Cadillac CTS 4 AWD driveline care and feeding

Messages
532
Location
Houston, Texas
Hey everyone, newbe member here. I just purchased a 2012 Cadillac CTS 4 with a 3.6 liter V6 and all wheel drive. The car has 60k miles with no service record so I intend to replace every lubricant in the car. I intend to keep it indefinitely and my driving habits are a bit more spirited than the average Cadillac owner. These are my questions: The owners manual calls for 5W-30 semi-synthetic. I searched for common issues with this engine and found the timing chains tend to stretch causing various trouble codes to light up and the only fix is to tear it down and replace the chains and tensioners. I live in South Texas where the heat averages 100 deg F in the summer. Should I go with a higher viscosity such as 10W-30 or 10W-40 to provide more shock load cushioning on the chain rollers and preserve idle oil pressure? The owners manual states to stick with the recommended weights (of course it always says that but IMO the engineers aren't concerned with the vehicle past the warranty expiration). Should I flush it before the change? Transmission: Dexron VI I've ordered 6 bottles of Transtar ATF. Their website indicates this company manufactures GM labeled fluids. https://www.walmart.com/ip/ATF-Flui...-LV-SP-IV-SPH-IV-WS-FZ-ZF6-ZF8/126963350 Front and read differentials: 75W-90 with 4 oz of limited slip additive. Ordered Mobile1 LS 75W-90 and no additive. Transfer Case: This is my biggest question. Owner manual indicates Transfer Case Fluid GM PN 88861800 I called Mobile's customer support number, was transferred to a higher level of support, and the agent stated they list no fluid for this application. I found a topic on this board with a similar year and model vehicle and the final answer was either straight ATF or motorcycle engine oil as gear lube kills the carbon fiber clutch plates. If that suggestion holds am leaning towards a full synthetic H-D spec oil or just going with the factory fluid. I want to make sure the internals last. I have bottles of Lucas Transmission Fix and Lucas Oil Stabilizer on hand. Should I use these or leave them out? Thanks in advance. I've had success in the past keeping older vehicles running by going with my intuition and past experience as a service tech on vintage imports and dealership vehicles but this is the most complex vehicle I've tinkered with.
 
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520
Location
South Wales, UK
What are the lowest temperatures you are likely to start the car up from cold in? (Does that sentence even make any sense? LOL) Now I'm not familiar with this engine, we don't have it over here in the UK but I'm assuming chain driven and port injected? Oils that are shown to give the least wear are those with thicker base stocks. If you're a hard driver and you enjoy changing your own oil then maybe synthetic isn't the way to go. You're likely to have the same or even better results using a quality mineral monograde such as Supertech HD30 or a a multigrade with a thicker base stock such as a 15w40 or 15w30 (can you still get Delo400 15w30??). That said, something like Castrol Edge 0w40 A3/B4 should do you well too!
 

IMSA_Racing_Fan

Thread starter
Messages
532
Location
Houston, Texas
Hey thanks for the reply. It never drops below -10 C here. An old timer mechanic that I apprenticed under would say "those runny oils are used to achieve MPG targets for the EPA, always go with one weight higher"
 
Messages
520
Location
South Wales, UK
Originally Posted by IMSA_Racing_Fan
Hey thanks for the reply. It never drops below -10 C here. An old timer mechanic that I apprenticed under would say "those runny oils are used to achieve MPG targets for the EPA, always go with one weight higher"
You'd be stretching it with a monograde 30 at -10°c, however a 15w** would work well. There's also synthetic 15w40's out there such as Rotella T6 or boutique options from the likes of Amsoil or Redline. I personally enjoy running cheaper oils and changing them more frequently. However, it's all down to an individuals taste. Regardless, this car will give up due to something that isn't an engine oil related failure, so don't think too hard about it. Like I said before, you could use Castrol 0w40 A3/B4 for 10k intervals without a sweat!
 
Messages
1,718
Location
SW Ontario Canada
Ignore the oil life monitor and change the oil at least 2x per year with a top quality synthetic and you won't have much to worry about. If it is possible, a inexpensive amazon boroscope camera inspection into the valve covers will give you an idea if past maintenance issues caused sludge buildup
 
Messages
8,859
Location
Texas
Do not up the viscosity of your engine oil expecting "better protection." Use a better quality oil and change on schedule. Modern engines with variable cam timing may throw slow cam phaser response codes with the wrong grade oil, among other things like slower pump-up of lash adjusters and cam chain tensioner on cold starts... which if you're looking to crutch up a sketchy timing chain design is the OPPOSITE of a good thing. As for the Lucas additives... I wouldn't use a Lucas branded product to start a fire, let alone in anything I cared about. No pour-in engine oil additives. EVER.
 
