TPMS light, once, but pressures fine?

Yeah, on Amazon, this exact model of external TPMS is sold under several brand name from $30 to $80 for a set. Mine is from Favoto and it was $40. I suspect they are manufactured from the same place. One thing you might want to be careful is that if your tires see salt on the road in winter, you may want to take off the external sensor once in a while and lubricate the thread with WD40 or something suitable. It does have a tendency to seize on to the valve stem. If it does, the only way to take it off is to destroy the sensor or the valve or both. It happened to my son's car with exactly the same TPMS sensors.

 

My understanding is that WD40 is not suitable for applications where you want some oil or grease to stay in place as a lubricant or moisture seal. It all evaporates.

Pick something else that doesn't completely evaporate in a short time.

 

I used this on mine. Suppose to protects metal from rust and corrosion for up to 1 year outdoors. WD-40® Specialist® Long-Term Corrosion Inhibitor 6.5 oz. | WD-40 So far over full NE winter, it did not seize.

 

Good thought. A couple of cars back I had what I thought was a slow leak - lost 5 psi, then didn't again, then started again. Turned out to be a good valve cap with a seal - stopped the slight valve leak, but not all my valve caps were "seal" type.

Maybe if you put cheap valve caps on for a few days (or months) and see whether you've got a valve leak?

 

I.e. not the regular multi-use stuff.

 

Yeah, I did not use "regular" muti purpose WD40, but for this application, even "regular" muti purpose WD40 may work OK if you do re-apply frequently enough, like once a month. It does penetrate the metal and prevents corrosion while displacing water. As long as there is frequent enough separation of two metal surfece (TPMS sensor cap thread and valve stem metal thread) they should not seize.

 

WD-40 and similar products do leave a residue. Back in the '70s, I had a friend who was an Auto Electrician. Back then MINIs (and other cars) had ignition problems in wet weather, and the standard "fix" was to spray with WD-40, CRC or RP7.

My friend loved it - because it meant that after a few applications, and build-up of dust in-between, left a coating on plug-leads, dizzy cap etc. The more it was sprayed on, the shorter it would last before needing another application.

Which led to work for him either cleaning them up or, often cheaper, selling a new set of leads.

 

On our *other* car the TPMS stem corroded and the tire lost pressue suddenly (got a flat) at high speed on the higwhay.
Had to be a day late on a trip to make TMPS repairs.

@fuzzy1 Yes TPMS reacts fast to light up if there is a low pressure value in the data register. What I am talking about is when the system thinks the tires are OK, but the TPMS is dead so it is not sending new data. That very first time the TPMS light comes on, it takes the Gen2 system a while (20-30 minute ride) to populate the register with a "NA" reading. Once the data register has "NA", the light will come on right away for the future trips. If the TPMS somehow was internittent failing, then once in a while it would go through this whole cycle again.

Another way to say this, on a Gen2 we can temporarily turn off the TPMS light by giving the system bogus TPMS codes for the tires. If you do not hit the RESET, it takes the system about a 20-30 min or so ride to determine all the readings are NA. If the owner only ever does short trips, this can keep the TPMS light off for a month or longer. In other words, low pressure reading is quickly flagged. But if there is no reading, it takes the system a while to figure that out. However, once the system figures it out, the light will stay on until a good reading, or until codes are reset manually.

 

I used it all the time as an AA patrol in the late 70s and 80s to dispel moisture (condensation etc.) inside distributor caps and on ignition coil necks in wet weather in the rainy UK.

 

Yes, I used it all the time, early-mid '70s - I lived in an area where there was often constant drizzle for days or weeks in a row - but when I realised that the dust it attracted and made a coating which, when damp, conducted electricity, I stopped using it. Actually after spending time cleaning it off, I think with degreaser.

 

OK, so it use to be a good product, but not so much now? What do you use now in 21st century? I just picked up a can of WD-40 "Specialist" Silicone lubricant @The Professor mentioned. WD-40® Specialist® Water Resistant Silicone Lubricant 11 oz. | WD-40 But it seems this product does not displace water like the original multi-purpose WD40 does.

 

Probably not - this is primarily a lubricant, and is designed to leave a residue. For a valve cap, probably both would be fine.

With a '69 Corolla, you can use WD-40 liberally - and when it cakes up with muck, dose it in a few lots of degreaser, wash it down the drain like we used to in the '70s. But today - washing it off on the side of the road would be frowned on. Plus - hosing off a modern engine, no way.