Iceknyght

I seem to be having a problem on my wheels, they don't seem to want to hold air! I have the stock 18" Fanblades (although, they did not come with my car) and have had them on my car for about 6 months... The pressure seems to drop in mainly 3 of the tires after a few days... Starting at 32 psi, after a couple days, 3 of them are in the 20's... Driver's front: 24.5, Pass. Front: 29, Drivers Rear: 31, Pass. Rear, 24.

I have had the car into the dealership a couple times now because of this (and is there again right now), and they can't seem to find any reasons for the pressure drop... The tech showed me how he did the water/soap test and even checked the entire rim (including the inside) to see if there was anything causing the problem, but so far, nothing...

Anyone have any ideas to what might be causing this?! I am tired of having to fill up my tires every week...

SD CALSPCL

Just my .02....but it sounds like the valve stems may be slowly leaking. They have a core in them that can be tightened. Have the tech check the stems, and forget the water/soap on them. If it is a very gradual leak, it might not show up. Ask him to check the cores and reseat them.

As a last resort, ask them to replace all four stems. Even if you have to pay a few bucks, the piece of mind is worth it. I haven't seen a valve stem problem for many years, and thought their reliabilty had been greatly increased. Do you know if these are the original stems from the factory?

And, it may also be defective wheels, but the odds you received four bad wheels has to be astronomical. I had one wheel that had a small crack and leaked like a sieve. But again that was an aftermarket wheel and several years ago.

If the valve stems pass, ask them to submerge the entire tire/wheel assembly in water and look the air bubbles to ascertain of there are any cracks or defects in the wheel itself.

Good luck.

Iceknyght

I asked that the first time and they said one was a bit loose, and tightened it, but the rest looked fine... I may just asked to have them replaced though if they don't find anything this time... As far as I know, they are the stock stems...

And I doubted it would be 4 bad rims/tires too, unless they were made on like a Friday at 4:45 right before a 3 day weekend... LOL!

I think that's what they did this last time... Cause the tech thought it might be a bad wheel, but didn't see anything there either...

Might gut (like you) still tells me it's the stems...

CooBra07

I had a similar problem with one of my truck tires...I tried everything and could not find the leak...sometimes small air leaks are hard to detect, so I took it to a tireshop and they were able to find it. This is how they did it.

All they did is fill the wheel with about 65 psi and 'waalah' there it was...It turns out the extra air pressure was the key. The leak came from this hair line crack on the inner part of the wheel. I only filled the tire with about 35 psi..not enough pressure to detect such small leak it turns out.

That was my experience......

Iceknyght

Thanks!

It is still an ongoing thing for me... I took it in, they haven't been able to pin point the problem yet (I may suggest your way to them!), but we are moving forward... Thursday, I brought it in and they filled all the tires to 32 PSI and measured it with *their* air gauge... This morning, I brought it in and 3 out of the 4 tires were down to 30 PSI using the same air gauge... He is going to have me bring it back in Thursday morning and see if they have gone down anymore... At least this way, he is documenting the air pressure dropping (and confirming I am not crazy! LOL)... I am not sure what will happen if it drops more... I am sure they are getting tired of seeing me come in every few days though! LOL!

FLAstangx3

probably a strange answer. and wordy too. BUT. You said "..Not originally on car". Soooo, did you have to mount the tires? on the Fanbades, or were they a complete set? I ask because, I just put Nitto Redlines on my stock Fanblades. The TPS system was attached to the inner stem, so I opted not to change valve stems. So, if you had your's mounted, and the TPS units were removed, then the valve stems will not seat into the wheel. You need new valve stems. Soooooo, If the prior owner kept the TPS system, by removing them from the inner wheel at the valve stem, then that's your problem.

Iceknyght

Nope, the tires are stock on the rims... I bought them from a guy from another local Mustang site and he was getting rid of his stock rims/tires since he had the new ones, so they still had the tires on the rims... He had an '06 as well, so there is/were no TPMS bands on them... That was actually one of the first things the service guy asked is if my TPMS went off... Um, no, the '06 Mustangs did not have the feature yet! LOL!

CooBra07

I asked the tire shop how that hair line crack could have happened...and this is what he told me.

Most tire shops have this machine that does not touch the rim while changing the tire. It works well, your wheel doesn't get scratched. Here is the problem with this new machine. The guy said that these new machines have this hydralic clamp that clamps to the inner part of the wheel to keep it from moving, keep it centered and in place while the tire is being removed or installed. You know what machine I'm talking about ? These machines come calibrated from the manufacture to have a certain amount of clamping pressure. That calibration gets out of whack after normal use. What happens is that they produce more hydralic pressure than what is needed and can damage the wheel...specially the aluminum rims...

