Blog Post: Cadillac XLR – oh we barely knew ye

[Bruce Nunnally]

In 2004 Cadillac introduced the Cadillac XLR (Experimental Luxury Roadster).  Featuring an enhanced Corvette chassis and the Cadillac Northstar Engine, the new XLR was the very first car available with the magnetic MR suspension.  I covered the XLR in detail here, but I love these images of the final, 2009 XLR;And what a luxurious interior:It [...]

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[Jan Olsson]

This is just about the only roadster I can think of that is really beautiful!

The XLR, the old SRX, the new and old CTS and the STS have IT.

Sorry to say that the new SRX looks like a Toyota in my opinion.

The XTS is really nice inside, looks great! But the outside, well I guess it takes time to appreciate the exterior, just as it was for me when they first introduced the "art and science" theme. I remember that I thought that the rwd STS looked hideous..

I still think that the upper level Cadillac should have its own unique platform and its own unique engine choices though.

[CarlaValentine]

What exactly is Magnetic Ride Control suspension? I've seen this term on the boards a couple times and I tried to google it but I haven't found anything that explains what it is/how it works. From what I have read it's a good suspension system, but what sets it apart from, say, automatic level control suspension?

[Jan Olsson]

What exactly is Magnetic Ride Control suspension? I've seen this term on the boards a couple times and I tried to google it but I haven't found anything that explains what it is/how it works. From what I have read it's a good suspension system, but what sets it apart from, say, automatic level control suspension?

Cadillacs have had various forms of SSS (speed sensing suspension) and RSS (road sensing suspension) since the early 90's. The firmness of the shocks is varied in different ways. Earlier systems had a valve basically letting the dampers have 3 different levels of firmness, later systems has a proportional type valve letting the dampers adjust variously (CVRSS = continuously variable road sensing suspension) and starting late 2002 with the STS the MRC (magnetic ride control) was introduced. Audi and Lamborghini are allowed to use them too.

The big difference with MRC is that there are no valves or other moving parts involved to set the dampener stiffness. It is achieved "simply" by changing the viscosity of the damping fluid by having electromagnets "charge" the fluid. The result is the fastest reacting suspension system in the world, about 10 times faster reaction than any other dampener system. Different cars allow different setups. For instance the rwd STS gives the driver 2 different general setting to choose from (softer/firmer).

Automatic level control has nothing to do with the suspension more than the fact that it controls the level of the rear end of the car to keep the level.

[CarlaValentine]

What exactly is Magnetic Ride Control suspension? I've seen this term on the boards a couple times and I tried to google it but I haven't found anything that explains what it is/how it works. From what I have read it's a good suspension system, but what sets it apart from, say, automatic level control suspension?

Cadillacs have had various forms of SSS (speed sensing suspension) and RSS (road sensing suspension) since the early 90's. The firmness of the shocks is varied in different ways. Earlier systems had a valve basically letting the dampers have 3 different levels of firmness, later systems has a proportional type valve letting the dampers adjust variously (CVRSS = continuously variable road sensing suspension) and starting late 2002 with the STS the MRC (magnetic ride control) was introduced. Audi and Lamborghini are allowed to use them too.

The big difference with MRC is that there are no valves or other moving parts involved to set the dampener stiffness. It is achieved "simply" by changing the viscosity of the damping fluid by having electromagnets "charge" the fluid. The result is the fastest reacting suspension system in the world, about 10 times faster reaction than any other dampener system. Different cars allow different setups. For instance the rwd STS gives the driver 2 different general setting to choose from (softer/firmer).

Automatic level control has nothing to do with the suspension more than the fact that it controls the level of the rear end of the car to keep the level.

I see. Thanks. CVRSS is what I meant to say, but the term escaped me and auto level control was the only other thing I could think of. I figured someone would know what I was talking about.

