djazzmo Posted March 25, 2008 Report Share Posted March 25, 2008 Still trying to find a good used Caddy. I am currently looking at a 1999 SLS with 90K vs a 2000 SLS with 117K. The 1999 is in slightly better condition but I was thinking of going with the higher mileage 2000 because I think that is the year the Northstar started running on regular gas. In my area there is a cost difference of about $.20 a gallon between regular and premium. Also is anyone using mid-grade gas instead of the premium that is reccomended? Does that affect performance or fuel economy? Link to comment Share on other sites More sharing options...
steve6 Posted March 25, 2008 Report Share Posted March 25, 2008 i run 87 octane in my 99 sts. I think 2000 was technically the year the engine was better tuned for 87 octane, Link to comment Share on other sites More sharing options...
MAC Posted March 25, 2008 Report Share Posted March 25, 2008 You can run regular gas with any year Northstar. It says use premium only but the Northstar will still take regular. Link to comment Share on other sites More sharing options...
jking220 Posted March 25, 2008 Report Share Posted March 25, 2008 My 01 STS takes 87... I think its just a knock sensor deal... not exactly sure when it started... trying to find more info online. I would personally go for the 2000... I think 2000 and up was when they fixed the head bolt issues. I dont want to have a chance of head gasket problems... But I drive my N*s hard. Jonah Link to comment Share on other sites More sharing options...
MAC Posted March 25, 2008 Report Share Posted March 25, 2008 Also is anyone using mid-grade gas instead of the premium that is reccomended? Does that affect performance or fuel economy? If you're referring to gas/ethanol, from what I remember, a GM powertrain engineer that use to post here stated that using a mixture of over 10% ethanol is not recommended for engines not designed for ethanol. Link to comment Share on other sites More sharing options...
djazzmo Posted March 25, 2008 Author Report Share Posted March 25, 2008 Also is anyone using mid-grade gas instead of the premium that is reccomended? Does that affect performance or fuel economy? If you're referring to gas/ethanol, from what I remember, a GM powertrain engineer that use to post here stated that using a mixture of over 10% ethanol is not recommended for engines not designed for ethanol. What I was refering to was the 89 octane as mid-grade. It appears from the responses that it is okay to run 87 octane in a pre-2000 northstar but i guess I should be more concerned with the head gasket bolt issues in the pre-2000 engines. Anyone know how common the head gasket and bolt issue occurs? I would think it is in less than 10% of the northstars out there. Link to comment Share on other sites More sharing options...
jking220 Posted March 25, 2008 Report Share Posted March 25, 2008 Anyone know how common the head gasket and bolt issue occurs? I would think it is in less than 10% of the northstars out there. I dont know what percentage people would put on it, but I would consider it far from "uncommon". Jonah Link to comment Share on other sites More sharing options...
fivepointohman Posted March 25, 2008 Report Share Posted March 25, 2008 I have run 87 and 89 with my 96 northstar. Can't see much difference except for at the pump. It's burns less with 87 as obviously a higher octane burns hotter and faster. However I have stayed with 89 since. I am taking my car from NY to SC in april so I will try a tank of 87, then 89 and then 93 to see if and what difference I get on both MPG and performance. Keep you all posted. Link to comment Share on other sites More sharing options...
