[SaveTheManuals]

Bump from the dead. Unfortunately not fun updates...2 things have surfaced:

My driver side rear axle seal is leaking. Passenger side is not. Last time I had these done was at 44,000 miles (both were done under warranty), car now sits at 67,300. Having adopted the diff vent theory I was always good about checking it regularly to make sure it was clear, but at some point it got away from me and one day I looked under the car and saw the leak. Even when I used to check it regularly, whenever I threaded it out there was usually a little "hiss" sound like vent removal was letting built-up pressure out (which means vent wasn't doing its job as has been theorized). I did finally cut like 1/3 off of the little spring & removed the rubber stopper disc. The last time I removed the vent to check it there was no hiss so I assume it now works. Anyway ever since I bought the car in 2017 there was a faint high pitched whine from the diff. Within the last two months the pitch of the whine has lowered and gotten a little louder. I don't know if this sound change is due to the fluid level being low, the fluid being old, or if the gears or whatever have just worn down more?

Regardless, given the newfound leak, I figured I should add a little gear oil back in. I went to my Cadillac dealer and parts dept had no 75W-90 w/friction modifier on site, but a nearby Chevrolet dealer did. I bought 2 bottles ($40 each) and grabbed my 2 way Harbor Freight pump, removed the fill bolt, and attempted to pump in fluid. I had read things here and watched a video or two but in actually doing this I couldn't tell how far to stick the hose inside the diff...if I did it one way it barely went in but if I angled it another way it went much further in. I didn't know how far to insert it, and whether how far I had stuck it in was taking up real estate that should have been taken up by the fluid? On top of that it seemed like I was pumping in way more than what had had leaked out onto the diff housing (used nearly half of a quart and there's no way that much came out). Then my cheapo pump started leaking oil and a small stream was coming out of the fill hole so out of frustration/annoyance I called it good and closed it up. I don't know, I thought this procedure would be pretty simple/straightforward but as you can see there was confusion for me.

Dealer said they can replace the seal all in for $880 (seal parts & labor = $654, fluid parts & labor = $227. The seal P&L I get, but the fluid I questioned at first since a quart is $45 and that's all it needs, but then I started thinking well maybe they flush it with a few quarts of fluid and a machine is used to do that? They're probably not under there with a hand pump haha. I dunno, I can live with the cost because I just want the diff, seals, & fluid to all be in good order again.


The OTHER update is my radiator that has been leaking for quite a while now, of which I have just been topping off fluid every week (car only really gets driven 3-4 times a week). But the leak has gotten worse over time, and I am tired of having to spend $25 on the proper coolant over and over. I decided to also have the dealer quote replacing the radiator. First off, they said they could not get a factory radiator since they had been discontinued for manual ATS's, but that the radiator designed for the automatic had the same flow, would bolt up, and work fine. The only caveat being that it has a transmission cooler line that will not be used on my car since it's manual, and it will just get capped off. Anyway I have researched radiator replacement (to assess if I could do it) and I knew it would not be cheap since you have to take off the front bumper cover, etc. and my concern was fulfilled when they told me parts & labor would be $1,950. Quite a contrast to replacing the radiator on my 1999 Accord V6 coupe which is like $150 for the radiator and super easy to get to, but that is modern cars for ya.

I have considered using a shop I have taken my other cars to but with all the specialization with the radiator in the ATS and my manual vs automatic situation in particular I don't feel as comfortable using them. And my dealer is really great. And it would be a pain to pull the car from the dealer to let the shop look at it only for me to confirm it's better off at the dealer, it's already at the dealer too for the diff stuff. From the limited info that was out there about radiator replacement, I don't think I'm up for DIY'ing it either (maybe in my younger years I would have haha). I researched using an aluminum unit but the only drop in is ZZP's but I read that people who bought it said it leaked and/or was out of square. Dealer wouldn't install that anyway. Overall this nearly $20 figure is a bit tough to swallow, I wish this could have been closer to $1,500 but it is what it is. I only hope there was some type of revision with the OEM units and I won't have this issue again.

If you read this far, thank you. Overall I really can't complain, I mean in 7.5 years and ~44,000 miles, I have not had to put any serious money into this car until now. It's been a champ and I want to keep it long term so I will likely be dropping ~$3,000 into it this week to address its issues.