[JimD]

The abbreviations can get in the way. I suspect the dealer network balked at having to pronounce the technical term . Magneto-Rheological is the technology applied to struts and shocks that have a MR suspension system.

http://www.lord.com/Home/MagnetoRheologicalMRFluid/MRFluidTechnology/WhatisMR/tabid/3772/Default.aspx

[Jan Olsson]

The abbreviations can get in the way. I suspect the dealer network balked at having to pronounce the technical term . Magneto-Rheological is the technology applied to struts and shocks that have a MR suspension system.

http://www.lord.com/Home/MagnetoRheologicalMRFluid/MRFluidTechnology/WhatisMR/tabid/3772/Default.aspx

It would be nice to visit the dealer and tell them something like "It seems like my CVRSS and possibly the PAL don't work right on my STS. Could you please check the FPR and MAF too, or maybe it's just the IAT?

I'm happy if they get me the right oil filter without arguing

[JimD]

....I'm happy if they get me the right oil filter without arguing

The last time (three plus years ago) I drove up to the service entrance at a Cadillac dealer I was looking for a simple oil change by a person who had at least seen a Northstar powertrain once or twice. I told the service writer that I wanted exactly 7 quarts of 10W-30 oil plus a filter installed and do not touch anything else anywhere else on the vehicle.

He replied that a 20 point system check was what they did and they only stocked 5W-30 oils. I suggested he open the door quickly before I drove through it.

[Texas Jim]

My car has the Magnetic Ride.

It is great.

I really like it.

Here is another explanation of how the Magnetorheological fluid works.

http://en.wikipedia.org/wiki/Magnetorheological_fluid

QUOTE from another article..

A magnetorheological fluid is a fascinating smart fluid with the ability to switch back and forth from a liquid to a near-solid under the influence of a magnetic field.

The term "magnetorheological fluid" comes from a combination of magneto, meaning magnetic, and rheo, the prefix for the study of deformation of matter under applied stress.

Magnetorheological fluids are not currently in wide use but are considered a futuristic type of material.

END QUOTE

[Jan Olsson]

A word of caution. Magnaride does very mean things to your driving habits. Expect flashing lights and extended fingers...

[Jan Olsson]

That's one of the main reasons I do the service on my own. I have only had 2 visits at service departments since 1992... The guys at the SAAB-dealer ower here where I used to buy parts run away when they see me

I can't think of one single time without some kind of argument with the morons. The last part I bought was just an oil filter. When I discovered that they had raised the price with 50% since the last year (which still was 30% more expensive than the year before that) I told the poor employee that he was nuts..well Rock-Auto will get my money in the future for ALL parts, not just expensive ones.

I have always used the recommended fluids. I wish I had a dime for every comment like "whats so special about your car that it can't use this 10W-40 oil?", "well this oil is for modern cars, not american cars", "this is a good oil, everyone buys it" etc etc

[Texas Jim]

A word of caution. Magnaride does very mean things to your driving habits. Expect flashing lights and extended fingers...

Been there....Done that.

(laughing)

[CarlaValentine]

That's one of the main reasons I do the service on my own. I have only had 2 visits at service departments since 1992... The guys at the SAAB-dealer ower here where I used to buy parts run away when they see me

I can't think of one single time without some kind of argument with the morons. The last part I bought was just an oil filter. When I discovered that they had raised the price with 50% since the last year (which still was 30% more expensive than the year before that) I told the poor employee that he was nuts..well Rock-Auto will get my money in the future for ALL parts, not just expensive ones.

I have always used the recommended fluids. I wish I had a dime for every comment like "whats so special about your car that it can't use this 10W-40 oil?", "well this oil is for modern cars, not american cars", "this is a good oil, everyone buys it" etc etc

My owner's manual states 10w30 for my car and my climate...yet I still had the guy at the parts store trying to convince me that I should get the 10w40 synthetic for high mileage. I don't understand why these people have to argue. These are our vehicles, not theirs, and therefore it's pretty safe to say that we know them better than they do. Obviously you don't have to have much knowledge about cars/trucks to work behind a parts counter...

[JimD]

....Obviously you don't have to have much knowledge about cars/trucks to work behind a parts counter...

I really should be silent on this "knowledge" point, BUT!

Your comment "might" apply to automobile dealer service writers, dealer technicians, dealer parts counter employees, aftermarket parts counter employees, quick oil change franchise owners/employees, and and on (the list is endless). The customer/consumer has limited access to the qualifications of any of those people. And what level/standard of qualification would put your mind at ease?

