Add 1 V3 Catch Can teflon tape question

[itguy61]

I installed this and I am smelling the gas/oil smell after shutdown when the engine is warm. It is coming from the catch can. I have checked the hoses, the hose connections and made sure the canister is tight and the gasket is on right.

It seems as if the smell is coming from the fittings that are screwed in to the catch can that the hoses attach to. How many times did you wrap the Teflon tape around the threads? Is this supposed to seal the fittings? Would not having enough tape allow these to leak the fumes here?

Thanks

 

[Toddasaurus]

I installed this and I am smelling the gas/oil smell after shutdown when the engine is warm. It is coming from the catch can. I have checked the hoses, the hose connections and made sure the canister is tight and the gasket is on right.

It seems as if the smell is coming from the fittings that are screwed in to the catch can that the hoses attach to. How many times did you wrap the Teflon tape around the threads? Is this supposed to seal the fittings? Would not having enough tape allow these to leak the fumes here?

Thanks

Catch Cans *should* have o-rings to seal any potential leaks. Teflon tape can help, but I don't think it's going to totally seal it. Even so, it's worth a shot. Wrap about 3-4 times, make sure you keep pulling it tight while wrapping.

If your cans don't have grooves for o-rings, then you can use some sort of RTV sealant on the threads. This WILL make a mess of things, and it will be really hard (and messy) to unscrew, but it will seal it.

 

[oddball]

Huh, hard to tell how precisely those cans are set up.
Looks like the fittings should be ORB (O-ring base) fittings. There's a groove on the fitting where an o-ring sits, and a receiver groove on the can for the o-ring to snug into. The threads are straight cut (not tapered like NPT), so the threads will never seal. Don't put teflon on them. You can RTV them to make it permanent if you want.
If the o-ring is missing then it won't seal. If the o-ring is the wrong size then it won't seal. Who knows if they sized them properly. You should feel a real nice squish right as the fitting seats. If it zips right down to the base without feeling the o-ring crush then the o-ring is too small (cross-section).

Most cans use NPT (national pipe thread) fittings which is a taper thread. The thread literally jams, providing a seal. Teflon is only used to provide lubrication so you can get a good interference fit without galling the threads. It's in tape form because that's easier to deal with than the OG liquid. The teflon does not provide the seal. You should only use 3 wraps, max, of teflon. Now, really terribly machined parts that don't meet spec can be forced to kinda-sorta work for low pressures by putting a load of teflon, or using the paste with media in it.

This ignores the actual can part of the can. That always uses an o-ring seal.

 

[itguy61]

Huh, hard to tell how precisely those cans are set up.
Looks like the fittings should be ORB (O-ring base) fittings. There's a groove on the fitting where an o-ring sits, and a receiver groove on the can for the o-ring to snug into. The threads are straight cut (not tapered like NPT), so the threads will never seal. Don't put teflon on them. You can RTV them to make it permanent if you want.
If the o-ring is missing then it won't seal. If the o-ring is the wrong size then it won't seal. Who knows if they sized them properly. You should feel a real nice squish right as the fitting seats. If it zips right down to the base without feeling the o-ring crush then the o-ring is too small (cross-section).

Most cans use NPT (national pipe thread) fittings which is a taper thread. The thread literally jams, providing a seal. Teflon is only used to provide lubrication so you can get a good interference fit without galling the threads. It's in tape form because that's easier to deal with than the OG liquid. The teflon does not provide the seal. You should only use 3 wraps, max, of teflon. Now, really terribly machined parts that don't meet spec can be forced to kinda-sorta work for low pressures by putting a load of teflon, or using the paste with media in it.

This ignores the actual can part of the can. That always uses an o-ring seal.

The O-rings are there, the instructions say "seal with Teflon". They don't get any more specific. If I have to keep jacking with it I am just going to take it off as it is not worth the trouble. I can get down close and tell the odor is coming off the can. I have checked the o-ring on the canister and tightened it down. I have checked the hoses and clamps are tightened down. The only other place is the fittings. I took them off last night and put more teflon tape and checked the o-rings. I will see after my drive home if I still get the smell. I usually notice it when I pull into the garage and park it hot and come back out and smell the smell coming from the front of the car.

 

[itguy61]

Figured it out, the lower hose clamp had loosened, Ugh!

 

[Toddasaurus]

Hah! Glad it was an easy fix.