Those of you in cold weather climates...TPMS sensors..

[QuassEE]

We've been hitting 20 degrees F almost daily for the last week, and I'm having some quirky weirdness going on with the TPMS sensors in my car. I need advice from those of you who live in colder climates.. When your TPMS sensors go off due to cold weather (less air in the tires) do you bother filling them or just leave them? We initially put 2psi in to go from 30 to 32 on 33psi recommended tires, which will likely put us up at 34 when the weather is a bit better.. I have PAX so the recommendation is actually to go 1psi over, but the cold weather recommendation is 1psi under for additional grip.

Questions...

Is it normal for TPMS sensors to go off at these temperatures?
What do you do, ignore it or put some additional air in? What is the rationale for this decision, based on driving on ice/snow?


I live in Vancouver, so we NEVER EVER EVER get this type of weather, let alone in December (our cold months are January and February).. We very rarely have a white Christmas--maybe a handful of times through my life. It's actually so cold that people are opting to not leave the house.. This is my first winter with TPMS sensors, since my previous van (Sienna) didn't have them.

Oh and my doors and hatch are freezing shut (been using lukewarm water) on my van and my SUV won't even start 1/2 the time if it has been sitting in the cold.. We don't plug our cars in here, it's unheard of, but what advantage does that have?! I know it's something you cold weather people do.. We also don't have remote starts on our cars here, again--because we just don't get this type of weather..so I thought.

Hey, it's not the usual "coat or no coat" question ;)

-Nicole.

[Pixels]

20 F is cold? I don't even put a coat on for quick trips at 20.

Yeah, you should add air. Tires naturally lose air over time anyway, so in a month they probably won't need to be bled if the temp goes back up.

Your doors are freezing because you are putting water on them. At this point there might not be anything to do but put more water on, but next time, try not to. Ice over the outside of the car, break off. If you have all the visible ice off and you can't get the door open, try the others. If you can get one open, someone should go inside and push the other door open while you are pulling from the outside.

There is no reason your SUV shouldn't be starting at 20F. That's really not all that cold. I'd say something is wrong with it, that it wouldn't be starting even if it was warmer.

Engine heaters are used on diesels to help keep the fluids flowing. My dad has one on his F350 diesel, but he doesn't have to use it all the time. He likes to use it cuz he can. I've never heard of anyone plugging in their gasoline cars in the contiguous US. Maybe if there is someone on here from AK they can chime in. :D

[QuassEE]

The doors freeze shut here because we go above freezing at random, or the sun comes out, and melts enough of the snow to freeze over once the sun is gone or the temperature goes back down.

I know 20 doesn't seem cold to people who live in cold climates, but it's really quite cold here, because we don't have a dry cold and we live 2 minutes from the ocean which means a lot of water and wind. It's a completely different type of cold here--we often have liquids from things warming up for a bit... Lots of black ice, and our cars are NOT routinely winterized... I've never had problems with a vehicle not starting in cold water (starts great on warm days) and so I bought a new battery for it and will see if that solves the problem with the SUV.

I'm a bit iffy on putting air into the tires, though. The sensor warning goes off once I've been driving for a bit.

-Nicole.

[New grandma]

If the doors freeze shut, try pounding with your fist along the edge. My son lived in N. Dakota for a while with no garage and he had a heater that plugged in at night for his car and it worked very well. Here in MN. many apt. buildings provide plugs for cars that are left outside. I haven't personally tried it because we garage our cars.

[bubbaray]

You might want to check the connectors on your SUV battery and even replace it if it is older -- a soon to die battery can be more problematic in cold weather.

I have an Ody and have taken it to various ski hills in the Coastal region (ie., colder temps than we are currently having) and never had the doors or hatch freeze shut on me. I have an '05 Ody. I am not having that problem with my Ody in our current temps here. I did have one washer fluid nozzle freeze up a couple of days ago, but it thawed in the sun later in the day.

I don't have the RF tires, thankfully. I know quite a few people who have them on various vehicles and not a single person likes them, especially when they have to replace them at $1200 a tire!

[bubbaray]

I've never heard of anyone plugging in their gasoline cars in the contiguous US. Maybe if there is someone on here from AK they can chime in. :D

Block heaters aren't just for diesels -- and IIRC, the heaters on diesels (glow or globe lamps?) are something different (they don't need to be plugged in). Block heaters are what get plugged in. VERY common in northern Canada, the Prairies, Yukon, Alaska, NWT, etc. I would suspect that people in the Midwest like North Dakota would have to use them too. They keep the engine block warm so that it d/n freeze and crack. I know people in Alberta and even colder areas who have not one but two block heaters.