Give that some thought and then expand the question to things like medical services.

Are you nervous yet?

[CarlaValentine]

....Obviously you don't have to have much knowledge about cars/trucks to work behind a parts counter...

I really should be silent on this "knowledge" point, BUT!

Your comment "might" apply to automobile dealer service writers, dealer technicians, dealer parts counter employees, aftermarket parts counter employees, quick oil change franchise owners/employees, and and on (the list is endless). The customer/consumer has limited access to the qualifications of any of those people. And what level/standard of qualification would put your mind at ease?

Give that some thought and then expand the question to things like medical services.

Are you nervous yet?

It wouldn't take a certain level or standard of qualification to put my mind at ease. It would simply take finding someone who doesn't try to belittle me and who doesn't act like just because he/she is the one behind the counter that they know more about my car than I do.

[Jan Olsson]

It wouldn't take a certain level or standard of qualification to put my mind at ease. It would simply take finding someone who doesn't try to belittle me and who doesn't act like just because he/she is the one behind the counter that they know more about my car than I do.

Exactly!

[Jan Olsson]

Regarding the advices one gets from the service departments. Many times it's just a matter for them to sell whatever they store and while their products won't harm anything in a short term basis or even on a long term basis for many users, they are still wrong.

Other times they truly believe that they know what they are talking about but they are still wrong.

The only facts that I rely on are what the user’s manual, service manual and people like our former guru says. I've always followed these rules:

1) Use what's recommended. If I use something that's not OEM I generally use these parts where other systems won't be harmed by me not using OEM.

For instance, I would never use an aftermarket oil filter because the engine might be hurt, but I can consider using AC-Delco parts even if they aren't the OEM for that specific part when buying brake pads, shocks, mufflers etc.

2) Read up and listen to the guys who were involved in the design and testing rather than a shady tree "mechanic" telling you that this and that always worked on his cars. I believe that experience is great but it should be seen as a complement to the engineer’s advices rather than THE truth.

About oil...Carla, your car was specified with standard of the shelf 10W-30 oil, nothing fancy. Your manual also states that you should be looking for the ILSAC starburst symbol, meaning that the oil is the latest developed oil for gasoline engines. This doesn't apply to an older than 2002 or so Cadillac with the Northstar engine.

GM uses API (American Petroleum Institute) standards and one API class has conventionally "outperformed" the superseded class. SM is better than SL etc.

But API looks into how oil performs in today’s engines, which means that a SM oil not necessarily is better for your engine than a SG oil for instance.

This wasn't a problem until the early 2000's when the oil industry decided to reduce the amount of ZDDP (Zincdialkyldithiophosphate) in engine oils.

The ZDDP was used to lubricate surfaces subjected to high contact pressures (distributor gears, oil pump, camshaft/lifter surfaces). Today’s engines are constructed in such way that the ZDDP levels can be held low. Today’s oils contain just about 10% or less ZDDP compared to an early 1990's oil.

The solution is to use a 10W-30 oil with an older API class if available (SH). You can also use a "high mileage oil" since they contain higher levels of ZDDP or an oil suitable for BOTH gasoline and diesel engines.

The guru also told me that a 15W-40 oil would be fine if there was a problem finding a 10W-30 oil over here. The mileage and cold start ability could be hurt though.

Below is the original answer:

Your english is fine. Better than my German or whatever.....LOL

You are correct in assuming that the later API grades such as SL or SM are "better" and , as such, supercede the earlier grades. That is conventional wisdom and is pretty much the case as one of the API requirements is that "improved" performance grades supercede prior grades and are always backwards compatible.

Having said that.....the current crop of oils "rated for gasoline engines" that are on the shelf in the most obvious locations in the stores are also "fuel economy" oils. Any oil with the ILSAC "starburst" symbol that says "for gasoline engines" is a bit of a hybrid....those oils meet the latest API performance specs, have the minimum allowable ZDP (to prevent catalyst contamination) and have friction modifiers in the oil for fuel economy improvement.

The difference is that the API specs just relate to the oil's performance as tested on gasoline engines. API specs have nothing to do with friction modifiers or MINIMUM ZDP levels. The API specs just have minimum performance specifications based on actual engine testing.

