Heads up: tow vehicle valve stems

[P. Raz]

This past fall I replaced my tires on our 2009 Frontier. At that time the tire place "serviced" the TPMS valve stems which included new valve caps. Before leaving on our spring trip, I went to check my tire pressure only to find one cap unremovable. A small wrench helped me remove the cap but unfortunately cracked the valve stem which turns out is made of aluminum. A trip to the Nissan dealer and $175 to replace the TPMS unit fixed the problem. Because of the road salt used here in the winter, coupled with the fact that the replacement valve caps were chromed steel, corrosion occurred over the winter. The service manager told me this was common and to expect to replace the other three units within the next couple of years due to either corrosion or battery failure. A heads up- if your stems are aluminum, plastic caps and a little grease might extend the life. Raz

[Dick & Joanne]

My Nissan service manager told me that plastic caps cannot be used with TPMS. He did not say why.

Dick

[gmw photos]

My '06 Frontier came with aluminum caps on aluminum stems.

The problems usually arise from using steel caps on the aluminum stems, because galvanic corrosion occurs between the dissimilar metals.

For 'anti-seize' ( but mostly to just make it easier to get the caps off, and to make sure the threads don't strip ) I use a drop of Boeshield T-9. This is a liquid product that was developed by Boeing to be safe to use on metals such as aluminum, stainless, etc.

I suspect the reason some service managers say to not use plastic caps is because there are a lot of cheap plastic caps out there that do not have a gasket in them, so they don't seal well. If you shop around, you can find 'good' plastic caps with the little gasket in them. Original equipment Honda motorcycle caps are made well, and I'm sure there are others.

[P. Raz]

Originally Posted by Dick & Joanne

My Nissan service manager told me that plastic caps cannot be used with TPMS. He did not say why.

Dick

Interesting, when the dealer replaced the TPMS unit it came with a plastic cap and they replaced the other 3 with plastic as well. I bet George is correct about the seal.

[floyd]

Schrader valve mounted TPMS's have proven to be the wrong approach.
They are commonly destroyed when demounting tires. The stems are exposed to the elements and can not be serviced separately. A bad two cent core could result in spending hundreds of dollars for replacement.
This is something to be considered when choosing a new tow vehicle...
Some companies,such as Ford, use an internal rim mounted TPMS. It is out of harm's way to a tire tech with a minute's training, and they allow for changing stems when purchasing new tires. They can also be moved to virtually any aftermarket rim.
They still don't allow for battery change and like the schrader mounts, must be replaced as a unit.
Remember these things and their costs are mandated on cars after 2007... pushing a few more people out of the market for a new car.

[gmw photos]

Originally Posted by floyd

Schrader valve mounted TPMS's have proven to be the wrong approach.
They are commonly destroyed when demounting tires. The stems are exposed to the elements and can not be serviced separately. A bad two cent core could result in spending hundreds of dollars for replacement.
This is something to be considered when choosing a new tow vehicle...
Some companies,such as Ford, use an internal rim mounted TPMS. It is out of harm's way to a tire tech with a minute's training, and they allow for changing stems when purchasing new tires. They can also be moved to virtually any aftermarket rim.
They still don't allow for battery change and like the schrader mounts, must be replaced as a unit.
Remember these things and their costs are mandated on cars after 2007... pushing a few more people out of the market for a new car.

Hi Floyd,
I agree that these can and often are damaged by careless installers, which will be an expensive mistake.

However, you can buy "rebuild kits" for them for a few bucks each, such as this one:

TPMS Rebuild Kits

[Carol H]

Originally Posted by Dick & Joanne

My Nissan service manager told me that plastic caps cannot be used with TPMS. He did not say why.

Dick

It depends on the vehicle make and year.

In 07 a number of manufactures started using rubber stems & plastic caps on cars equipped with TPMS systems - my Subaru is one of them.

here is link that explains it.

[Borden]

Our car has the pressure sensor stems but turquoise blue octagon shaped (I think plastic valve caps) to signify nitrogen in the tire?

[Tim Wood]

Raz, I ran into a similar problem with our 09 Subaru Forester on the corrosion from salt. By the way what engine do you have in your Frontier and is it 2 or 4 wheel drive ?

[P. Raz]

Four liter V6 and 4wd. Are you planning on towing the Parkliner with the Forester?

[Tim Wood]

Raz, No I have a 3.8 Kia Sedona Van that I will be pulling the new trailer with. I just happened to look at a 2008 4x2 Nissan Frontier 4.0 and was wondering what can I expect on gas milage ? Its also an auto. If you like you can pm me any info likes or dislikes etc. too I would really appreciate it.

[idiotsniff]

Raz,

you could have bought a whole set off ebay for about $100 dollars or one for about $30

our 09 corolla has the plastic caps with seals in them.

if you insist on the steel caps, try never seize, it works well.

I live in canada and have no issues with corrosion on these TPM sensors

[841K9]

My 1 ton Chevrolet has the metal valves.
They're slowly failing one by one.
Luckily, 10,000lbs and up are emissions exempt.

[DMAC1]

actually not required in canada but most cars come with them as most car companys just put them on for the "north american" market.