Big Iron

After searching for nearly a year I finally found the 'right' CTS-V, a clean, completely stock two-owner 2005 with 43k on the clock. I'm planning on purchasing a V2 or a C6 in a year or two, so mods will be tasteful and conservative (short shifter, headers, exhaust, tune, etc.).

I generally prefer to baseline new-to-me vehicles to be certain about the maintenance history, and also take care of any recommended preventative maintenance. I've been searching and reading like crazy these past two weeks, but sometimes it's best to start a new thread.

I've read the motor mounts can fail after ~20k miles, and see from the Carfax that one or more was replaced under warranty around 21k. When I turn the car off it shudders a bit, which I've heard is an indication that it might be time again. Keeping a car like this 'tight' is important. I want to make sure it's firm but preserve some semblance of comfort, so no solid mounts for me.

• I've gathered that the motor mount(s) is best done when doing headers?
• Is there a preferred brand of mount (CS over Revshift, etc) for daily drivers?

I also see in the Carfax that the rear differential was serviced at the same 21k service. Unfortunately, the dealership said it was simply a bushing replacement, so it sounds like this has the original differential. Luckily there's only a minimal amount of whine. Being well aware of the V1 Achilles heel, I won't be doing any 6k launches, but I would like to take any economical steps available to prevent/defer issues in the future. I'm much more likely to get on it from a roll than race from light to light. With so many options on the market it's difficult to discern the best route to take here.

• What's the best current option before you get into axles and/or an 8.8?
• Which fluid is recommended for these diffs?
• Speaking of fluids, are there any other fluids that have been found to be better than others in these cars?
• Where's the best place to find a maintenance schedule for these cars?

If you guys have any other suggestions or info I'd appreciate it! I look forward to being part of the V community



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jmilz28

iTrader: (13)

I got mine in December and just finished up what you've outlined. Most of your questions can be answered here, including which particular fluids are spec'd: http://www.cadillacfaq.com/faq/index.html

I prefer Royal Purple, Redline, or Amsoil. I've got all RP in my car now, just because it's readily available in my area. ATF in the trans, 75-90 in the diff, 5w30 oil, dexcool coolant (replace every two years/switch to green or other), synthetic brake and PS fluid. Money no object, Amsoil would be all in. Make sure to flush the injectors, decarb in the intake and top end, these are often neglected but are really helpful. Make sure to flush/change ALL the fluids...including PS, brake, and clutch. I change all the major fluids every two years or 30k. I do air filter, cabin filter, and fuel filter once a year or so. I change my synthetic oil when my oil life system tells me I'm halfway done. Am I overkill on all this? Maybe, but my Suburban has 325k on the engine and still going strong. I added a nice PS cooler, the factory one is rinky dink. The shifter, motor mounts, tranny mount, and diff bushing are all done, I really like the softer CS pieces, feels like factory but will last much longer. I have the CS shifter, but any good one will feel great. Just for age, I'd do plugs and wires when you do the headers, makes it super easy. If you do motor mounts at the same time, that will save you some time and headache. I've done all this, and my car still shudders on shut down. So common, I've learned to live with it. Next up will be sway bars and cradle bushings, followed by headers and a tune, but now we're talking upgrades. If you stay out in front of maintenance and granny shift, these cars are actually quite robust and reliable.

bigti99a

iTrader: (16)

looks like a good find from the crows nest that pic is taken from lol. welcome to the forum. yes motor mounts should be done when doing headers if thats an option. i would say the softer compound is probably what to choose. either brand is fine, CS likely will get you the product faster with great customer service.

as for rear an 8.8 is an undertaking of cost and time for a car that you may or may not be keeping for the long haul. i just drained and put in redline 75-90 fluid in the rear, we also need additive from GM. it seems a little louder but i did a lot of rear end bushing changes at the same time so i doubt its the fluid.

edit... the clutch in these are worth an upgrade when the time comes as well.

crazy tarzan

Decarb intake & top end?

Mercier

iTrader: (15)

+1 for Creative Steel customer service. Second to none.

O'reilley Auto has Royal Purple synthetic for the diff that includes friction modifier. What I used and it was whisper quiet. But I'm going 8.8 now so can't say that experience is with a lot of miles.

