: tire pressure and oil chgs



kehock
05-09-12, 09:12 AM
just swapped my 08 sts-v for a 12 cts-v and am enjoying the new car very much! there was much discussion in the sts-v re tire pressure. the oem specs listed 32psi for both front and back but the general consensus was that 32 front and 30 back was the way to go. what about the cts-v, is 32psi good all the way around? with the new car i get the "free" maintenance for 4yrs (not to be confused with bmw free maintenance) but i'm guessing that the free oil changes will not be on the same frequency that i usually change the oil. i only have 800 miles on the car and i'm wondering what the oil change intervals are.

JFJr
05-09-12, 10:24 AM
I carry 33 psi (cold) front and rear. For street driving it's a good compromise between wear and performance. I change oil about every 5-6,000 miles, even though I could go much longer. Synthetic oil changes are cheap insurance, but all oils get dirty from the by-products of combustion.

Jud

DarkStar76
05-09-12, 10:39 AM
My '12 coupe was delivered with 36psi front and rear... I haven't driven it any other way yet.

TriTexan
05-09-12, 11:19 AM
My new '12 Wagon specs 32 front, 35 rear and that's how the dealer delivered it to me. Realize that the front and rear tires are different sizes and that tire pressure affects the size and shape of the contact patch of the tire. Too much pressure and the contact patch won't be the right size or shape - usually too small and that will compromise grip. Drifters often over-inflate their tires to get better slippage and drift. Too little pressure and the tire will deform under hard cornering and other maneuvers, also compromising the contact patch. Also bear in mind that the front tire's contact patch needs to be different than the rear because it's doing the steering. Front tires are narrower and under the same weight and pressure, this creates a "longer" and "narrower" contact patch, which can improve handling. The rears are wider to provide better grip under acceleration and since those wheels don't pivot their contact needs are different.

All in all, the engineers of the car designed it to work best with the pressures indicated on the door panel. You might have a personal preference for higher or lower pressures. Low pressures might give a little more grip on loose or rough surfaces for example. Higher pressures might give you better road feel or sharper turn-in performance if that's you gig. But if you want a basic recommendation, check the door panel and use those pressures (assuming you are using the stock tire sizes). If you use different tire sizes or brands, then adjustments might be in order.

Cadillac Cust Svc
05-09-12, 11:43 AM
just swapped my 08 sts-v for a 12 cts-v and am enjoying the new car very much! there was much discussion in the sts-v re tire pressure. the oem specs listed 32psi for both front and back but the general consensus was that 32 front and 30 back was the way to go. what about the cts-v, is 32psi good all the way around? with the new car i get the "free" maintenance for 4yrs (not to be confused with bmw free maintenance) but i'm guessing that the free oil changes will not be on the same frequency that i usually change the oil. i only have 800 miles on the car and i'm wondering what the oil change intervals are.
Congratulations on your new CTS-V, kehock! Wishing you many happy miles!

The 2012 CTS-V comes with an Oil Life System (OLS) that calculates when the oil needs to be changed based upon miles driven, engine temperature, and so on. It is possible that given driving conditions the OLS could indicate that an oil change is not needed for a year; it is recommended in the manual to change the oil at least once per year if this is the case and to reset the OLS at this point. While the OLS does calculate the anticipated life of the oil, it does not keep track of the level of the oil in your vehicle, and so it is good to keep an eye on this (checking when you fill up the gas tank). For further information on oil-related maintenance questions, the section pertaining to engine oil begins on page 10-10 in your manual.

All the best,
Sarah
Cadillac Customer Service

TriTexan
05-09-12, 11:53 AM
While the OLS does calculate the anticipated life of the oil, it does not keep track of the level of the oil in your vehicle, and so it is good to keep an eye on this (checking when you fill up the gas tank).

So here's a question - how is it we have the technology to perform advanced calculations that tell us when the oil life is up, but we have yet to be able to simply tell us when the oil level is low? All this technology and a world-class car can't tell you if the oil is low? I know I'm being a little snarky here, but does anyone know why oil level is such a challenge but fuel level is not? I know what while driving the oil is getting splashed around and it's hard to get an accurate reading, but you'd think at rest and once the engine cools, a little sensor could take a quick check and give the driver that info without having to open the hood and pull a dipstick...

Sarah - pass this up to the Caddy engineering team. :xsmile:

pmsteinm
05-09-12, 01:11 PM
I like that the V actually has a dipstick. My wife's BMW doesn't..its electronic. So when that sensor fails (which you know it will) how do you know if the oil level is ok? And after you change the oil, you have to idle for 5+ minutes to get the computer to check the level.