Those are the cars that have a foot of extension cord sticking out of the front grill. Not terribly common here in the Lower Mainland, usually seen on the cars with the out of province plates.

ETA: photo & better explanation of block heaters here: http://en.wikipedia.org/wiki/Block_heater

[beeman]

First lets cover tires.

A tire will normally loose pressure as the temperature as the temperature drops do to 'shrinkage' of the air. Bump them up to the proper pressure again. Once the nice weather hits in again check your pressure again, as you will likely have to bleed some off :twocents: . Having the tires inflated properly will give you the best control on ice and snow. Being under pressure likely won't give better traction, but will decrease control of the vehicle. TMPS sensors are sensitive, so being set off due to the drop in temperature is very likely, however ice and snow buildup can cause improper readings in snowy climates. The sensor will shut off after the tires warm up from driving, however the recommended tire pressure is to be taken cold. That should take care of your tires.

Plugging in the block heater has definite advantages in cold climates. It keeps the oil slightly warmer than outside temperature so that it is less viscous, and it warms the moving parts of the engine so that they are closer to operating temperature when starting, leading to easier starting and less stress on the engine. I usually plug my gas truck in below -15 to -20 C, however, it will start (begrudgingly) below that. At -6 C it is not necessary IMO.

Older batteries start misbehaving below freezing, especially if they've been frozen without a charge. That may be a culprit of problems on your SUV.

Keep the warm water away if at all possible. That just ads more ice that sadly won't melt away until a nice sunny day. See if you can get some lock de-icer. If that fails, the hair drier always works well and removes moisture rather than add it ;) . If there is any, heated underground parking is your best friend for thawing your vehicle out, however this can lead condensation building in the fuel tank, so gas line antifreeze will be necessary to keep optimal performance.

Once the warm weather sets in again make sure to give your vehicles a thorough washing, especially the underside, to get rid of all salts that have been used for de-icing the roads. Salt is the leading cause of premature vehicle corrosion.

Happy winter driving, and have fun winterizing!

[An Aurora]

Sorry to go OT, but we have gas cars and have block heaters on all of them. I plug my van in while I am at work, although lately I haven't really been needing it (it was 10* above today when I got to my car at 7:30 pm). Here if you park outside you really need an oil pan heater, but you can get by without a block (engine) heater. Fairbanks needs block heaters.

ETA: we had a remote start on a car here in AK, and then moved to AZ and it was fantabulous! We could actually get in our car without baking.

[snowbird25ca]

Every single vehicle I've owned has had a block heater. In fact they come standard on any new vehicle you buy here - you pay for them, but they're already on the vehicle. When the weather is -30, they're needed on any vehicle whether it's gas or diesel. ;)

Our TPMS came on a week ago when it first got so cold, and we'd had about a 15 degree celcius drop in just a few days. (was -22 F) Our tires had to lose almost 20% air pressure before the sensor came on though. (And yes, they were properly inflated before winter hit.)

I pretty much agree with everything Beeman said. :thumbsup:

[QuassEE]

I suspect I'll be parking in the garage until this weather stops...

I just drove from Vancouver to Seattle and back in a snowstorm because SeaTac shut down and I had to pick someone up. My wiper fluid nozzles were frozen the whole time (I thought my mirror heater worked on them, but I guess not..) and I was literally driving an interstate highway with almost a full foot of snow scratching along the underbelly of my car for miles on end.

I decided to go with 1psi in each of the tires, going to 31. The reason for this is because we can alternate to a warm day easily--it doesn't usually stay cold here for more than a day or two...I should be up at 34 cold soon. Brrr.

This is the first time I've really felt the cold since moving back from California...not liking it.

-N.

[shauburg]

I had to laugh at this thread because the TPMS on DH's vehicle has been driving him nuts ever since the temperatures really dropped here just over a week ago. He's seriously thinking of buying an air compressor to keep in the garage so he can easily make the adjustments needed to keep the thing from going off every few days. Not to mention that all of the gas stations around here either seem to have out-of-order/non-existant air stations or they charge you $0.50 for a few minutes of air!

Seriously though, I think his TPMS must be malfunctioning. I drove the same vehicle last year when it dropped to -40°C and don't remember it ever going off. DH comes home complaining about it every few days!

Yes, DH does put air in when it goes off (and checks the pressure manually, not just relying on the TPMS reading). Rationale being that the air contracts when it cools, so you really do have to add more air to get the required psi.