Understand that the API performance specs have a lot of requirements besides just "wear protection". Most all of the improvement in the latest grades is in the area of temperature protection. The latest oils will still perform at hotter and hotter engine temperatures. So they are "better" in that the older oils might start to oxidize and give up around 290 degrees F and the latest oils will still function well at 310 or 315 degrees F. They are not "better" in that they give more wear protection.....they just have better high temperature resistence, among other things.

More modern, current production engines are designed to run with the minimum ZDP oils and friction modified oils. Clearances are changed, designs are changed to add roller followers everywhere that are not ZDP dependent for preventing wear, wear surfaces are hardened where necessary, etc.....

Older engines designed for the SF and SG oils that had more ZDP in them are not as well protected against ZDP depleted oils.

So...technically the older engines should be OK with the new SM oils since the SM oils "technically" supercede the older oils and are backwards compatible. But the newer oils probably are " barely" adequate in terms of anti-wear additives such as ZDP. If the engine is perfect inside it will likely be fine. But if the engine is marginal for wear the ZDP depleted oil MIGHT cause a problem and accelerate wear. Certainly you would not want to use the newer ZDP reduced oils for long change intervals in the older engines.

An older 93 Northstar, for instance, has 32 rubbing element tappets (flat tappets) that require much more ZDP for protection against wear than the 2000 and later Northstars with roller tappets.

If you want to be sure your engine has the best wear protection you can do two things. One, use one of the non-"gasoline engine" oils such as the diesel Rotella or Delvac or Delo oils. Those oils have much more anti-wear protection since they are also certified for diesel use. The other thing you can do is to spike the oil you are using with extra ZDP by adding a pint or quart of GM EOS (General Motors

Engine Oil Supplement). The EOS is available at any GM parts counter and is sold as an assembly lube. It is basically plain motor oil

with a high concentration of ZDP that will fortify any crankcase fill with the extra ZDP desired for more anti-wear protection. It is the only oil "additive" I would ever recommend as it is specifically designed for this purpose.

If you look at the container of Rotella/Delvac/Delo oil you will see in the fine print that it meets all the API diesel performance specs (combinations of the letters CC and CD, etc.) AND it meets the latest gasoline API performance specs such as SL or SM. Now look at the ILSAC "for gasoline engine" oil across the isle in the autoparts store. Read the fine print. It meets the API gasoline SM specs but does NOT meet any of the diesel performance specs. The diesel specific oil is a much "better" product in terms of wear protection if your engine needs it. Diesels have a much greater need for anti-wear protection due to the soot and combustion byproduct contamination of the oil due to the high compression and high cylinder pressures of the diesel engine, so the oils for diesels have to be much better.

I would recommend the Rotella/Delvac/Delo oils for the 93-99 Northstars, personally. The latest ILSAC fuel economy oils are getting very low in ZDP concentration. Fine with the newest engines on the road but not so fine for a 93 Northstar.

You can get the Rotella/Delvac/Delo oils in 10W30 for your engine but they are much harder to find. Check a truck stop or large equipment supplier. If all you can find is the 15W40 version of the Rotella/Delvac/Delo that is fine in the 93 Northstar. The oil is not that much thicker to hurt anything unless you live in the far north and need to cold start at -40.

The other option is to use one of the "severe service" oils marketed by Mobil that are designed for longer change intervals and marketed as such. If you read those bottles you will notice that they also do NOT meet the ILSAC "for gasoline engine" use as they do not have the ILSAC starburst symbol. That is because those oils designed specifically for longer change intervals also have more ZDP in them that excedes the amount allowed for the ILSAC starburst designation.

I would recommend the conventional diesel Rotella/Delvac/Delo oils. I personally use the Delvac (Mobil) in most everything around the house.

[CarlaValentine]

Not to sound like an idiot here or anything, but what do SM and SL mean?

[Jan Olsson]

Not to sound like an idiot here or anything, but what do SM and SL mean?

It's the API service grade. Gasoline engine oil use the prefix S followed by a "generation" letter. SM oil supersedes the SL oil which superseded SJ (K were excluded).

Well it seems like I've hijacked the thread. Sorry for that Bruce!