Losing Tire Pressure

[bkay24]

Hi

I've got an 07 Yukon with about 115k miles. New Cooper A/T tires put on in Jan 2015 and swapped out a few bad TPMS sensors. Went back to the shop twice within a few months of new tires due to losing air pressure. They put all new bead sealer on.... still same problem.

Not as often in the summer, but now with winter temps, it's about every other week, I need inflate to about 35-37.. 2 weeks later I'm down to 25-27, but never gets lower than that for some reason.

Guy at Tire shop says wheel corrosion on the rim could be to blame, and is a "somewhat common issue" with GMC Wheels?

I do know that my current set of TPMS sensors aren't a matching set, but not sure that's a problem?

Purchase all new 4 TPMS?

Wheels really need to be replaced?

Any thoughts and opinions would be greatly welcomed.

Thanks in advance.

 

[sk1dm4rk]

If the tires are truly losing pressure, the sensors are not likely to blame and replacing them will not fix the issue. Now, if they were giving you weird readings and the pressure was actually OK, that is a different situation. I'm just saying I wouldn't damn them just for not being matched at this point of the troubleshooting.

Are all four tires needing air? Or is it always the same one(s) experiencing the issue?

If all four leak and they didn't leak before the new tires, it may be an issue with the tires. It is a heck of a coincidence that all four wheels are experiencing the corrosion issue to the point that you need to fill all of them up at the same time. They should also be able to tell you where the leak is coming from (bead, valve stem, etc....

On the other hand, if it is only one or so, then maybe it is the corrosion. You may want to try a different shop to see if they can fix it.

Replacing them is a money decision that I cannot make for you.


Good luck.

Mark

 

[bkay24]

Thanks for the response Mark.

All 4 tires are losing pressure, but at different rates of speed, none are consistent with the others. Warning light usually comes on when a tire gets below 26, I notice the other tires have dropped in pressure as well, and I inflate as needed. I haven't been able to determine any sort of pattern...

I only mentioned the TPMS Sensors wondering if maybe they were giving a bad reading?

Wheel corrosion never occurred to me until the guy at the tire shop mentioned. I asked the same question, "why weren't previous tires leaking", he basically said the tire had formed itself to the wheel and a brand new tire wouldn't fit the same....?...... again, this is just what I was told.

Defective tires also occurred to me as well... but all 4?

I do think a trip to a different shop is probably best, just stumped as to what could be causing this.

Thanks again.

 

[sk1dm4rk]

Responses inline.

Thanks for the response Mark.

All 4 tires are losing pressure, but at different rates of speed, none are consistent with the others. Warning light usually comes on when a tire gets below 26, I notice the other tires have dropped in pressure as well, and I inflate as needed. I haven't been able to determine any sort of pattern...

I only mentioned the TPMS Sensors wondering if maybe they were giving a bad reading?

I suppose that is possible, but the fact that you are adding air makes me think that this could only affect it a little, if at all. Are you using a manual gauge or one built into the pump? Try a manual gauge and put them all to the same psi and then drive for a day and check them with the manual gauge again and see which ones have moved and by how much. Make sure the conditions are equal (read: reading taken cold or taken after driving some distance, etc...).

Wheel corrosion never occurred to me until the guy at the tire shop mentioned. I asked the same question, "why weren't previous tires leaking", he basically said the tire had formed itself to the wheel and a brand new tire wouldn't fit the same....?...... again, this is just what I was told.

Defective tires also occurred to me as well... but all 4?

When I had my new shoes put on, the corrosion was terrible. The dude doing the work showed it to me and it was built-up in spots almost a half-inch. I am surprised the old tires didn't leak.

As for the tires, while it is a long-shot that all 4 are defective, if they are from the same batch, it is possible. By your description, if that were the case, they do seem to have varying degrees of being able to seal to the wheel (leaking at different rates).

I do think a trip to a different shop is probably best, just stumped as to what could be causing this.

Thanks again.

Good luck, sir.


Regards,

Mark