bottom cap is not. It is attached by an adhesive, but the adhesive is too weak, and the cap can be accidentally removed without much force. After it is removed, it cannot be reattached securely without using more adhesive. This should be corrected by either making the bottom cap removable by design, or by using a strong adhesive that prevents the cap from being removed at all.
Some other info: there is enough reagent in the supplied bottle to do several tests. According to the instructions, the shelf life of the reagent is about one year. Spent reagent from a positive test (that has turned yellow) cannot be reused, but it is not clear whether there would be any negative effects from reusing the reagent from a negative test.