SC430Fan

I've read all threads re: tires, rims, leaks, etc. My 2002 SC430 is driven 2 -3 times week and has 30K on it. January '08 I replaced run-flats with high-end non-RF Michelins sugg'd here. Ever since, tires have lost pressure. So far, I was told front pass. rim (orig. factory chrome) had a crack, that was fixed, but tire still loses pressure. Rear Driver's tire supposedly punctured at 2 weeks & replaced..but still loses pressure. All tires & wheels were checked & rotated, now 2 still leak in new positions. According to Dealership & Tire place familiar with SC430's, my Valve stems and sensors are fine (TPMS works fine), tires are good, rims aren't cracked, but tires go soft. Yesterday a Tire place that does only Lexus & Toyota just told me "invisible corrosion" on rims makes moisture collect where tires seal to rims and this causes slow leak!? I'm in So Cal, it's dry and warm and this sounds wrong, but I'm no expert. Anyone hear of this? Any different explanation or solution?? The rims look perf., I hate to buy new ones not knowing if that's the problem. I'm out of ideas. Thanks all!
Marty

PHXSC

Welcome to the forum.
Most tire places have a water tank where they can submerge the tire and wheel and check for leaks. If they're going soft, you have a leak somewhere, and the water tank test should find it. I've seen them actually over-inflate prior to submerging to get a slow leak to show up.

tfeni52355

SC430Fan,
I have an '02 SC with 23K miles and have been battling the same problem since purchasing a year agao. My SC has Pirelli PZero Nero non-runflats on it and they were new when I purchased the car.

Here's what I have done to find the leaking:
1) take some Windex and spray around the rim where the tire meets the wheel. Wipe off the excess.
2) Wait 5 minutes and see if there there are any bubbles around the rim.

Chances are you'll find some small bubbles which are the leaks.

I took my car to a local Tire Kingdom and they broke the seal around the rim, inspected each wheel and tire and then used a sealant around the rim to keep it from leaking in the future. I did this for three out of four wheels and need to go back and get the last wheel done.

I since have to put air in the tires about every 10 days. I use a Black and Decker Air Station ($40 at Lowes). It's awesome since it runs on 110V, has a pressure switch which can be set to automatically shut off the compressor at the same pressure each time. I know this is not the cure but it does seem to be more manageable.

I plan on replacing the wheels this year so I'm not going to drive myself nuts trying to solve the problem.

Hope this helps and Good Luck!

lexus ASM

The problem is the combination of non runflats and factory chrome rims, all or most lexus factory chrom rims leak because the bead surface is coated in chrome and does not seal properly over time. The ultra stiff sidewall in runflats helps to secure the tire to the rim at the bead even theres no pressure in the tire... hence run flat.
So when you use a soft sidewall tire on a chrome rim you remove the support that helps keep air locked in... SC wheels are also made out of pot metal(not really)... never seen so many bent rims as I have on these cars... And rear camber wear(for a stock vehicle).

texsexlex

iTrader: (3)

...well I have the run flats on my 02 also...I experienced this off and on,for about 6 months!!! I'm from the old school and had the tire,in the tank test done...but no bubbles!!! I was told possible cracked rim,valve stem,wheel beads,etc..,..but what was crazy,I could put air in them and they would hold afterwards !!! I finally had them taken off and a thin coat of sealant,put around the bead edges...this has helped.In texas the temp changes so much,I thought it may be from the drastic weather changes also...different temps and pressure everyday.Not sure,but haven't had any problems in the last 5-6 months.They just need to hold on,for another month or so....then I'll be looking to jump into some 19's or 20's !!! ed

Pearlpower

iTrader: (2)

Many good suggestions posted. Also, to further, yes, a wheel can have excessive porosity which will allow a very very slow leak that would ordinarily not get detected by the water method. Not common but it does happen. I know GM put out a TSB on it recently on one of their vehicles.

JTMav

My understanding is that chrome rims are the problem, not just Lexus. My son drives an old 2000 Chrysler 300m with factory chromes and they exhibit the same problem. Just put 4 brand new Blizzak snows on them and they still lose pressure over time. He needs to top off around every 7-10 days.

JTMav

igorxx

I didn't have trouble loosing tire pressure until I change my 02 rims for BBS. Loose about 5 lbs every 2-3 months in one wheel. I just bought an air machine like tnifi did and check them every couple of months. I also run my tires at about 35lbs. They are only down 5 lbs when the indicator shows on the dash.

killer

I have two Ls's a 400 and 430 with Chrome wheels. I have been dealing with this problem for some time. For me its a leak out of the sidewall. I had a local repair shop remove the tires off the rims and use a 3M brillo type pad on the sidewalls of the rims and then seal them bead of the tire with a sealant. They sometimes had to scrape the coroded chrome off the rims. This seems to do the trick. I did have to go back a second time since the leak was not completely fixed the first time.

