PeterUbers

Had this oem tire replaced under my wheel tire protection plan just a week ago and it was filled to 41 all around. Now only the right rear... The replaced tire (had a nail in it) is down to 38 with normal driving and others are at 41

They said (Benz) rim was ok

Thoughts?

sjb

I had the same issue when I swapped the tires to the HREs. It was one of the gaskets in the TPM. Replacing the unit fixed the issue.

gaspam

maybe the other tires 3 had nitrogen in them and when the dealer replaced and filled the new tire w/ regular compressed air? compressed air will seep slowly out of tire whereas nitrogen wont

PeterUbers

Good advice ... Will watch this one week and then take it in again

Vrodman

I am dealing with the same thing on my 2011, funny enough it is also the right rear tire. I just put on 2 new PSS on the rear about a month ago. Did not have the problem prior to that. I doubt the nitrogen theory in my case since both rears were done at the same time.

Also, My wife's 2013 GLK has the same problem on the left front. We just put 4 new tires on her car 3 months ago.

Same tire place (Americas Tire) did both installs. Hmmmmmmm????

Davidkuo0330

Hey Peter. Get a bottle sprayer and spray some water on the tire in question. If there is a leak, you should see bubbles. Make sure you rotate that tire so the water is sprayed on evenly.

Good luck.

robl45

This happened on my vette and also on my amg. With the vette people said the way the right rear tire spins can cause the sensor to loosen. Try to tighten it up a bit. With the amg. Both rears had nails but only the right rear was losing pressure. So if your sure you haven't picked up another nail. I would tighten the sensor a bit.

PeterUbers

Will try this tomorrow thanks man

PeterUbers

Can I do this from the outside or do I have to have Benz do it... Man am I glad I got that wheel tire insurance

PeterUbers

Man I had this issue on like three rims on a 2004 Acura TL aspec I used to have... Turned out to be bent rims

This is such an annoying problem

Davidkuo0330

Unfortunately, the TPMS is secured from inside of the wheels so tires need to come off if the leak is coming from the TPMS. Be sure to spray some water on the valve stem and see any bubbles are coming from there.

Good luck Peter. It might be a good time to put the wheels insurance to good use.

robl45

on the outside, you will see on the step there are some steps around the valve step, you can put a wrench and tighten a little bit. lightly of course, you don't want to break anything. When I did it on my right rear tire, the thing was relatively loose and tightened a bit with the wrench.

PeterUbers

Thanks guys

Just had them replace that tire last week and mount new tire cost $478 to them.

Will try the water trick and small attempt at tightening

Thanks guys

LFC09

a little detergent in the water will help with bubbles

PeterUbers

Mixed some Palmolive with water to a nice viscosity and applied to valve stem circumferentially

No obvious bubbles; didn't get a chance to apply to entire tire yet

Right rear (problem tire):
Pressure yesterday was 42.5
Today was 41.5

The left rear also dropped from 42.5 to 41.0

I presume some of this is just cooling of atmospheric air; regarding tightening that bolt/valve stem I don't have a socket deep enough to clear the stem to get to the hex bolt... Couldn't tighten it therefore

Will check all around after the drive to work and back

robl45

I believe I used an open end wrench

LFC09

Peter, those numbers don't sound significant.
Are you verifying with a separate gauge or using the TPMS numbers?
Scott

PeterUbers

Hey man, thanks for your input

I used two separate digital gauges which are similar in readings within 0.5psi with the Benz tpms

Also I have gone 24 hours with lots of driving and that rear tire is holding at 41 psi

Thanks again guys

Vrodman

Well, mystery solved on my E63! It was just a screw in the tire. Plugged and patched. Done.

If I find a screw in the wife's GLK tire, she is not going to be driving my car much anymore! I suspect she drove both vehicles somewhere near a construction area.

I should have known better than to let her drive the beast. At least no wheel curb rash yet. She scraped the hell out of one of her wheels the 2nd day she had the car. Ugh.

grimesch

I have a similar situation with left rear tire/wheel. Had to replace the wheel in December and put on Hakkapalitas for winter, and now that tire is typically 2-3 psi lower. Yesterday I had new Pirellis (summer) put on rear and after the drive home the same thing is happening. It may well be the TPMS on that new wheel. It doesn't seem to get worse, just that 2-3 psi.

PeterUbers

After another week of driving its down another 1 psi

Worth taking it in at this point ?? Just so annoying

joseyu

1 psi per week is probably within the normal range. Plus, the past few days has been colder so that would affect it as well. It is pretty common for bike tires to lose 10 psi per week and for the front and back tires to lose pressure at slightly different rates. I would wait and see what happens. If it starts losing 3-5 psi per week, then something is wrong.

PeterUbers

Good info thanks

Why do the fronts stay so damn stable?

joseyu

Have you checked to see if the needle valve inside the valve stem is tight? Maybe during the tire change, the needle valve got slightly damaged? This valve has to come out before the dismount and only put back on after the bead of the new tire has been popped. Maybe you can have a local tire shop replace that valve and refill the tire and see if anything changed.

cadeca

I had this same issue with the passenger side front tire on my SLK. New valve stem was the solution for me as well.