The International Cessna^® 170 Association

Hello all! I am getting the smell of fuel whenever maneuvering in flight. I have partially pulled the headliner to check the hose near the T and vent but haven't seen an issue yet. My first plan is to look for an obvious leak and replace the tubing near the T and vent. Anyone have any experience with fuel smells like this? Do you need to drain the tanks if you are only replacing the vent line tubing? BTW '52 170B. Thanks in advance. Skip

No you don't need to drain the tanks to replace the tubing in the vent line.

While it is a good idea to check for fuel leak sources when fuel is smelled it is not unusual, in my 170 anyway, to smell fuel when maneuvering. If I recall older discussions others will collaborate this.

Just noticed this for the first time today myself, experienced "moderate" turbulence between Whitehorse and Haines Junction (30 knot surface tailwind meets 30 knot winds aloft coming from 10'o'clock) smelled fuel but noticed nothing else out of the ordinary. Been in turbulence before and never smelled fuel in either my 170 or old 172's I used to fly. However, I had just topped the tanks off about 15-20 minutes previous.

Any time that a fuel smell occurs in the cabin, I immediately suspect the rubber hoses on the cross cabin fuel vent line.
With full, or nearly full tanks, this line will flood with fuel when the aircraft nose is lowered in flight. If the connector hoses are loose or deteriorated, the cuel smell can become very strong.

I had the same problem, and had to replace the rubber fuel lines associated with the original fuel vent. The leak was near the wing root, if my memory serves me right.
Cheers Eric

I have exerienced the same smell occasionally, sometimes landing, and always before startup. I assumed that it was the fuel sampler that I was smelling before startup. Turns out my fuel selector has been weeping around the top gasket a little, just not quite enough to drip. You might want to the inspection covers and have a look at that to.

Well I replaced the two rubber hoses at the T by the vent. They were really brittle/cracking. I will also take a look at the fuel selector. Gonna try it out tomorrow.

I have a similar problem with fuel odors and have concluded its caused by leaking (Monarch) fuel caps during turbulance or when taking off with full tanks.

The fuel runs down the wing near the root and I can smell it in the cabin.

I've checked the hoses and they're not leaking.

Dale

After you have eliminated everything else. Pull the cover and check the top inboard part of the tank. If the tiedown straps become loose, the tank can rub on the edge of the wing spar and eventually will develope a hairline crack. It will seep as described. Been there done that.

Another source of fuel odors can be when landing short with full tanks. Fuel will regurgitate out of the gooseneck vent onto the upper windshield, which is not as "sealed" as one might think. (But the most common reason is dry/cracked interconnect hoses in the overhead above the headliner. Smoking is hazardous to your health.)

Replacing the hose connectors on each side of the vent did the job! did a lot of maneuvers and a cople of landings.. no odors. Thanks for your input. Problem solved!