JimD Posted March 25, 2008 Report Share Posted March 25, 2008 ....It appears from the responses that it is okay to run 87 octane in a pre-2000 northstarThat is correct. The knock sensor technology adjusts ignition timing to prevent piston damage. However, there are fuel economy / performance tradeoffs that make 91 octane the fuel of choice for engines through 1999. It is a separate issue that many / most fuel suppliers force you to choose from 87 or 89 or 94 octane. At least where I live, no one offers 91 octane fuel. ....but i guess I should be more concerned with the head gasket bolt issues in the pre-2000 engines. Anyone know how common the head gasket and bolt issue occurs? I would think it is in less than 10% of the northstars out there.Head gasket "issues" cannot be accurately evaluated by owner's comments on internet sites such as this one. Show me one post from a Northstar owner / driver coming to the internet to ask "why has my engine survived 170,xxx miles with no problems"? People appear on Cadillac boards seeking help with real or perceived problems. Too many owners / drivers are not represented. [sOAP BOX MODE = OFF] Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
djazzmo Posted March 25, 2008 Author Report Share Posted March 25, 2008 ....It appears from the responses that it is okay to run 87 octane in a pre-2000 northstarThat is correct. The knock sensor technology adjusts ignition timing to prevent piston damage. However, there are fuel economy / performance tradeoffs that make 91 octane the fuel of choice for engines through 1999. It is a separate issue that many / most fuel suppliers force you to choose from 87 or 89 or 94 octane. At least where I live, no one offers 91 octane fuel. ....but i guess I should be more concerned with the head gasket bolt issues in the pre-2000 engines. Anyone know how common the head gasket and bolt issue occurs? I would think it is in less than 10% of the northstars out there.Head gasket "issues" cannot be accurately evaluated by owner's comments on internet sites such as this one. Show me one post from a Northstar owner / driver coming to the internet to ask "why has my engine survived 170,xxx miles with no problems"? People appear on Cadillac boards seeking help with real or perceived problems. Too many owners / drivers are not represented. [sOAP BOX MODE = OFF] Okay so the question becomes is the trade off in fuel economy worth the $.20 per gallon I would save by running 87 octane? Also I agree about the head gasket issue. We only tend to hear from the folks that have problems. There is an old saying that says a satisfied customer only tells 1-2 others while an unsatisfied customer will tell 5-10 (or something like that). Anyway I suspect the same principal applies to the head gasket issue. Of course if I had this issue I would complain too because I hear it is expensive as heck. Link to comment Share on other sites More sharing options...
JimD Posted March 25, 2008 Report Share Posted March 25, 2008 Okay so the question becomes is the trade off in fuel economy worth the $.20 per gallon I would save by running 87 octane?That would be a push based on my experience. My spreadsheet shows me there is no consistent-repeatable difference in fuel cost / mile between 87 and 94 octane. The performance part of the calculation is too subjective. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
JohnnyG Posted March 26, 2008 Report Share Posted March 26, 2008 JimD is exactly right here. I've run every kind of gasoline imaginable in my '99 STS. NEVER had a ping or knock (except cold carbon once) and the only difference I can tell is when I put E10 in it. That's 10% ethanol blend, in which case my fuel mileage drops by ...........YEP 10%! That's 2 mpg highway on a car that can get 26 or 27 mpg highway easily on good old conventional (no ethanol) 87 regular of the cheapest variety. BTW, I think I'm going to sell it if you'd like a good well maintained '99 STS with no codes of any importance. All 4 heated seats work, as well as the 6 CD changer in the armrest, the tires are round, the trunk is dry, Oh, and the massaging front seatbacks work too! No sunroof. Diamond White. Looking at an '08 Lux III, Gold mist, w/Tuscany Very Light Linen w/Cocoa Accents. This dealer also has two leftover 2007 STS-V's, said he'd make somebody a great deal! Cars listed for around $77,000, MAJOR HP! Never underestimate the amount of a persons greed. Link to comment Share on other sites More sharing options...
jking220 Posted March 26, 2008 Report Share Posted March 26, 2008 JimD is exactly right here. I've run every kind of gasoline imaginable in my '99 STS. NEVER had a ping or knock (except cold carbon once) and the only difference I can tell is when I put E10 in it. That's 10% ethanol blend, in which case my fuel mileage drops by ...........YEP 10%! That's 2 mpg highway on a car that can get 26 or 27 mpg highway easily on good old conventional (no ethanol) 87 regular of the cheapest variety. BTW, I think I'm going to sell it if you'd like a good well maintained '99 STS with no codes of any importance. All 4 heated seats work, as well as the 6 CD changer in the armrest, the tires are round, the trunk is dry, Oh, and the massaging front seatbacks work too! No sunroof. Diamond White. Looking at an '08 Lux III, Gold mist, w/Tuscany Very Light Linen w/Cocoa Accents. This dealer also has two leftover 2007 STS-V's, said he'd make somebody a great deal! Cars listed for around $77,000, MAJOR HP! what milage/price range for the 99? Im in north-central ohio and I am looking for a good caddy... I really want a moonroof... but I guess I could get over it. Jonah Link to comment Share on other sites More sharing options...