What I think is happening is the tire shops use a water based lubricant (soapy water) to seal the tires to the bead. This will corode the chrome on the rim where the tires bead contacts the rim. Some tire shops use a different lubricant (animal based, I think) and that will not corode the chrome on the rims.

The discount tire place here in Indianapolis area told me they cannot fix it and wanted to sell me new Chrome wheels. I can only imagine what that will cost. I dont think Ill be going back there much.

Wheel Dr

Chrome wheels tend to lose their smoothness where the rubber meets the chrome,this is why you see second hand chrome wheels for sale all the time, people get tired of fighting them. Mercedes had a big problem with chrome wheels in the past and that was due to flaking of the chrome. The whole gist of this is while chrome may look stunning when you first mount them, you will put in extra time polishing and airing them up more often. Personally I think the graphite look is nice even when they are a bit dirty, and they don't leak.

TXFM

You should also have the rubber mounting groments for your tire pressure sensors (inside the wheel) checked. From day one, my car had problems with them and when I finally disabled the whole TPM system, the problem went away.

tfeni52355

I went out of town this week for 6 days and before I left made sure the tire pressures were up on the SC for my wife. Came back Friday night and my wife said the car was driving terrible. Sure enough, yesterday morning I checked and three of the four tires were way down on air pressure. One as much as 15 PSI.

I took the SC to Tire Kingdom and they agreed to check it out since they had originally sealed the rims/tires for me before. Well they called me back said they worked on two of the three wheels and couldn't stop the slow leaking at the rim/tire seal. I asked if it could be the tires and they said the tires were fine, that it was the wheels. The tires are Pirelli P Zero Nero M&S non-runflat summer tires with 9K miles on them.

My questions are:
1) Will the summer tires leak more air in the winter temps? The SC sat in the garage for several days since we had some snow and low temps for a few days.

2) Would a can of fix-a-flat (Slime?) help possibly? I plan on upgrading the wheels and tires so I'm not concerned about "ruining" the rims/tires by putting the fix-a-flat in.

Any suggestions welcome.

Thanks

jonra99

I have the same problem on my 02 SC430 - 28K miles with the same tires - P Zero Nero M&S non-runflat and stock wheels. I've had these tires for two or three years I think. I drive the car mostly on the weekends. Two tires I have to add air every 3 or 4 days to one week in the winter and every 10 days to two weeks in the summer. I gave up taking it to the Lexus dealer to solve...I even put in nitrogen air... They tried all the things mentioned above, so I just live it, because I plan on installing new 19 or 20 inch wheels & wider rear tires. I'm convinced the problem is the crappy wheels. I only learned recently from this thread the stock wheels are chrome? That was a surprise to me. Two of my wheels went out of round easily, edge chiped (maybe why can't hold air), & my 5 spoke inserts discolored... otherwise I love the car...

tfeni52355

jonra99,
Thanks for the feedback. I thought maybe I was the only one battling this issue! The guys at Tire Kingdom did a great job for me and didn't charge me since they hadn't fixed the problem. If nothing else I felt I was being treated fairly. Guess I'll just have to use the B&D Air Station pretty often until I can get the $$ together of the new wheels.

I'm pretty sure the stock Lexus wheels are an alumminum alloy and not chromed. The finish is machined or painted. I have used some sliver/aluminum colored paint to touch up the curb rash and it matched almost exactly. That wouldn't be the case with true chromed rims.

PERRYinLA

This is a common problem with chrome wheels- see this web page for more details and pics of the issue: http://www.whlworx.com/Chrome_Wheels_Loosing_Air.htm

I had a lot of "Chrome Cancer" corrosion (and resultant leakage) on the inner lip of all of my wheels, but I was able to fix it (or, at least, stall its return for several years). It just takes a little time, a cooperative tire shop and elbow grease:

Have the shop remove the tire and take the wheel home. Using a circular wire wheel on a drill, remove all the flaking chrome and corrosion. Then use a grinding stone on the drill to grind the lip smooth. The important area to smooth out is the ~4mm strip where the tire seals against the lip. The rest, not so critical to be smooth but grind off all corroded areas near that strip so it does not spread.

Finish off the prep with some 100 grit sandpaper and then spray several coats of bare-metal primer (Krylon 91317 Ruddy Brown Sandable Primer or equivalent).

Most tire shops will not want to bother with this since, depending upon how bad the corrosion is, this takes 30-60 minutes per wheel. But it was worth it to me, despite the hassle of shuttling back and forth to the tire shop.

(And, if you time this to coincide with the purchase of new tires, the fix is free!)

I've gone ahead and posted more complete instructions on how I did it (with pics) in the following thread in the tires wheels and brakes forum:

https://www.clublexus.com/forums/the...with-pics.html