fw991S

Help... mysterious loss of air pressure. Went to drive my car sun and I noticed as I drive, warning comes on saying it needs air. right rear shows 27psi, 3psi lower than where it was last when cold. I stop by gas station and add 6psi to be safe so im at 36/33(hot/cold)psi, vs left rear which has remained steady at normal 33/30psi.

Checked on it today, 3 days hence, and there's no loss of air so still holding steady at 33psi... wtf? What couldve caused this sudden loss? How does this happen and how does it not lose any psi over 3 days? Not diggin this at all...

i've read that valve stem could possibly cause this type problem but it's a head scratcher...

thanks for any input.

Sidvicious7

I had a slow leak on my valve stem.

Just to be crystal clear you are not leaking air from your valve stem, use soapy water to check for an air leak at the stem and core. Remove the valve cap and apply a bit of soapy water to confirm you don't have a slow leak.

LTP

cracked or bend wheels cause leaks too

worf928

And a nail.

On multiple occasions (across cars) I've had intermittent leaks due to nails/screws etc. If I parked with the nail "down" it would leak. Otherwise not.

spiderv6

ambient temperature change? has been all over the place on the east coast lately.

LexVan

The right rear tire LOVES nails. The front right tire stands them up. The right rear tire stabs 'em. After rainy days, the nails and screws wash over to the right side of the road.

Start looking for a nail in your tire. Get your big fat head under there, with a flashlight.

StormRune

I was familiar with the problem of the front tire standing up the nail so the rear tire gets punctured, but the analysis of rain moving the debris to the right is an interesting new concept to me. Good thinking!

Once in a Corvette I saw a spark plug in the road at the last moment. The front tire stood it up perfectly so that the ceramic end speared the face of the rear tire and imbedded in it. The next few loudly-thumping rotations drove it down flush and amazingly it managed to "plug" the hole long enough for me to get to a tire place. It seemed unbelievable.

I agree with LexVan that you probably had a puncture that then settled in and sealed itself.

Dan Nagy

Had the same problem with my tire this spring. It was a nail.

Code

Valve stem or nail gets my vote.

Churchill

This is so true. Have had THREE nails in my 991, every one of them in the RR.

OKB

your warning will go off at about 25lbs.You are saying you are at about 30, and that may be your hot temp. I think you are hovering to low on your pressures . put 36 lbs cold. If you cant figure out how to do it, put 40 lbs in them, let the car sit overnite and go let them down to 36 lbs. You could have a leak but you are too low with your pressures anyway

fw991S

whats odd is i havent had any loss of psi in 4 days. if its a nail shouldnt it lose pressure, however slow?