 

[hoser450]

Sorry about the issues, that’s a bummer. But like you said, not bad for the time you’ve had it and the age.

 

[SaveTheManuals]

Getting the radiator replaced and the driver side rear axle seal replaced ended up coming out to a few hundred less than the estimate. I notice when I get rear differential fluid service performed that on the invoice there is a blurb about how if I get a B&M fluid service done every 30k miles, in the event of a replacement diff being needed there is a credit up to $2000. Hopefully I never have to do that but if I do then that, if I am reading it correctly, could potentially be a big help.

In other news on the way into work this morning my CEL came on. Wife is bringing my OBD scanner later today. I did not hear, smell, or feel anything different, and the car drove like it always has, so here is hoping it is something minor.

EDIT: CEL code is p015B. Hoping this just means I need to replace the o2 sensor.

 

[DavidATS]

Getting the radiator replaced and the driver side rear axle seal replaced ended up coming out to a few hundred less than the estimate. I notice when I get rear differential fluid service performed that on the invoice there is a blurb about how if I get a B&M fluid service done every 30k miles, in the event of a replacement diff being needed there is a credit up to $2000. Hopefully I never have to do that but if I do then that, if I am reading it correctly, could potentially be a big help.

In other news on the way into work this morning my CEL came on. Wife is bringing my OBD scanner later today. I did not hear, smell, or feel anything different, and the car drove like it always has, so here is hoping it is something minor.

EDIT: CEL code is p015B. Hoping this just means I need to replace the o2 sensor.

Years ago the local Cincinnati dealer (think you are in Cincinnati?) replaced a diff seal under warranty and with it they replaced the fluid with a non GM fluid, I think BG, since I have an LSD diff I am not sure if they used the wrong BG fluid or what but it would try to lock up (limiting slip), around tight corners. I took it back, explained how this just started with the new fluid, they said the fluid shouldn't be the problem but after they replaced it with the correct GM fluid everything worked correctly.

With the very few ATS's with LSD not sure where the problem came from, wrong type of non GM fluid or the company didn't make the correct fluid.

 

[gmorris_89]

I'm sorry if i missed it, but is there any write up regarding the grille? i really like it, looks very good. also curious how you got the oem accessories rear diffuser

 

[SaveTheManuals]

Years ago the local Cincinnati dealer (think you are in Cincinnati?) replaced a diff seal under warranty and with it they replaced the fluid with a non GM fluid, I think BG, since I have an LSD diff I am not sure if they used the wrong BG fluid or what but it would try to lock up (limiting slip), around tight corners. I took it back, explained how this just started with the new fluid, they said the fluid shouldn't be the problem but after they replaced it with the correct GM fluid everything worked correctly.

With the very few ATS's with LSD not sure where the problem came from, wrong type of non GM fluid or the company didn't make the correct fluid.

Hmm interesting. Yeah you never can be 100% sure about people doing their job correctly, especially these days. But just to drive it home I did verify with them the car would get the correct fluid with the LSD friction modifier and they said they pick out fluid by VIN so there should be no mistake (I think the service writer wrote it on the ticket just to make me feel better haha). But of those that then relies on computers doing their job correctly, pulling the right data for the technician.

A mislabeled bottle seems like a freak thing, if that's what happened. Maybe it was misformulated? Or they used the wrong one? Hopefully that was a one time fluke thing for you.

What does it feel/sound like if the car is trying to lock up around a tight corner?

I'm sorry if i missed it, but is there any write up regarding the grille? i really like it, looks very good. also curious how you got the oem accessories rear diffuser

Thanks. Hmm there may be some info in the preceding pages, as well as in other grill threads on the site. But what I did was buy a spare OEM grill off Ebay, I took it apart and cut it up. I bought a mesh piece from custom car grills . com and followed their DIY video to cut/form it to fit. I had some of the trim painted and bought an emblem to paint as well. Then I put everything together.

I thought the hard part was done, but then I had to remove the front bumper cover and the factory grill, and it was a job with all the screws and clips.

I kept an eye out for the factory optional accessory ground effects kit, one day found what I thought was the whole kit on Ebay and ordered it. It came from a dealer in another state but their part number or description were wrong and I was only sent the front lip and rear diffuser and the rockers were missing.

