New Truck Questions

marpel · November 29, 2011

Awaiting the arrival of a factory-order truck (2012 Sierra 1500 w 6.2) and have a couple questions:

The dealer advises that they now sell all new vehicles with nitrogen in the tires because the molecules are larger than air and, as a result, the tires don't leak over time like air-filled tires. Didn't think of it at the time, so didn't ask - Does this mean the tire (barring puncture etc) will not lose pressure at all or it just takes longer to deflate? And, if it does deflate and requires filling, are there pumps out there to put nitrogen in the tire? Is this nitrogen thing just marketing hype or is it the real deal??

I've read a couple comments about the best mileage to do the first oil change and it appears opinions vary. I presume the idea is to drive the vehicle long enough to "loosen" all the metal filings but not too long so they potentially remain in the oil and "scar" the engine? Is there a best mileage for this first change?

Along the same lines, I will likely have to tow my travel trailer from B.C. to Denver within a month or so of delivery. As a result, the tow may closely follow the break in period. Is it recommended to have a longer break in period, if intending to tow, or is the recommended mileage the same regardless? Logic suggests the mileage should be the same as many of these trucks are purchased/leased for business tow purposes so you'd think the recommended mileage would take that into account, however, thought I would check, nonetheless.

Thanks in advance

Marv

MaverickZ71 · December 1, 2011

Congrats on the pending arrival of your new truck! I'm jealous of your 6.2L engine.

The nitrogen-in-the-tires thing is up to you. Dealers around here charge around $50 to let all the air out of your tires and refill with nitrogen out of a big bottle and change your valve stem caps to the green ones. Nitrogen provides a more constant PSI reading than regular air; the tires don't lose or gain as many PSI when cold or hot when filled with nitrogen. But if you've got a bad wheel or a bad tire, nitrogen will still leak out. Myself, I figure the General puts in good old regular air at the factory, and I haven't had any problem with leaking wheels, so I'm running regular atmospheric air in my tires.

The General doesn't tell you to do a special oil change for your engine break-in period, but a lot of folks on this forum will do the first oil and filter change at 500 or 1000 miles (regular, not synthetic oil), with the thought that it will remove any metal shavings from your oil. The brand new trucks come factory filled with Dexos synthetic oil, so you may want to extend that first oil change interval out a little to 2000-3000 miles or so, if you choose to do so.

My '09 Silverado owner's manual specified a 500 mile break-in period with no towing during that period. I'd say that whatever your break-in period is, after that, it's ready for normal service, including towing, but if it were my truck, I'd tend to take it a little easier on the brakes and tranny and not hammer them during towing at first.

Enjoy your new truck

Stevens03 · December 1, 2011

Congrats on the new truck.

I prefer 1000 miles before the first oil change and run synthetics from that point forward. I've never had an issue in all the years.

I also believe 500 miles is the break-in period before towing.

joshw1303 · December 1, 2011

I changed my first oil change at 7500km and refilled with dexous. In that first 7500km I did not hammer the gas or tow or anything. Just easy drives to let the truck brake in nice and easy. Now that i did my first oil change few months back now. Shes ready for play.

yamahas · December 1, 2011

The dealer put Nitrogen in my new truck. I had nitrogen in my old 2500 and never had any leak out the stem or anything.

Often if you buy tires from say Costco you can go back there and get a nitrogen fill up if you ever need it at no charge. At last that was what they told me, never needed a top off from summer to winter or ever once I put the Nitrogen in.

Pumper · December 1, 2011

OK this Nitrogen thing drives me insane. When I was working at a service station in High School (5 years ago) I always got asked about Nitrogen in customer's tires.

I would like to point out that air at see level is approximately 80% Nitrogen already. The additional 20% is the essentially made up of CO2 and O2 and Ar with a few other trace elements and contaminants.

Running ~100% Nitrogen does only one thing, it makes the tire less susceptible to temperature changes. In a normal tire, you will see that as you drive the tires warm and the air in the tire expands causing a increase in tire pressure. Nitrogen however does not react as violently to small temperature changes. This means that common driving will not result in temperature fluctuations. Even from summer to winter the pressure change will be much less drastic than atmospheric air.

