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The tire tech who replaced my tires told me not to use metal valve caps since they can ruin the sensor.

For you 2003 AE people what type of caps came with your magnesium rims?

The only info I can find is about the nickel core and aluminum caps.

Anyone know anything about this?

I found the following info
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http://www.hunter.com/pub/undercar/TECHLINK/index.htm

1TIP: Do not replace either the cap or the valve with standard parts. This will interfere with the sensor’s ability to transmit.

TIP: The TPM sensor is more precise than consumer-grade tire pressure gauges. It may be necessary to explain this if the customer routinely mis-inflates tires using a gas station gauge.

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from our forum

2-27-2005, 07:24 PM #61
MAJ Z06
Moderator
St. Jude Donor '05-'06

Member Since: Oct 2001
Location: One round, one down. Ft. Knox, KY

How to add tire pressure sensors.

Tire Pressure Monitoring System Information Addition
A tire pressure monitor (TPM) system is used on Cadillac DeVille, Seville and Chevrolet Corvette. This system was discussed in the November 2000 TechLink. This is a brief review, because there is some new service information available.

Sensors
The sensor, with built-in valve stem, is inserted from the inside of the wheel, through a hole in the rim. It is retained by a nut (4 N.m, 35 lb. in.) and is sealed by a grommet. A lithium battery with a design life of 10 years powers the sensor.

Each sensor is coded differently. This permits the receiver to determine exactly which tire is over or under-inflated.

The sensors are mounted within the well of the rim. It’s important to be careful when using a tire-mounting machine. The sensor could be damaged in two ways: either by (1) direct contact with the machinery or (2) by the bead of the tire as it is forced over the rim.
Sensor ruined by tire mounting equipment

The valve stem cap is made of aluminum and the valve core is nickel-plated to resist corrosion. The end of the stem serves as the sensor’s antenna.

TIP: Do not replace either the cap or the valve with standard parts. This will interfere with the sensor’s ability to transmit.

TIP: The TPM sensor is more precise than consumer-grade tire pressure gauges. It may be necessary to explain this if the customer routinely mis-inflates tires using a gas station gauge.

OUR97

I have read all that before and there may be some reason that standard valve caps can't be used. Poor transmission of sensor signal is the usual bs they give. I have replaced mine (Previous Owner lost all 4) with the cheap chrome ones from NAPA and the sensors work fine. So that makes me believe that whoever writes that stuff (GM lawyers) are trying to cover their own a...
If you aren't supposed to use any aftermarket caps, then why do they sell the fancy ones in the catalogs? (Besides to get your $ that is)
I say do what you want and enjoy.

Evil-Twin

All I can say is WOW... if the stem serves as the antenna .. what is the antenna designed into the circuit board for??? all those people who removed the stem to band them into their custom wheels are in deep trouble then huh???

MTurnbo

The stems themselves ARE NOT the antenna. I cut mine off (no... the stems!) and they still work just fine.

Evil-Twin

I was being sarcastic in my post I know it isn't me but I was just trying it out to see if I could possibly be sarcastic

Cart99

I had a tire tech tell me the same thing about the metal caps -- something about a corrosion problem. But I thought it sounded like

EscapePod

I also got the same BS from the 17 year old tire mounter at Discount Tire. The problem was, when I put the aluminum caps (from the factory) back on, the sensor problems continued. I have replaced one rear sensor (nowhere near 10 years of service --- more BS!), and now the other rear seems to be crapping out.

A re-train with a good sized magnet is usually good for 3 - 6 months.

In fact..... I think I'll put the fancy chrome caps back on.

C5Vette168

I got some from Pep Boys. I haven't noticed any problems either.

Vetteman Jack

Sounds like to me. I've been running chrome caps on mine for years and the sensors work just fine.

Dark-Knight

Another urban myth!

RPOZ4Z

I've noticed you getting more sarcastic in your old age!

I changed the factory plastic valve stem caps with metal ones, never had a problem with the sensor working properly, and it's been about 4 years.

mschamberger

The effort is appreciated ET. The sarcasm was so out of character for you that I assumed your account had been hi-jacked.