Iceknyght

Hmmm... I wonder if something like that could happen from the manufacturing plant? And the weird thing is that while the pressure goes down in the warmer temperatures, it is worse in the cooler temps... That's why I thought it might be a sealing problem somewhere... While I noticed a drop in pressure over the summer months, it hasn't been as dramatic as it has during the winter months... Would aluminum expand and contract in warmer and cooler temps too? I also haven't figured out whether it loses more pressure sitting or after being driven... I lost the 2 lbs. this last time after driving around 200 miles... All things I am trying to consider in trying to figure this out!

CooBra07

Keep us posted...I'm very curious to know what it is. Things That Make You Go HMMMM!!

Iceknyght

Well, as of yesterday, they can't figure out what is going on cause now, the tires don't seem to be leaking air... The weather has been warmer, so I am thinking that might be part of the reason the tires have not lost any pressure... The tires all stayed the same psi from the last time they checked them, so there is not much they can do... We decided that I will bring it in once more next Wednesday and see if there are any changes... If there are, we'll go from there, if not, I may just have them fill the tires with the 'Nitrofill' and see if that doesn't help in the long term...

CooBra07

Good luck with that...Hope you get it resolved...

Quick question - How are you liking your CAI and tune?

Iceknyght

I love it! I am running the 91 race tune from Bamachips and it runs very well! Very nice response and I love that when you get into the higher RPM's, it keeps pulling harder! I had to go back to stock for like a week a few weeks ago for some warranty work and it felt so sluggish compared to what I have with my CAI and tune... As soon as I got the car home that night, I slapped the CAI and tune back in there and I was happy again!

mot250

Unless the cold temps are creating a hard tire that opens up a bad bead seal, I doubt the cold temperatures are the sole cause of the pressure drop because you are not seeing the same pressure drop on all 4 wheels/tires. But, then again, cold temperatures could be exaggerating the problem. Is the air being added in a warm shop while the tires are warm (just driven to the shop) and then are you testing the pressure after the car is outside overnight?

Nitrogen might cure it (or mask the problem further). It does not expand/contract as much through temperature changes as regular compresed air and the molecules are a little bigger so they might not "leak" out as easily.

Good luck!

Iceknyght

I know that when I drop my car off in the morning, they let it set for a while to cool down... I only drive about 3-4 miles from my place to the Ford store, so they don't have a chance to warm up much anyway! They usually stick the car outside, behind one of the buildings, but check the tires in the service bay (and add the air then as well)... Usually around 11am - 12pm or so, cause I usually get a call around noon or 1...

I need to get the car in probably tomorrow for the follow up check-up... Luckily, it doesn't feel like the tires have gone down any in the past week, so that's a good thing (well for my car, not for my sanity)...

CooBra07

Glad to hear that your tire pressure problem might have fixed it's self...

Second quick question:

How did you decide which tune to go with?

Iceknyght

Well, the problem hasn't gone completely away, and I still would love to know why they are leaking in the first place!!

As for my tune, I have 3 tunes with my SCT / JLT combo... I have an 87 Performance, 91 Torque and 91 Race... I have used all three and am using the 91 Race right now and love it! The 87 Perf. tune is nice (and I may go back to it with gas prices soaring!) and the 91 torque was fun, but the 91 race has nice power down low *and* up high... That sucker keeps pulling in the higher rpms and is a lot of fun, especially on freeway on ramps... It's a great 'overall' tune that so far, I haven't found any negatives for... I just read up on here before I ordered my tunes and am glad I did, otherwise I probably would have stuck with the 87 tunes... But the 91 tunes are bit more fun!

Iceknyght

Update:

Took the car in this morning, and the psi on 3 of the 4 tires was in the 20's again (27-28), so they recommended doing the NitroFill and going from there... So I now have Nitrogen in my tires! I will go back in a week to see if this plan works or if we need to try something else... I am kinda hoping this works, cause I am tired of bringing the car into the dealership every week!

smc99007

i had same problem w my fanblades last month... i put half a bottle of fix a flat in and they have been fine since... i think it was my stems...

Iceknyght

I thought about doing the fix a flat thing too, but figured I would take them to the dealership first... Figured it couldn't hurt! If they could figure it out, great! If they couldn't, I was just going to do the fix a flat stuff... We'll see how this goes...