Carbon Monoxide

Delta Fox

Delta Fox

Well-Known Member
Anyone have any insight on a CO leak in a 1961 C-172? I have a digital meter indicating 20-30ppm in flight. I have disconnected the heater hose, and I'm still getting it. It's enough to get an annoying headache and feel wiped out after flight.
 
Step one would be to not fly it anymore until the cause is found and eliminated. I know of someone who succumbed to it.
 
How old is your exhaust? 1961 172 so a Continental O-300? Pull your cowl and look for exhaust leaks (white or grey powder on things near the exhaust.) Finding the crack may require close inspection with a magnifying lens or even dye penetrant in some cases. Worn out slip joints or gaskets may also contribute to leakage.

Get some sealant (RTV or the like) and make absolute sure anywhere anything passes through the firewall is well sealed and make sure your door seals are in good shape.
 
I've replaced the exhaust cans on both sides, and any risers that had holes/leaks in them. I'll check the firewall and door seals. Any chance the boot covering the nose gear linkage could be a point of entry for CO?
 
Not sure what the older 172 ones look like but if they're like the later model ones then yes, that could let it in too.

They probably are if you replaced them also, but make sure the stacks are the right length, if they end too close to the cowl the exhaust ends up back inside it sometimes.
 
replaced the steering arm boots, which helped some, added some wx stripping to doors, which helped a little more. Still getting 15-20ppm.
 
I highly doubt you'll get it below that value no matter what you do...

Perhaps your headache is caused by something else?
 
I added some wx stripping to the door seals and reconnected the heater hose. The CO dropped to 0ppm, however it's a temporary fix. I need to get a permanent solution.
 
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