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Messages
8,501
Location
Texas
2008 CTS 3.6DI owner here. Timing chains are covered for 10yrs/120k miles as a special warranty. I run Mobil 1 5W/30 since original factory fill was FULL syn Mobil 1 in 2008. They later went to Dexos spec, but you should be running full synthetic. Before you even attempt the transmission fluid change be aware to the proper process. There is no dipstick - I can send you the detailed process which requires the car to be on a lift, level, motor running and at a specific trans temperature.
 
Messages
1,766
Location
Toronto Canada
I maintain my son's 2008 CTS with the 3.6 GDI V6. We use store brand synthetic 5W30 at 5-7,000 mile OCI's. Over 200,000 miles at present. The chain was replaced at 30,000 under warranty. I think there is nothing wrong with the design, they simply made a lot of bad chains. If you have a good one, there is nothing to worry about engine wise. The rest of the car is another story.
 
Messages
671
Location
florida
Originally Posted by IMSA_Racing_Fan
Hey everyone, newbe member here. I just purchased a 2012 Cadillac CTS 4 with a 3.6 liter V6 and all wheel drive. The car has 60k miles with no service record so I intend to replace every lubricant in the car. I intend to keep it indefinitely and my driving habits are a bit more spirited than the average Cadillac owner. These are my questions: The owners manual calls for 5W-30 semi-synthetic. I searched for common issues with this engine and found the timing chains tend to stretch causing various trouble codes to light up and the only fix is to tear it down and replace the chains and tensioners. I live in South Texas where the heat averages 100 deg F in the summer. Should I go with a higher viscosity such as 10W-30 or 10W-40 to provide more shock load cushioning on the chain rollers and preserve idle oil pressure? The owners manual states to stick with the recommended weights (of course it always says that but IMO the engineers aren't concerned with the vehicle past the warranty expiration). Should I flush it before the change? Transmission: Dexron VI I've ordered 6 bottles of Transtar ATF. Their website indicates this company manufactures GM labeled fluids. https://www.walmart.com/ip/ATF-Flui...-LV-SP-IV-SPH-IV-WS-FZ-ZF6-ZF8/126963350 Front and read differentials: 75W-90 with 4 oz of limited slip additive. Ordered Mobile1 LS 75W-90 and no additive. Transfer Case: This is my biggest question. Owner manual indicates Transfer Case Fluid GM PN 88861800 I called Mobile's customer support number, was transferred to a higher level of support, and the agent stated they list no fluid for this application. I found a topic on this board with a similar year and model vehicle and the final answer was either straight ATF or motorcycle engine oil as gear lube kills the carbon fiber clutch plates. If that suggestion holds am leaning towards a full synthetic H-D spec oil or just going with the factory fluid. I want to make sure the internals last. I have bottles of Lucas Transmission Fix and Lucas Oil Stabilizer on hand. Should I use these or leave them out? Thanks in advance. I've had success in the past keeping older vehicles running by going with my intuition and past experience as a service tech on vintage imports and dealership vehicles but this is the most complex vehicle I've tinkered with.
and yet you bought this anyway? why/ no one needs all wheel drive in Houston and the 3.6 engine has a long history of problems
 

IMSA_Racing_Fan

Thread starter
Messages
532
Location
Houston, Texas
"no one needs all wheel drive in Houston" Rain is common here. I didn't go to the dealership looking for this, I selected a less expensive, more utilitarian vehicle but they couldn't get it financed so the salesman plopped this one on the table and I was out the door nothing down no payments or interest for 90 days. Couldn't believe it because I was turned down by numerous finance firms a few months ago because my credit, while not bad, did not have enough on it. I think the Coronavirus has slowed down the economy to the point they need whatever sales they get.
 
Messages
5,365
Location
Fort Worth, Texas
Originally Posted by super20dan
and yet you bought this anyway? why/ no one needs all wheel drive in Houston and the 3.6 engine has a long history of problems
Troll much?
 

IMSA_Racing_Fan

Thread starter
Messages
532
Location
Houston, Texas
I looked for it, only sold in gallons! Thanks for the tip though. Went ahead and bought an equivalent Transtar product for 6 bucks and change. Now everything in the power train and drive train will be synthetic. Am I making a mistake? Guess it will be apparent down the road. https://www.transtar1.com/MVHV

Screenshot_2020-03-31-00-49-34-746.jpg
 
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Messages
600
Location
Earth
Mobil1 5w30 "vanilla" or EP at a 5-8k OCI based on how hard you've been driving it should be more then sufficient to ensure long life for the GM 3.6. Now transfer cases can be picky in older vehicles so I'd go with the GM fluid.
 
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