My tires came from the dealer (Conti ProContact for 18" wheels) with 42 psi in the front and 46 psi in the rear when I leased the car back in September. Up until last weekend, the pressures were high. Last weekend, I got the headlight bulbs changed in my car. Unknown to me until yesterday, the dealer also rectified the tire pressure, although they never wrote up paperwork for changing out my bulbs, so I have no proof that they reduced the tire pressure to 32 psi in the front and 38 psi in the rear.

I got home today in the early afternoon. I parked the car in the garage and came back 4 hours later to meet my wife at the dealership. [The panorama roof on her GL (the back piece) was not clear and had some weird scratching/peeling issues. We wanted the roof replaced, so MB told us to bring in the GL so they can take a look at it in person after the manager sent them pictures.] Anyways, after I pulled out of the garage, less than 15 seconds later, my tire pressure warning came on. The rear passenger tire deflated to 18 psi. 1 minute later, 17 psi. Seeing no damage to the wheel and suspecting an error in the PSI monitor, I drove 4 miles to the nearest gas station as slowly as possible, although the tire did bear the brunt of a gazillion potholes and steel plates (there is a lot of construction going on where I live in west L.A.). I got to the gas station and inflated the pressure to 40 psi to compensate in case the tire deflated again. 2 minutes later, the pressure dropped to 37 psi. I took the car to the dealer (by now, my wife had already completed the paperwork, etc and left the dealer). I showed my S.A. the wheel. He couldn't see any damage on the tire itself. Since the service department was closing at 6 pm and I arrived at 5:30 pm, all the techs were already cleaning up and getting ready to go. The dealer told me to bring the car in the morning and inflated the tire back to 40. 2 minutes out of the dealership, back to 37 psi. Ughhhh....so I took it back and had the roadside assistance man replace the tire with the spare wheel (although in the process, he managed to create a few clear coat scratches on my black car as he rubbed past the car in his dirty pants against the dust and grime on my car...aka he caused marring). I was thankful that he was doing the tire swap, so I thought "whatever" and will forget that. Anyways, I left the wheel and tire at the dealership and took a picture of the rim in case the dealer scratches the rim in the process of inspecting the tire, removing/replacing the tire in the process, etc... One scratch and they're refinishing my wheel at no charge

Anyways, I am in a bit of a dilemma and have some worries. They don't know what's going on with the tire yet, because they didn't see any damage to the tire itself. The dealer showed me a recent WIS document that prohibits MB dealers from patching tires (apparently, a family in San Diego was driving in a Mercedes with a patched tire and they crashed; two of the family members died because the patch came apart on the tire and so MB stopped patching tires). CRAP.

If there's no damage to the tire, will I have to pay for a new one? Any experiences? If there is damage, should I get it patched up at a tire shop? A new tire is expensive, so I want to avoid it. I'll update you guys on what goes on as I never drove through potholes at high speeds...but maybe a construction nail slipped into the tire?

I'm also worried about the dealer scratching my wheel, swapping out my wheel with an old one from a preowned E class. Has anyone had experiences with MB dealers scratching the outer edge of the rim after replacing tires?
I know that some dealers have automated machines to replace tires on rims, but I'm worried that the machine or the mechanic will put in some scratches on the wheel if the tire needs to be replaced or removed to be inspected properly. I know I'm thinking way ahead and preparing for the worst, so if they scratch the wheel, even a small clearcoat scratch, should I complain?

This whole experience is a bit strange...I hope the dealer doesn't keep the wheel and say, "what flat tire?" I never got paperwork from my SA since the service department was closing and the roadside guy never gave me a receipt...I'm doubting whether or not it was a good idea to leave my wheel in the dealer's busy shop where it could be tossed around.

 

It is very common to get scratches on wheels when changing tires but dealers are generally better than tire stores.

There are only a few places where a tire can leak.

A punctured tire, at the place where the wheel meets the tire, the valve stem or a damaged wheel. Most common of course is a puncture.

Tires with punctures in the tread area have been repaired from the earliest days of tires and, if done properly, pose no safety issue. Because you cannot visually see internal sidewall damage, BMW dealers will refuse to patch run flat tires but most tire places will as long as you can assure them that the car was not driven with extremely low pressure.

In your case, I'd say that it really depends on what the problem is and the age, condition and mileage of your tires. If there is a puncture within the tread area, your tires are otherwise in good condition and you have a decent tire place available, then I'd take the wheel back from the dealer and get it patched. Tire patches seldom fail if patched/plugged from the inside.

Continental tires come with a tire warranty that covers road hazards as well (note - this is a Continental warranty and not a MB warranty) but at this point it is academic until we know what is wrong with the tire or wheel.

 

I've never leased a car so don't know how **** I'd be about wear and tear that occurs with normal maintenance. As CEB noted, scratches are common when changing tires. If the wheel is scratched upon return, let your SA know about it so at least it can be noted -- I would guess that would give you documentation to dispute any extra charges at lease end.

As for patching tires, I've never had an issue with it. In fact, I picked up a 1.5" drywall screw in a rear tire a couple of weeks ago and simply took it to the local gas station. The tech couldn't get leverage while the wheel was mounted so had to remove it. I was there the entire time and he was very careful -- not a scratch on the wheel. He yanked the screw, put in a plug and remounted the wheel. Took about 5 minutes and $10.

 

Here is a photo of a typical plug/patch. It is inserted into the hole left by the nail or screw from the inside of the tire. Accordingly, there is no way that the patch can detach from the tire during driving and the repair is permanent. In general, only punctures in the tread area can be repaired.

 

Is it true that plugging a tire will reduce it's speed rating? I've been told this many times, but have not had to have had a tire plugged.

 

No. Some German tire dealers will refuse to patch W and Y rated tires (speed rating of 168 and 186mph) for liability issues, this does not hold true in the US.

Most of our tires are V rated (149mph) and since the highest speed limit in the US is 75mph it really is academic.

 

Thanks for the info, CEB. I will make sure there are no scratches on the wheels during installation as much as I can. Apparently, there was a tear in the sidewall of the tire, which I didn't notice. The dealer is charging approx. $416 including mounting, valve stem, and a new tire...It's strange because I never hit potholes at more than 10 mph and take more caution in my E than in my GL, which never had a flat and I drive that thing over potholes at 20 mph. I bet once I stop being so **** about potholes, I won't have to deal with flat tires

I don't want to patch up the sidewall, but since there's no damage to the vehicle or visible damage to the tire, do you think warranty might come into play? After spending $500 on a new windshield (deductible) and money on car washing equipment, those ugly Philips bulbs, and other stuff, I don't want to spend so much money...

 

Sidewall damage cannot be repaired, but:

Why a new tire stem? Your car has TPMS (you are in the US, correct?) so the most they would need is a rebuild kit for $20.

At this point it is probably too late, but here is the warranty information for your tires. Depending on the cause of the damage, it may have been covered. If the dealer has not yet put on a new tire, then take the tire to a Conti dealer and ask them to file a claim. If your dealer is good then they will do it too.

I've found Conti to be very good with warranty claims and I've seen then often give the customer the benefit of the doubt. Good luck and keep us posted.