Wujohn

Agree on the temperature changes - it does make a big difference. The soapy water spray works great - that is what many use when finding a gas leak around a gas meter (after using the sniffer). Works just as well for an air leak in a tire.

IXLR8

From the Owner's Manual: 18F or 10C = 1.5 psi. Easy if one side is facing the sun. Tires are black.

There is a seal at the TPMS to rim junction on my other car. Maybe the hold down nut neets tightening.

Carrera-T

I was going to recommend tightening the schrader valve. Sounds like you did that. Had a similar experience once and that seemed to do the trick.

Need4S

Probably this. Don't overtighten the holddown nut on the valve, though. You will deform the O ring and it can leak worse.

IXLR8

There are torque specs for that nut. I installed a set of TPMS sensors in my winter rims on the Acura. Continental, VDO, etc make them. They are in the low in.lb. like 70.

Bob Z.

Yeah, cold here for FL! Only 1 tire was low so it cannot be the cold. I just checked the tires again and both rears were stll at 40psi so I am baffled. I cannot see this resolving itself since both the car and my gauge showed a decrease. So I rolled the car a bit so the tire is in a different position and I will check it again tomorrow with my gauge and while driving. Stay tuned.

Cyberbug

A little spit on the finger and then valve will do that trick just as easily ......LoL

Penn4S

Hope you find the gremlin. But it still could be temps. Up in Philly when the weather shifts I lose air very inconsistently in the 4 tires, location in garage, proximity to the door, etc... Good luck with the search.

SH2

dribar

Stevelev

LexVan

Here's a trick. Use your cell phone camera. Snap a few pictures of the tire, and blow them up to look/see. It helps you to see the far inner edge. You may have had a nail/screw for a l o n g time, and wore the head off of it.

Bob Z.

I just checked it again and it is still at 40, right where I left it and that is after rotating it a few times. I live in a condo and do not have the tools to take of off but I do have soapy water, which is great since I do not like to get my hands dirty. We are going out to dinner later and I will see what the car says and report back. Could it be that since it is cold (upper 40s) and the concrete is even colder in the garage a hole could have closed up, and when I drive the tire heats up and it expands allowing air to escape?

Speaking of tire gauges, what is the best? IXLR8 mentioned a Longacre and Suncoast has them for $28. I have gone through several the last few years since they work at first but start flaking out thereafter.

LexVan

^can't beat Longacre. Quality product.

Psorcery

Bob I had a similar issue which ended up getting worse as the weeks went on. Had to use the tire inflator kit a few times when the car sat for 4+ days.

Tire shop found 2 nails in the tire which I was never able to see.

Found a big open area and obliterated the rears and then I replaced all four keeping the fronts aside as spares.