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Tire pressure

I have a 2008 Honda Accord with a problem that has my mechanic stumped. I thought there was a slow leak in at least one of the tires so I took it in to have them remounted. He couldn’t find any leaks so he put 33 lbs of pressure in each of the tires and took the car home that evening. The next morning all four tires were at 20 lbs of pressure. Any ideas, besides gremlins?

Is this a puzzler question? Did the temperature drop overnight by say sixty degrees?

Different tire gauge? Or same gauge?

There was a rash of bad Chinese valve stems, if all else fails try having them replaced.

It’s not a puzzler question. The temperature may have dropped by as much as 20 degrees. Not enough to account for this difference.

Good suggestion. Any idea when these bad valve stems appeared? I had snow tires put on last November and the stems may have been replaced at that time.

If not the valve stems, then all I can think of is a set of porous wheels. But 12 lbs overnight should still show bubbles in a soapy leak tank (inflate to max pressure listed on the sidewall first).

And bad valve stems will show leaks. The problem was typically sudden failure.

I can’t believe that all four wheels could be porous after only 2 years. If there is a general problem with Hondas of this year, you’d think that there would have been a recall.

Does anyone think that the sensor that sends the low tire pressure message could have anything to do with this?

Agree, wheels are unlikely, but it’s leaking somewhere, it’s either tire, rim, stem, or at the bead.

You are referring to the pressure read on a gauge, not the sensor, right? And the sensor is 100% inside the tire, it shouldn’t be able to cause a leak.

What measured the 20 PSI? The mechanic’s gauge, a different gauge or the sensor in the tires? It seems too much of a coincidence that all four tires would lose the same amount of air overnight. Try a new gauge, reinflate the tires, and check again to see if you can repeat the air loss.

Ed B.