Automobile Enthusiasts

Kali

(55,740 posts) Mon Feb 23, 2015, 11:46 AM Feb 2015

fancy modern car/tire question

how do those automatic tire pressure warning things work? I have a very slow leak - maybe a lb or two every 3 or 4 days. it causes a warning light to come on and that drives me nuts. now even though the car CAME with some goo and a compressor INSTEAD of a spare (not even a donut) the manual warns that it may cause problem with the little sending unit.

now, having lived on dirt roads with plenty of cactus I have used foam for more or less permanent repairs for decades.

is it going to ruin something if I just put a can of foam in there? I am betting the tire repair guys are not even going to be able to find this thing (and with my luck it is probably in the sidewall anyway) it is that slow.

4 replies

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fancy modern car/tire question (Original Post) Kali Feb 2015 OP

It depends on the make/model of car. benEzra Mar 2015 #1

I think it is the direct type Kali Mar 2015 #2

Don't use the goo! sir pball Mar 2015 #3

You might be able to find it yourself Major Nikon Mar 2015 #4

benEzra

(12,148 posts)

1. It depends on the make/model of car.

Reply to Kali (Original post)

Sun Mar 1, 2015, 08:42 PM

Mar 2015

My car-before-this-one used the antilock braking sensors to count tire revolutions, and if one tire started consistently increasing its rotation rate (which meant the tire was losing diameter, hence had to spin faster) it would give a low pressure warning. Some newer cars may use actual pressure sensors in the wheel and transmit to the CAN bus via a low power radio interface, but I'm not positive.

Aha, an article:

https://en.wikipedia.org/wiki/Tire-pressure_monitoring_system

What kind of car/truck?

Kali

(55,740 posts)

2. I think it is the direct type

Reply to benEzra (Reply #1)

Sun Mar 1, 2015, 09:10 PM

Mar 2015

since the manual says if you use the goo, it may cause issues with the thing.

Kia Soul

sir pball

(4,941 posts)

3. Don't use the goo!

Reply to Kali (Reply #2)

Wed Mar 4, 2015, 06:51 PM

Mar 2015

Souls use valve stem sensors, run the goo through them and you're out $60 on top of the tire repair.

Haven't the foggiest idea why the car would come with the too, except to inflate (no pun intended) your repair bills…

Major Nikon

(36,900 posts)

4. You might be able to find it yourself

Reply to Kali (Original post)

Tue Mar 31, 2015, 01:46 AM

Mar 2015

Put a few drops of dish soap in a spray bottle and fill it up with water. Spray the tire down and look for bubbles.

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