Pennzoil makes an actual Synchromesh Manual Transmission Fluid which GM specs for the T56s. This is what I used and I had equally good experience with it. Seems to shift better than the ATF that came out but I honestly don't know how long that ATF was in there. I believe I got this from Pep Boys. Not my favorite place for the people, but you can order online and pic up in store--even pay in store--and they have codes every day for 20%-30% off almost everything on your order. I get a lot of gaskets and hard parts there as well for this reason. If I find something different I want, I step in the corner, order on my phone, use the code, and step right back to the counter and ask them to pull it...with the discount!

WalMart carries the Pennzoil too, I think.

I really need to just reconnect with my local Amsoil dealer and get back on that wagon. IMO, their stuff is always at least a little better than the other guys.

Mercier

iTrader: (15)

I did this using the Seafoam aerosol can with the funky angled injection tube that you slip into your intake tube inside of the throttle body. The kind you run your engine while spraying(need a partner to help) I followed the instructions and just happened to decide to pull the engine for upgrades the next week. Intake ports of the heads that normally get all gunked up from PCV were drastically cleaned. Very impressed. Valves were looking nice too, on a 100K engine.

crazy tarzan

Figured it was a seafoam type treatment, just wanted to verify.

jmilz28

iTrader: (13)

Seafoam is good stuff, so is GM Top End Engine cleaner. Both can be sucked through the intake/TB, through a vacuum line, or actually run the engine off a mix of cleaner and gas. A good service does all three, and you'll be able to tell a difference. If you want a shop to do it, I have had really good results with BG services. When I worked at a Chevy dealer, I saw lots of 5.3s and 6.0s (they were the worst) come in with knocking, especially on cold start. A good decarb fixed about 90% of them and it's good for economy anyway. Due to all the complaints (most of which was due to **** gas and no maintenance) GM eventually started coating pistons, which made this better, meaning you could wait a bit longer to decarb. Avoid the off brand gas, stick to the majors, and you'll extend the intervals at which you need this service. If you regularly put seafoam or similar in your tank, you'll probably prevent the need altogether but once the carbon has built up in the engine/intake tract/injectors it takes a dedicated service to get rid of it.

isis

iTrader: (1)

If headers are on the schedule, do motor mounts first or the same day. If you don't want to do them again, CS will probably last the longest, then Revshift and stock last in order of how long till you replace one. For fluids, any high quality synthetic is good. I use RP too but I'm no shill, it's just easy enough to get and ive always done ok with it. Replacing the diff isn't a requirement if you don't beat the crap out of it every day or race it regularly. I think there's a CTSV faq if you google it. It's not new but neither is the car.

Big Iron

Thanks for the tips guys, especially on the fluids. Good to hear Seafoam works well on these vehicles, I've been a fan of it for a long time. Definitely sounds like CS mounts are the way to go

BudRacing

iTrader: (3)

Replacing the stock differential bushing with a poly unit was the first thing I did. The differential movement and clunking was not tolerable, and the bushing itself was only about 2 years old at the time. It didn't introduce more noise that I recall, but even if there was a little whining or groaning audible under load it was well worth the improved feel.

I used Amsoil 75/90 and their friction modifier in the diff and was happy with the results. I've got about 50k on that fluid now, so I'm due for a change. I think I used Mobil 1 ATF in the diff as that's the best available at the time. No complaints there. Seemed to shift better when I first changed it, and if I recall correctly, I added the half quart of gear oil I had left from my differential. I remember reading that suggestion somewhere on here.

Poly motor mounts won't feel as smooth as a stock set, but unless you don't mind pay for or replacing a stock set every 20-30k they're your best option. I've had the CS motor mounts in for about 4 years now and just added the trans mount in the last few months. I should have done that when I did motor mounts and I would advise you to do the same. It's a pretty easy job, especially when you've got everything out of the way for shifter and/or header install.

If you're looking to reduce wheel-hop and improve the rear suspension feel, I would go straight for the cradle bushings over the axle set. It's a bit more work, and maybe not as high of a priority with your low mileage, but a marked improvement over the stock rubber that allows for a surprising amount of movement even under normal driving conditions.

Sounds like you got a real cherry of an 11 y/o car. Enjoy, and stay ahead of the maintenance curve.