The part that bothers me is that people that hold jobs where people trust and listen to them (dealerships) tell people that the molecules are larger and that this prevents leaks. The size of a molecule is unimaginably small and makes no difference when a tire has a slight leak. By these peoples logic if you had a leak then all of the "non-Nitrogen" components of the air in your tires would leak out and then you would have all Nitrogen in your tires any way and they would never go flat they would only lose 20% of there overall volume since atmospheric air is 80% Nitrogen.

jdubub · December 1, 2011

OK this Nitrogen thing drives me insane. When I was working at a service station in High School (5 years ago) I always got asked about Nitrogen in customer's tires.

I would like to point out that air at see level is approximately 80% Nitrogen already. The additional 20% is the essentially made up of CO2 and O2 and Ar with a few other trace elements and contaminants.

Running ~100% Nitrogen does only one thing, it makes the tire less susceptible to temperature changes. In a normal tire, you will see that as you drive the tires warm and the air in the tire expands causing a increase in tire pressure. Nitrogen however does not react as violently to small temperature changes. This means that common driving will not result in temperature fluctuations. Even from summer to winter the pressure change will be much less drastic than atmospheric air.

The part that bothers me is that people that hold jobs where people trust and listen to them (dealerships) tell people that the molecules are larger and that this prevents leaks. The size of a molecule is unimaginably small and makes no difference when a tire has a slight leak. By these peoples logic if you had a leak then all of the "non-Nitrogen" components of the air in your tires would leak out and then you would have all Nitrogen in your tires any way and they would never go flat they would only lose 20% of there overall volume since atmospheric air is 80% Nitrogen.

me likey

Dale_K · December 2, 2011

I'm pretty sure that any gas expands expands & contracts at the same rate in response to temperature. Here's a link.

http://en.wikipedia.org/wiki/Boyle's_law

As stated earlier, the everyday air around you is already 80% nitrogen. The only justification is moisture reduction and I suspect that the car assembly plants probably have dryers on their tire inflation compressor systems.

Personally I will never pay extra for nitrogen filled tires. I'll walk out first.

Pumper · December 2, 2011

I'm pretty sure that any gas expands expands & contracts at the same rate in response to temperature. Here's a link.

http://en.wikipedia.org/wiki/Boyle's_law

As stated earlier, the everyday air around you is already 80% nitrogen. The only justification is moisture reduction and I suspect that the car assembly plants probably have dryers on their tire inflation compressor systems.

Personally I will never pay extra for nitrogen filled tires. I'll walk out first.

I did work with a guy that used nitrogen in his racecar so that he could better predict tire pressure in extreme condition

MikeNH · December 2, 2011

There are two main users of N2 in tires. Race cars, where a fraction of a PSI can mean the difference between holding a corner and eating the wall, or airplanes, where a tire goes from the subzero temp of cruising altitude to well over 100 degrees at touchdown. Unless you plan on running the truck in the Daytona 500 or figure out how to turn it into an airliner, N2 in tires will do absolutely nothing. If the service is free then whatever, but paying extra for that would be stupid.

Likarok · December 2, 2011

I have also noticed in both of my new trucks that GM has installed synthetic oil from the factory. First new truck I have ever seen that.

marpel · December 3, 2011

Thanks for all the replies (and the congrats on the soon-to-be new truck. Currently have a 4.8L Sierra, so the 6.2L will be a big change, especially when pulling the trailer!!).

I like the more stable temp fluctuation aspect of Nitrogen, but doubt if I will go out of my way and/or pay to get Nitrogen in future tire fill-ups. I neither plan on racing this thing nor driving it off a cliff to see if it can fly!!!

As a result of comments, I will likely do the first change at around 1000, and replace with full synthetic. For the little effort and moderate cost, may as well start off right.

I will definitely be able to get a 500 mile break-in period but, the way things are looking, not much more than that before I tow to Denver. I'll just take it easy on the way down (I drive pretty easy anyway, especially when towing). The upside is the trailer is only around 4000 lbs, fully loaded, so it shouldn't tax the engine too much (which is why I opted for the 6.2).

Thanks again.

Marv

waumo1 · December 3, 2011

Nitrogen will not hurt anything but it does not really provide any benefit either except to the people selling it. N2 actually has a larger gas constant than dry air meaning it expands and contracts more with temperature than dry air. Key word being "dry".