Texas Jim Posted March 26, 2008 Report Share Posted March 26, 2008 I use premium all the time... except for a few times when I accidently put regular in it. I tend to drive fairly spiritedly... so I notice that when using regular, there is a loss of horsepower in "MY" car along with about a 10 % loss of fuel mileage. Reports from others don't seem to have the same problem with loss of mileage. I have read repeatedly that WOT's are good for it... so I try to oblige whenever possible. Love the sound of the Northstar as it goes to 6500 RPM. In my area there is at least a 20 cent difference in price between regular and premium. Most places it is closer to a 30 cent difference. The price is making me think about, is the difference in HP and mileage worth the 20 to 30 cent per gallon extra for premium. So far it is .... TO ME. That may change in the future. ALL the fuel is this area is 10% ethanol. When traveling In other areas ... WITHOUT the 10% ethanol .... the car runs noticeably better and gets better mileage. But as I travel around over the country, more and more areas are using the 10% crap. I hate it. Link to comment Share on other sites More sharing options...
Texas Jim Posted March 26, 2008 Report Share Posted March 26, 2008 Looking at an '08 Lux III, Gold mist, w/Tuscany Very Light Linen w/Cocoa Accents. This dealer also has two leftover 2007 STS-V's, said he'd make somebody a great deal! Cars listed for around $77,000, MAJOR HP! JohnnyG, Sounds like a beautiful automobile. Gold Mist with Light Linen Tuscany. About the STS-V... If I remember right... FOUR HUNDRED AND SIXTY NINE HP. I looked at one before I bought the second DTS Performance sedan. That thing was very FAST. The only thing I didn't like, it seemed to be smaller and a little more confining then the DTS. Thats about the only reason I didn't buy it. I was looking for the biggest thing I could find. It was a hard decision as I really like HP. The more the better. Link to comment Share on other sites More sharing options...
JohnnyG Posted March 27, 2008 Report Share Posted March 27, 2008 Yes Jim, I thought it would be a very nice car too. I took my wife down to the local dealer to look at the color today, it took her about 2 seconds to nix that one. She likes the Diamond White, like our STS. I found one with Shale Tuscany w/cocoa so that will be my next choice. It doesn't sound too bad, just a little too much like the one I have now. I'd prefer the Light Linen at least. I'm not going to consider the STS either, I'm like you, a little too cozy inside and the high beltline is a little too confining for me. I like to be able to see all around when I'm driving, not look over a door sill. what milage/price range for the 99? Im in north-central ohio and I am looking for a good caddy... I really want a moonroof... but I guess I could get over it. Do me a favor and look one up on Kelly Blue Book.com or one of those sites. I'll allow for the lack of moonroof, but I don't think you find a better maintained STS anywhere. About the only thing I haven't done is change the wires and plugs, but at 93,481 miles, it is just due for that. New battery last year, Michelins have about 2 years of tread left, interior has one little mark on the armrest lid. Just PM me with an offer if your interested. A trip to Marietta OH is fun anytime, I'll meet you. Never underestimate the amount of a persons greed. Link to comment Share on other sites More sharing options...
JohnnyG Posted March 27, 2008 Report Share Posted March 27, 2008 Oh yeah, and the gauges do the "sweep sweep" needle thing, something I'm CERTAIN I'm going to miss! Never underestimate the amount of a persons greed. Link to comment Share on other sites More sharing options...
Texas Jim Posted March 27, 2008 Report Share Posted March 27, 2008 Oh yeah, and the gauges do the "sweep sweep" needle thing, something I'm CERTAIN I'm going to miss! JohnnyG, My DTS does the "sweep sweep, needle thing." I would ASSUME the 2008 does also. Link to comment Share on other sites More sharing options...
JohnnyG Posted March 27, 2008 Report Share Posted March 27, 2008 Thanks Jim! I know it shouldn't be a big deal, but somehow it is. I thought that feature was gone based on one of our discussions a few months ago. I'm so relieved! Never underestimate the amount of a persons greed. Link to comment Share on other sites More sharing options...
KHE Posted March 27, 2008 Report Share Posted March 27, 2008 I have run 87 and 89 with my 96 northstar. Can't see much difference except for at the pump. It's burns less with 87 as obviously a higher octane burns hotter and faster. However I have stayed with 89 since. I am taking my car from NY to SC in april so I will try a tank of 87, then 89 and then 93 to see if and what difference I get on both MPG and performance. Keep you all posted. The fuel burns at the same rate - the octain rating indicates it's ability to resist knocking. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
Texas Jim Posted March 28, 2008 Report Share Posted March 28, 2008 Thanks Jim! I know it shouldn't be a big deal, but somehow it is. I thought that feature was gone based on one of our discussions a few months ago. I'm so relieved! Here is a pic of mine. Link to comment Share on other sites More sharing options...
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