Big Iron

It's needed a few minor things that weren't disclosed (wiper motor cover, trunk struts, etc), but it's definitely a clean car. I still can't believe the mileage when I glance down.

I enjoy maintenance like most people enjoy upgrades (though I enjoy those too!). My FJ80 has a 1/4 million miles on the clock and the dealership couldn't find anything to upsell me.

I'd like to find some hard data on the Amsoil vs Royal Purple.

BudRacing

iTrader: (3)

I remember reading something pretty convincing about Amsoil, but it was years ago. I read a good bit about suggested oils, but most of it was hearsay.

voodoochikin04

iTrader: (3)

Poly driveshaft carrier as well good sir..... =)

BudRacing

iTrader: (3)

Yeah, I wonder what the driveshaft feels like on such a "young" V. I wouldn't know. I've never driven one with less than 90k on it.

jmilz28

iTrader: (13)

CS now has 3 levels of hardness in poly for their motor and tranny mounts. I have the stage 1 (softest) and I'd challenge you to characterize it as anything but stock based on driving it. It's very smooth, I ALMOST wish I'd gone stage 2 but for a DD, it is fantastic. Voodoochikin's driveshaft/carrier service is on my list when my stocker starts acting up.

Over the years, I have delved into this several times, this issue of "best oil." Bobistheoilguy is a great forum. What I've researched, learned from others, and seen myself boils down to, generally: Amsoil 1, Redline 2, Royal Purple 3...with Mobil 1 and Pennzoil Platinum slipping in and out from time to time. This is dependent on the particular product and system usage. I go with RP because it's really good and readily available in my area. I've used M1, Castrol Syntec, Penn Plat, Redline, RP, and Amsoil over the years, all with good results judging from performance, longevity, and looking at the innards of more than one of my engines and others. If I needed 20k+ oil change intervals or was using my vehicle in a life dependent situation, I'd go Amsoil. I use Redline ATF in my 4Runner. Otherwise, I like the balance of performance, price and availability of RP for my purposes. I may eventually start ordering Amsoil, it does seem to be the ultimate best for the most in both auto and moto usages from what I have seen. More important is to actually use a good oil and change it regularly, including gear, trans, etc. Protocol is more important than product. YMMV

Mercier

iTrader: (15)

I was on the phone with Creative Steel just a few minutes ago scheduling the delivery of the rest of the 8.8 stuff and had an interesting conversation with Max. I decided to trade my black bits out for red(harder) and was advised of two things:

1) They only make the transmission mount in black because any harder and he says they got bad vibration there.
2) Red or solid engine mounts I was told are not beneficial in the same way they are in the suspension parts. He said that he almost never recommends the red or solid engine mounts unless the car is 800HP+ and the driver doesn't care about potential of blurry(vibrating) mirrors and the like when a cam or other vibration-inducing mods are present.

I took his advice so I'll have red everything save for black engine and transmission mounts.

YMMV; that's my plan.

FuzzyLog1c

iTrader: (4)

You should never run a harder transmission mount than your engine mounts. When your transmission mount is harder than your engine mounts, the transmission assumes the load that the motor mounts are designed to handle. Consequently, you run a significant risk of breaking the bellhousing (look it up if you're curious--plenty of examples). Max doesn't understand why, but it sounds like he's learned something by trial and error at least.

Royal Purple engine oil is one of the most horrifyingly bad products on the market. Go look up some oil reports or read some of the user reports on the NASIOC forums... it skews in viscosity badly (e.g. going from 5W30 to 5W20 within a few thousand miles). AMSOIL and Redline are your premium options. Mobil 1 if you're cheap. But you'll see double the metals in your oil if you use Mobil 1.

voodoochikin04

iTrader: (3)

We've replaced carriers on 50k and 60k Mike cars.. Due to bad bearings and our turn rubber.

jmilz28

iTrader: (13)

I TOTALLY agree on the motor/tranny mount deal. I prefer the same hardness (like I have now on the V) or even a softer tranny mount, which worked well on my f-body. As far as the oil goes Fuzz, I've done a fair amount of research on this and agree with Amsoil and Redline being best. Can you point me towards some of the reports you're talking about on the RP? I'm always looking for reason to upgrade but would like some details on why. Any help appreciated!