NAPA Combustion Products Coolant Test - Coolant Recovery Tank???

[coolnesss]

I got a NAPA combustion products test for my 2002 ETC. The instructions state to put the instrument into the radiator cap opening. There is nothing said about a recovery tank.

The instructions indicate that it is measuring exhaust gases, that the engine needs to be warm and running, so it's getting gasses from the coolant as it flows.

With the recovery tank, is there enough circulation of coolant through it when the motor is warmed up and running to produce gasses to measure? There doesn't seem to be any movement at all of coolant in my tank. I checked the bypass and it's flowing.

THANKS

[JimD]

I will bet what you are calling a "recovery tank" is what GM calls a "reservoir".

There will be a pressure cap on your reservoir (probably including a ratchet mechanism similar to your fuel fill cap).

So yes, you can sniff for combustion by-products in the reservoir. In fact the reservoir is the only location where you can gain access to the engine cooling system for routine service.