[CadiIIacVic]

Just wanted to help out some people just in case alternator issues come up. I recently have done some research on an alternator issue that I was having. But couldn't find any information on here using the search function and very little on internet.

Most or all Cadillacs from 2014-2020 ATS,CTS, XTS, CT6 have an Overrunning Alternator Decoupler pulley and they can go bad causing Battery Saver Mode to activate and your voltage to drop. If you're getting this message check your OAD before replacing the alternator.

You will need to buy or rent the tools to replace this pulley.

Here's the Part#
CONTINENTAL 49986 ATS,CT6,CTS,XTS

Picture of my damaged OAD

Hope this helps.

 

[emmidad]

Wow great info thanks. Who knew a pulley could be so complicated. How can we tell the pulley is the problem rather than the alternator?

 

[CadiIIacVic]

Wow great info thanks. Who knew a pulley could be so complicated. How can we tell the pulley is the problem rather than the alternator?

The sound it makes is like a loose belt and metal on metal grinding it sounded awful. Also the dust cap will not be there not sure if bearings hit it off or it melted off.

 

[FTSS]

Great intel, thanks. I'll save for 'future' need.

 

[RudyF6]

That's a strange design indeed.
What would the reason be for such a complicated (almost criminally so) alternator pulley?

 

[dbphelps]

Actually, it is all about "efficiency". It basically allows the alternator to free-spin when you let off the throttle or the rpms drop drastically after a shift. That way the alternator is not being dragged down (which takes power to not only rev it up but to drag it back down faster than it would naturally spin-down) on transitions. It is still being pulled up to higher rpms, just that it is allowed to spin-down to lower RPMs on it's own.

 

[CadiIIacVic]

So...here was the break down of everything and why I ended up replacing the alternator instead. I just want to say that the original alternator is still good.

So the pulley was going to be $83 w/tax and the tool kit was $53 w/tax. Shipping would have been $60 for next day delivery so I was sitting at $196.

A brand new OEM alternator from Rockauto GM 84542722 was $230 + tax and shipping $261.12. It was a no brainer for $65 dollars more I got a brand new alternator.

Now this may not be ideal for everyone especially if you can find the pulley locally you can save money. In this instance for me it was just better to replace the alternator. If you're wondering the alternator is a piece of cake. (2) 13mm bolts hold it on.


Remove the Negative cable on battery 10mm.

Remove engine cover *T30 bolt on the left oil cap on the right lift and pull off.

Remove air intake tubing loosen the (3) or (4) 8mm clamps and pull off.

Remove the belt the 15mm bolt on the tensioner pulley is right above a/c compressor. Pull towards passenger side belt will loosen and remove.

Remove the black harness clip first before removing the bolts.

Remove the (2) 13mm bolts after this the alternator will be stuck due to friction fasteners that are on the alternator. These fasteners get pulled towards the bolt as they are tightened. You will have to tap, wiggle, or pry the alternator to get it unstuck. Be careful with the wire UNDER the alternator it's small and may get in the way. I'm not sure what sensor it is but it's their and the alternator can land on it.

Remove the wire that is attached to the back of the alternator 13mm it is hard to break loose. You will need to hold the alternator with one hand and break it loose with the other hand.

The new alternator fasteners will be pushed out so installation is super easy and YES you can move the fasteners up on your old alternator to make installation easier if you're just replacing the pulley. Here are pictures of the two fasteners...
Fastener1 Fastener2
Fastener3 Fastener4

Now reverse the process and you're done.

So just some things I ran into if you're doing this and have to wait a few days for parts remember there is no power after disconnecting the battery so if you close the trunk there is no getting in easily. You'll have to send a little one in to pull the trunk release or use a hanger...like I did.


Well that's it good luck peeps...

 

[dbphelps]

CadillacVic, great write-up and excellent coverage of all the "look out for"s.

A couple of things of note, the bolt on top of the engine cover is a T30, not T40.

Also, the "fasteners" you mention on the alternator are called bushings. They slide in and out of the bores that are machined into the alternator so that there is a solid mounting of the alternator to the engine. They take any sort of stress off of the casing, thus the casing can be made lighter and will not be deformed when installed which should allow for better thermal expansion/contraction and overall longer alternator bearing life.

Just pointing out if you want to edit your post for those points it would be a great definitive guide for alternator replacement in these vehicles.

 

[CadiIIacVic]

CadillacVic, great write-up and excellent coverage of all the "look out for"s.

A couple of things of note, the bolt on top of the engine cover is a T30, not T40.

Also, the "fasteners" you mention on the alternator are called bushings. They slide in and out of the bores that are machined into the alternator so that there is a solid mounting of the alternator to the engine. They take any sort of stress off of the casing, thus the casing can be made lighter and will not be deformed when installed which should allow for better thermal expansion/contraction and overall longer alternator bearing life.

Just pointing out if you want to edit your post for those points it would be a great definitive guide for alternator replacement in these vehicles.

Thanks for the information I went ahead and edited the T40 to T30. Now the fasteners I will agree that they are bushings BUT...I will argue that they ARE fasteners as well ONLY because they are treaded and it is the only object the bolt has to fasten to.

 

[dbphelps]

Thanks for the information I went ahead and edited the T40 to T30. Now the fasteners I will agree that they are bushings BUT...I will argue that they ARE fasteners as well ONLY because they are treaded and it is the only object the bolt has to fasten to.

I got ya... Then those would be considered "bushing nuts". Basically threaded bushings that are kept from turning by built-in stops. I have seen those as well before. Honestly, I have seen them referred to industrially (automated manufacturing background) as "bushings".