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Car Forum / Nissan / Nissan Cars / October 2007All 4 tires losing pressure in 2007 Altima
They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all down to 29-30. I only noticed it because the Tire Pressure Monitoring System light came on. Is this possibly a problem with the TPMS causing a slow leak? cold weather can cause it (air shrinks as it gets colder, expands as it gets hotter) > They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all > down to 29-30. I only noticed it because the Tire Pressure Monitoring > System light came on. Is this possibly a problem with the TPMS > causing a slow leak? > cold weather can cause it (air shrinks as it gets colder, expands as it gets > hotter) [quoted text clipped - 3 lines] >>System light came on. Is this possibly a problem with the TPMS >>causing a slow leak? Have you had all 4 tires replaced recently? My guess is that the technicians who replaced them weren't knowledgeable about the high tech valve stems as menitoned in another post, so all your replaced valve stems are busted. CD >> cold weather can cause it (air shrinks as it gets colder, expands as >> it gets hotter) [quoted text clipped - 10 lines] > > CD maybe a batch of bad rims?  SignatureJim Yanik jyanik at kua.net > They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all > down to 29-30. I only noticed it because the Tire Pressure Monitoring > System light came on. Is this possibly a problem with the TPMS > causing a slow leak? Did you make sure to measure the tires at the same outside temps and conditions? Fact is that a nice cold tire in the morning just before you start off to work may read 32 PSI, but when you stop at the gas station off the highway after driving 65 mph, that same tire will read 36 PSI. The best time to read your tire pressure accuratley is when the tire is cold. CD > > They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all > > down to 29-30. I only noticed it because the Tire Pressure Monitoring [quoted text clipped - 11 lines] > > CD I have measured them cold, and they had definitely lost pressure. Also, there was a guy behind me waiting for the air pump at the gas station who also had a new (month old) '07 Altima, and he was having the same problem with all 4 tires losing pressure > > > They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all > > > down to 29-30. I only noticed it because the Tire Pressure Monitoring [quoted text clipped - 17 lines] > station who also had a new (month old) '07 Altima, and he was having > the same problem with all 4 tires losing pressure WIFI at the gas station? Awesome!:) Must the the tire pressure monitors, then. CD Its very doubtful that it is the TPMS. The odds of having all 4 TPM tire pressure valves leaking the same amount of air over the same period of time is beyond the realm of probability, unless Nissan has a bunch of defective valves out there. I assume that you know never to check tire pressures when the tires are hot or have been driven on. I would suggest that it is the weather, when cold or hot, the pressure can change as much as 5 PSI. Your best bet would be to set the pressure when the car has sat overnight and then check them a week later to see if there has been any change. Pressures should be taken with an digital tire pressure gauge, the barrel types are generally not accurate. I set the Tire pressure on my two 07 Altimas at 33 PSI, cold, sitting overnight. > They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all > down to 29-30. I only noticed it because the Tire Pressure Monitoring > System light came on. Is this possibly a problem with the TPMS > causing a slow leak? TPMS transmitters are likely banded to the rim inside the tire. There would be no way the TPMS system could cause pressure loss. DS TPMS transmitters (sensors) on Nissan and Infiniti are integrated into the valve assembly. There is a rubber o-ring which seals the transmitters to the rim and held in place by a screw on spacer (nut). When you remove the valve assembly the o-ring has to be replaced. The Banded kind of TPMS is generally used in Ford Products Truck and SUV . Stewart wrote: > They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all > down to 29-30. I only noticed it because the Tire Pressure Monitoring > System light came on. Is this possibly a problem with the TPMS > causing a slow leak? TPMS transmitters are likely banded to the rim inside the tire. There would be no way the TPMS system could cause pressure loss. DS > They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all > down to 29-30. I only noticed it because the Tire Pressure Monitoring > System light came on. Is this possibly a problem with the TPMS > causing a slow leak? As noted in other posts-----you could easily see a 5-6 psi change in tire pressure (either way) depending on when you initially measure it. Chances of an even leak on all 4 tires is not likely. A bit of arithmetic will bear this out. At a constant Volume---P1/T1=P2/T2 So P2=P1*T2/T1 Starting out with a tire pressure =30 psi and Temp =10F (or 470R) If the tire temp goes up to 110F (or 570R) Then the new pressure =30*570/470=36.4 psi MLD > They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all > down to 29-30. I only noticed it because the Tire Pressure Monitoring > System light came on. Is this possibly a problem with the TPMS > causing a slow leak? 1. After being mounted and inflated, new tires stretch, I suppose over a period of days. 2. The beads may not seal completely at first. 3. A film of dirt or corrosion on the rim or tire bead may prevent a complete seal. (I have a tire that stayed up a month, then went down overnight because the bead on one side wasn't cleaned before it was mounted. I'm trying to clean it out without removing the tire.) 4. Humidity in air pumped into tires can cause a pressure change between one "cold" temperature and another. 5. Air permeates through the rubber of tires, and some rubbers may lose more than others. For example, five pounds a month is in my experience typical for natural-rubber tubes. > > They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all > > down to 29-30. I only noticed it because the Tire Pressure Monitoring [quoted text clipped - 17 lines] > more than others. For example, five pounds a month is in my experience > typical for natural-rubber tubes. Thanks - the new tire issues you mention make the most sense for what happened >>> They all lose pressure evenly. Started at 35 psi 4 weeks ago, now all >>> down to 29-30. I only noticed it because the Tire Pressure Monitoring [quoted text clipped - 19 lines] > Thanks - the new tire issues you mention make the most sense for what > happened You can see I've always had trouble keeping my pressure up. A first-rate mounting job would include cleaning the tire bead and polishing the corresponding part of the rim. The last time I had a tire mounted it was for a spare. The mechanic told me, I'd better run on it a few days because that would help the bead seal. >>>> They all lose pressure evenly. Started at 35 psi 4 weeks ago, now >>>> all down to 29-30. I only noticed it because the Tire Pressure [quoted text clipped - 27 lines] > told me, I'd better run on it a few days because that would help the > bead seal. I believe cast aluminum("alloy" wheels have to be sealed (on the inside),as the alloy is porous;perhaps Nissan has a bad batch of wheels,maybe they missed the seal coat? That would explain why all 4 wheels are leaking,and that others also have the same problem. SignatureJim Yanik jyanik at kua.net |
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