Fuel cap

[flyer170]

Where can I purchase a new vented fuel cap. I would like to replace my unvented cap. Any problem having two vented caps
Any thoughts would be appreceated
I have Monarch systems book marked but I didn't see new caps just their replacement system stuff.
Bob

[wa4jr]

Hi Bob....my 54 B model has two vented caps....both of which are leaking from the vent so I need to get two more caps myself I am going to get mine from Univair. I saw them in the catalog and seems the price is in the $35 range. If I were you, I would only put one vented cap on. Assuming a good main gasket, a non-vented cap cannot leak as can a vented cap if the vent works do not seal off. Don't mind so much the avgas stains, but I usually run auto gas, and that leaves a really ugly streak aft of the leaking caps

[flyer170]

John....Thanks for the reply. My vented cap doesn't leak but the non-vented one does. Go figure
Maybe I should just replace the rubber gasket on the leaking cap
I don't know if there are special requirements for that gasket.
Bob

[n1410d]

One vented fuel cap is sufficient. Mine is on the right tank and works great. As for new gaskets; I replaced mine a couple of annuals ago. They were not leaking but were starting to crack. When I went to remove the old gaskets they crumbled in my hands. Wag Aero Page 51 of the latest catalog P/N E-422-000 $6.95 each. By they way that gasket fit my oil filler cap too.

[JDH]

I bought a non vented cap (FC2646 @ $11.10) and a couple of gaskets (FC2651 @ $1.50) page 159 Aircraft Spruce. All fit good on my '52 B model. I haven't seen the vented caps, but they are only $11.85... JD

[flyer170]

Thanks for the responses. I looked up the parts in both catalogs, quite a difference in the price of the gaskets. $6.95 ea Wag-Aero and $1.95 at Spruce It probably is time to replace the gasket on the oil filler also, thanks for that tip.
My son and I are headed out tomorrow a.m. for a couple of days, headed west probably, SD, ND, WY, MT, NB maybe. What ever the weather gives us. We have our camping stuff along.
I'll probably order the stuff when I get back.
Bob

[planepilot1]

I will probably catch flak for saying this, but I was having fuel cap problems about a year ago and another member (name witheld to protect the innocent--right Goody?) suggested I check into fuel tank caps at the local O'Reilly Auto Parts store. I did so and subsequently purchased two of them (part # 10623) for $3.99 each + tax. They are the correct size, chrome (looks good) and ARE vented. They work just as well as the high dollar Cessna type. Now, they AREN'T technically legal and they do not have the hole drilled for attaching the retaining chain to keep them from falling off the wing when fueling, but again they work perfectly. I don't think you can add gaskets like on the official ones (might be able to), but @ $3.99 if a gasket were to start leaking a new cap would be the answer. You might even be able to drill a hole in the cap lug to put a retainer chain. I have not done so as I didn't think it necessary.

N6888A

[GAHorn]

Hmmmmn. N6888A, huh?

[Alterfede]

hey, what frank says about getting an auto fuel cap is good enough here since buying original fuel caps is really expensive due to the shipping charges to argentina, and the exchange and lots of other stuff.
My LV-FEH (170A) has a pair of old style ford falcon caps, with key lock. Altough they are not vented they work fine. ( hey came with the plane when i prchased it). I know that is it not legal anywhere, but, it is a good alternaitve for those who need a rapid solution and not costly of course. And a 1959 172 i´ve flown for years got a pais of heat radiator caps from a national ika jeep. They work really great, with vent hole and space for drilling a hole for the chains. I think we argentinian specialize in that stuff of fixing thins with wire!!. LAFF
My best regards for all 170ers

fede

[wa4jr]

I just purchased and installed a couple of new fuel caps from Spruce as JDH did. I got one vented and one unvented. Pleased to see that the price on the unvented cap dropped to around $7, but was surprised to see that the only difference in the vented cap was the addition on one small hole which I could have drilled myself in the cheaper unvented version

Although the caps look much better than the modern red plastic caps that the previous owner had installed, sad to say my right tank is still leaking overboard from the fuel filler port My left tank no longer leaks, so that is good I see that the black gasket that came with the cap has "wrikled" up like an accordian on the right side and may be the cause of the continued leak. I had purchased a pair of white gaskets for the other caps and will replace the wrikled black one with one of the $6 white ones. Maybe some silicone grease on the filler flange to help it seal. Has anyone else chronic fuel leaks at the fuel filler ports

[doug8082a]

John,

With just one vented cap, have you experienced a situation where the fuel is used at uneven rates from the tanks? When I had just one vented cap (on the right tank), the low pressure over the vent caused the right tank to siphon fuel from the left tank during flight. After an hour of flying I'd put 7 gallons back in, but it would take 2.5 or 3 gal. in the Right tank and 4 or 4.5 gal in the Left Tank. I subsequently installed fuel caps from Monarch Air. Both caps are vented and it corrected the prpoblem.

Doug.

[wa4jr]

Doug,

When I bought the aircraft in June, it came with two red late model Cessna vented caps. As I recall, the right tank fed faster so I had to feed from the left tank to even things up. With the new caps on, I have been on a long trip so can't say for sure how they are feeding. I only know that the right one is still leaking overboard from the filler neck even with a new cap...a vented cap. I plan to put the vented cap over on the left and see if the leak follows the cap. If the vented cap is the source of the leak...I will be tempted to verify that the factory venting system is OK and then go with unvented caps on both tanks to keep my fuel in the tank and off of my wings and horizontal stabilizer

[flyer170]

John.... Dosen't one of the caps have to be vented
Bob

[doug8082a]

There's an AD that requires at least one of the caps to be vented (right side). It doesn't prevent you from venting both, but is does prevent you from going back to the two unvented caps.

I had similar problems when I had the Cessna vented caps which is why I went with the Monarch ones. I'd prefer to put the originals back on, but that is no longer an option.

Doug.

[flyguy]

It is amazing how physics change over a period of 25 years! Cessna designed fuel tank caps in 1938 to use on their first general avaition airplanes. Caps that worked just fine until the mid 1970's, some brilliant faa geek decided that a change should occur just to make sure that no failure would occur! Results of that brilliant change are being talked about here. Uneven fuel flow, leaky tank neck sealing, fuel flowing out of tank vents and other neat side effects. My experience indicated that the only benefit to the $49.95 (*at that time) mod was into someones pocket.

I was fairly new to the "AD" phenom at that time and decided to go with two caps to balance the appearance, ie: two antenna and two new red fuel caps! Since that time I have not had any fuel starvation or uneven fuel flow( Of course I didn't have any of those symptoms before the AD!). What I do have is overboard fuel staining the back of the fuselage and wings. If the FAA knew this they probably would issue an ad to put the fuel tanks in the tail so that the risk of fire would be minimized!

Put the old style caps back on? I wouldn't recommend it but you would be suprised at the success if you did!