ETA: Also note that getting your tires filled with nitrogen will help. It's less prone (though not 100% immune) to contraction in the cold.

[snowbird25ca]

ETA: Also note that getting your tires filled with nitrogen will help. It's less prone (though not 100% immune) to contraction in the cold.

Excellent point. I'd forgotten about nitrogen - apparently tires last longer when you fill with nitrogen too and I think I've even heard you can get better mileage? I think you have to pay to have it done though?

[QuassEE]

Places are just starting to do it here... :) I'm not sure how much it costs, though.

[southpawboston]

ETA: Also note that getting your tires filled with nitrogen will help. It's less prone (though not 100% immune) to contraction in the cold.

right. nitrogen is more immune to changing pressure with temperature than air.

Excellent point. I'd forgotten about nitrogen - apparently tires last longer when you fill with nitrogen too and I think I've even heard you can get better mileage? I think you have to pay to have it done though?

i haven't heard about tires lasting longer, but the other advantage to nitrogen is that it does not diffuse through rubber as quickly as air. yes, tires lose air normally to the air "leaking" out of the rubber through microscopic pores. so, your tires hold their pressure longer assuming no other breaches to the tire such as a slow leak puncture.

nitrogen does cost (it can be a huge profit maker for a tire shop, charging as much as $10 per tire for $0.10 worth of nitrogen gas), and many people debate whether it's worth the cost. for example, if your tire does have a slow leak, and you have to keep adding nitrogen every few weeks, that could turn into a ridiculous waste of money.

personally i haven't tried nitrogen. if i could get my tires filled with it for cheap, i may consider it to try it out.

[CPSDarren]

right. nitrogen is more immune to changing pressure with temperature than air.


This baffles me. Both dry air and dry nitrogen behave as ideal gasses at these temperatures and pressures, don't they? They should follow the exact same law for pressure vs. temperature, especially given that air is mostly nitrogen anyway.

Now if you used compressed air vs. dry nitrogen from a tank, I could see that a significant amount of moisture in the tire could be a factor as the water vapor turns to liquid or solid.

I've also heard that over time, nitrogen filled tires may not lose as much pressure since the oxygen is absorbed by or leeches through the rubber more readily.

[TechnoGranola]

That's -6°C? I am coming to visit you!! Today, when I woke up this morning it was -39°C/-38.2°F and that is WITHOUT windchill. :p The weather here sucks!

And (as already said), the reason your pressure sensors aren't warning you after you drive for awhile is because the tires have warmed up and the pressure has increased. Recommended tire pressure is for cold tires, so ensure your tires have the recommended pressure in them at standing temps (not being driven). When your air temp goes up again, you'll need to let some air out.

Do your TPMS just have a warning? or do they also tell you current tire pressure? Ours actually report the pressure, so it's kind of cool to watch how it changes as the tires warm up.

Oh, and here's a good quote from CanadianDriver http://www.canadiandriver.com/articles/jk/tire-inflation.htm

Always check tire pressures when the tires are cool. Air expands when heated and even driving a kilometre will warm the air in the tire and increase pressures. For every 10°C change in air temperature, a tire's inflation pressure will change by about 1 pound per square inch (PSI). An under-inflated tire heats up quickly, so the pressure may show correct if it has been driven, but the tire is actually operating too hot and could fail.

[TechnoGranola]

A few articles I found on nitrogen in tires (not sure if they're valid, but they're interesting!):

Is it better to fill your tires with nitrogen instead of air? (http://www.straightdope.com/columns/read/2694/is-it-better-to-fill-your-tires-with-nitrogen-instead-of-air)
Nitrogen Filled Tires: a Scam? (http://ahotcupofjoe.wordpress.com/2008/07/05/nitrogen-filled-tires-a-scam/)
Nitrogen beats air in tires (http://www.canada.com/calgaryherald/cars/story.html?id=c9300414-e397-48b3-8f6f-2b0410cdb66b)

[southpawboston]

This baffles me. Both dry air and dry nitrogen behave as ideal gasses at these temperatures and pressures, don't they? They should follow the exact same law for pressure vs. temperature, especially given that air is mostly nitrogen anyway.

Now if you used compressed air vs. dry nitrogen from a tank, I could see that a significant amount of moisture in the tire could be a factor as the water vapor turns to liquid or solid.


yeah, i'm confused by this as well. i suppose it could be the moisture component in the air that accounts for the change in pressure, but that would seem like you would need a large amount of water in the air for it to contribute to such a large changes in pressure.