Topping off Tire Pressure - Valve Stem Blow Back

[Vanteer]

I decided to check my tire pressure today, usually check it every 2-3 months. I keep the tires at 40 lbs, and my car indicated 38/39 lbs, so time for a slight top off.

I got out my air tank, and 3 out of the four tires I got blow back, as if I had removed the Schrader valve. Two of the 3 shut off after 1/2 second or so. But the 3 tire, each time I removed the fill hose, it just free flowed air out. I had to keep adding back air, I think 4 times before the valve shut off. I was worried that it would not shut off, and I would end up with flat tire.

I have never in my 50 years of filling up tires had this happen. Now I am wondering what will happen next time......

I did a few searches, did not find any posts like this. Anyone else have this happen?

Vanteer

 

[GLM3]

I just added air to all four tires today and didn't experience what you are describing at all.

 

[SigNC]

never had such happen

 

[sduck]

Do you have any kind of aftermarket tires or something? Otherwise I'd suspect user error. Having a tiny bit of air release as you're pulling off the hose is normal. If you're getting a lot of blow back under normal circumstances it's usually because you're not pulling off the hose efficiently. What kind of "air tank" are you using? What kind of connector does it have? Maybe it's worth considering updating your equipment.

 

[Vanteer]

Stock tires. I have used this air tank and hose for many years. This was not the normal slight little puff when removing the push on filler end. I have filled my tires hundreds of times over my 50 years of filling tires. I have a few hose ends, I will try a different one next time. I could feel the air shooting out of the valve stem, so for some reason it was not closing normally.

Anyway, thanks for your thoughts. I did not figure this was a wide spread problem, or someone else would have posted by now.

 

[lolder]

I think it's called a Shrader valve and is usually replaceable by unscrewing it and screwing in another during which time you will lose most of the air.

 

[GLM3]

I think it's called a Shrader valve and is usually replaceable by unscrewing it and screwing in another during which time you will lose most of the air.

It is called a Shrade valve and the valve cores are available at any parts store along with the tool to replace them. I keep extras around because it not unusual for them to leak. The OP may want to get the tool and check the valves are tight, or even loosen and retighten to blow out any dust that may be causing the issue.

 

[TjckTock]

For you to have issues with three out of four suggests vandalism IMO. Someone loosened all your valves. It is not unheard of to have these removed as a form of vandalism. Maybe the culprit didn't want you to know where it happened so they just loosened them.

 

[TjckTock]

You didn't by any chance install gunk or any other of those other miracle flat repair/prevention in a can products? Didn't think so. Just checking (had to ask).

 

[Vanteer]

You didn't by any chance install gunk or any other of those other miracle flat repair/prevention in a can products? Didn't think so. Just checking (had to ask).

No gunk in the tires. Schrader valves all tight. Car is parked in the garage, changes of vandalism very slim, but good thought. I wonder if any of the sound dampening material could have effected the closing of the valve. Two out of the three the blowback was less than a second. The third took 3 or so shots of new air before it finally stopped free flowing.

By then the air pressure was up to 43 lbs. I was able to bleed out 3 pounds normally. No sticking at all.

Perhaps my air filler fitting is worn out, and it’s pushing the schrader valve in to far? It’s probably a 20 year old air tank and hose.

its a mystery.

Thanks for all your ideas.

 

[KenC]

Maybe change the valve stems.

 

[lolder]

The valve stems are probably part of the TPMS sensor. Just about every time I leave home I tap the right steering wheel button and say "Show/display tire pressure". It takes about 1/2 a block of driving for them to switch on. The displayed pressures agree within a pound of my mechanic's digital gauge

 

[skygraff]

Some dirt in the valve?

Caps aren't hermetically sealed so stuff can sometimes get up and under. If there's dirt, try some compressed air or a vacuum.

 

[Feathermerchan]

Model 3 is recommended 42 PSI I think. I run 45 or so for better mileage and more responsive steering and a little more margin for preventing potholes destroying tires and wheels. That said I have never heard of this either except on some old bike itres that were sticking. I don't know what the proper lubrication is.
Have you filled the tires from this tank before? Maybe some rust in it? Just guessing.

Finally, I replace my OEM tires with good Michelin tires and usually only have to add air when the weather cools off.

 

[jonnyogood]

I experienced the same thing on one tire this morning. I just screwed on the cap to make it stop, and will watch for any pressure drop.

 

[Feathermerchan]

A drop of oil in the Schrader might help if it's sticky for some reason. I don't think it could hurt.
I have not experienced this or heard of it happening.

 

[Gauss Guzzler]

Maybe you just have a rusty air tank and the crumbles are getting pumped into your tires?