Of course a BMW doesn't need to come with a dipstick because the customer provides that ;)

I do wish there was some sort of clutch wear sensor on manual cars. I hear the hydraulic clutches give almost no warning before they fail. That happened to my wife at VIR, so instead of 5+ sessions, she only got 1 before it went. Would have nice to know before we drove up there it was almost gone.

TriTexan
05-09-12, 01:27 PM
I like that the V actually has a dipstick. My wife's BMW doesn't..its electronic. So when that sensor fails (which you know it will) how do you know if the oil level is ok? And after you change the oil, you have to idle for 5+ minutes to get the computer to check the level.

Of course a BMW doesn't need to come with a dipstick because the customer provides that ;)

I do wish there was some sort of clutch wear sensor on manual cars. I hear the hydraulic clutches give almost no warning before they fail. That happened to my wife at VIR, so instead of 5+ sessions, she only got 1 before it went. Would have nice to know before we drove up there it was almost gone.

Heh! Well just to be clear, I wasn't suggesting that we eliminate the dipstick from under the hood, but that a sensor would be a welcome addition.

kehock
05-09-12, 02:25 PM
i understand the ols and the once per year minimum but my "implied" point was that i have always had the oil changed after fewer miles that the manufacture recommends and i'm asking how many oil changes are covered under the gm maintenance plan? i'm guessing that it's one per year unless the ols indicates otherwise. i'm also guessing that since i'll be having the oil changed every 5-6k that i'll have to discuss with the dealership whether or not the oil change is covered -- each and every time.

----------

the car was delivered with 36 front and rear and i changed that the 32/32 for the same reason you note.

nynd
05-09-12, 02:29 PM
Do you initial changes earlier yourself and don't reset the system. Then, when the system flags you, have GM change it. They will only change when the OLS says to change it or the once a year as mentioned.

Cadillac Cust Svc
05-09-12, 02:47 PM
So here's a question - how is it we have the technology to perform advanced calculations that tell us when the oil life is up, but we have yet to be able to simply tell us when the oil level is low? All this technology and a world-class car can't tell you if the oil is low? I know I'm being a little snarky here, but does anyone know why oil level is such a challenge but fuel level is not? I know what while driving the oil is getting splashed around and it's hard to get an accurate reading, but you'd think at rest and once the engine cools, a little sensor could take a quick check and give the driver that info without having to open the hood and pull a dipstick...

Sarah - pass this up to the Caddy engineering team. :xsmile:

You make a solid point! If I had the resources at my disposal, I'd love to get you more information on why there is no oil level sensor in addition to the Oil Life System; as I don't have these resources, I will document your comments. I wish I could do more than this for you!

All the best,
Sarah (Assisting Katie)
Cadillac Customer Service

GM-4-LIFE
05-09-12, 03:42 PM
I run 32 psi cold for the best ride quality front and rear. I tried running 35 cold, but the ride quality suffered, especially on hotter days. On a hot day, if you start out with 35 or 36 psi cold, it will end up getting over 40 psi and that will cause you to have a very rough ride.

I change my oil when the dealer is willing to do it. I had 2 oil changes done in 10K miles as the dealer was willing to do it while I was in for other services, but most dealers will tell you that they won't do it until you have reached 20% or less on the oil life monitoring system.

M5eater
05-09-12, 04:06 PM
So here's a question - how is it we have the technology to perform advanced calculations that tell us when the oil life is up, but we have yet to be able to simply tell us when the oil level is low? All this technology and a world-class car can't tell you if the oil is low? I know I'm being a little snarky here, but does anyone know why oil level is such a challenge but fuel level is not? I know what while driving the oil is getting splashed around and it's hard to get an accurate reading, but you'd think at rest and once the engine cools, a little sensor could take a quick check and give the driver that info without having to open the hood and pull a dipstick...

Sarah - pass this up to the Caddy engineering team. :xsmile:
The technology exisits. The germans have used it for a while, my 01 S4 had an oil level sensor.

Frankly though, it's something to break. Check the oil once a week, and you don't want a closed system like some cars have and need to rely on a sensor that may fail or takes up to a half hour to calibrate.

it's bad enough the transmissions are sealed.

GM-4-LIFE
05-09-12, 05:25 PM
The CTS-V has an oil level sensor. The message will come on in the DIC, if you are low on oil.

cruiser68
05-09-12, 05:29 PM
My 2011 Silverado 3500 Dually has a low oil sensor that will shut off the engine if it detects low oil. However, I think most if not all diesels have them for insurance. I typically check my oil pretty regularly just out of habit and cause I'm old school....or just old :)

TriTexan
05-09-12, 10:13 PM
The CTS-V has an oil level sensor. The message will come on in the DIC, if you are low on oil.
And you're sure this is oil quantity and not low oil pressure, right?

GM-4-LIFE
05-10-12, 01:57 AM
Yes, I am very sure! I know because I got the low oil level message on my 2010 V. It's there for sure.