 

[DavidATS]

Hmm interesting. Yeah you never can be 100% sure about people doing their job correctly, especially these days. But just to drive it home I did verify with them the car would get the correct fluid with the LSD friction modifier and they said they pick out fluid by VIN so there should be no mistake (I think the service writer wrote it on the ticket just to make me feel better haha). But of those that then relies on computers doing their job correctly, pulling the right data for the technician.

A mislabeled bottle seems like a freak thing, if that's what happened. Maybe it was misformulated? Or they used the wrong one? Hopefully that was a one time fluke thing for you.

What does it feel/sound like if the car is trying to lock up around a tight corner?

My guess is there is a standard BG diff for the ATS with the LSD being such a small part of the population nobody thought about it. Especially with going farther north, take out all the AWD's, every trim but Premium for the automatics and then the manuals and they likely almost never see an LSD. First time I took my car for the service at the dealer they said they were going to rotate the tires, I pointed out rears are wider than the fronts and they told me I was wrong.

For what it sounds like when it tried to lock up on tight corners (parking lot or u turn), felt and sounded like someone jabbed at the outside rear wheel brake for a split second, was noticeable that there was something wrong. Forgot that it also happened to a BMW I used to own, independent shop used the wrong fluid on that one also and it did the same thing.

 

[DadillacATS]

Nice to see youre still around here. Sucks about the issues with the car. Mines leaking oil and coolant. At the dealership now. 3100$ later i should get it back some time this week. It only gets driven once a week if that, unless its snowing. Another 6 months and its paid off. cant wait.

 

[SaveTheManuals]

Somehow my CEL turned off and the p015B code is gone all on its own...weird.

Nice to see youre still around here. Sucks about the issues with the car. Mines leaking oil and coolant. At the dealership now. 3100$ later i should get it back some time this week. It only gets driven once a week if that, unless its snowing. Another 6 months and its paid off. cant wait.

Yea, you too. I lurk on FB more now but I guess I'm kind of old fashioned and still prefer forums.

True the issues were not exactly fun, but at the same time in 7.5 years and 45k miles it's the only serious money I've had to put into the car and otherwise it's just been fluids, tires, etc. So I can't complain too much. Hope nothing else happens for a while though.

Where was your oil leak? Think I saw on FB your coolant leak was from something on the back of the engine? That's not a fun bill either, but hope your car is good after that. The day you get your car paid off is a great feeling for sure. Also the day I realized I never want to have a car payment again haha.

 

[DadillacATS]

for real! no car payment is going to be nice to stack that away for more family related activities and trips.

Valve cover gasket was the source of the leak, not bad, but bad enough it was starting to drip. coolant leak was terrible, i am glad thats fixed. drove the car hard once it warmed up on the way home ( about 30ish minute drive ) and then parked it in drivway. sat for two hours then i had to go pickup one of my kids from school. not a drip.

 

[Crusher103]

Another long thread like mine! Checking in.

 

[SaveTheManuals]

Yuuuuuuuuuge update.




I bought logo door lights. I resisted for a while but they finally got me. It's a cheap thrill, what can I say. I do kinda wish it was just the logo though, the script has always been a little "old man" for my liking which is why I eliminated it everywhere else on the car (except the rear bumper trim piece obviously). The clarity is pretty good too, surprisingly. We'll see how long these last...

20250605_182030 by C B, on Flickr

In other news I got a flat (my 1st ever?🤔) a week ago. We had just dropped the kids off at my wife's parents' house so we could go out for our anniversary. We were driving back to the house on the highway and I heard a little thump sound and I thought I must have ran over a small rock or something, but a few seconds later the car started to feel a bit wobbly and I heard more tire noise, at which I point I knew it was going flat. I had just passed an exit and there is no way in hell I was changing a tire on the side of the highway (too many stories of people getting smeared by drivers who aren't paying attention), so I got to the right-most lane and then stopped & slowly reversed up the entrance ramp of the prior exit so I could change the tire near slower traffic. I was really paranoid about my rim getting ruined, but the flat tire took all the abuse.

The crazy thing is I had JUST put the 19's back on the day prior, which I had JUST bought new rear tires for, and one of the rears got punctured & went flat. AND it was just before my wife & I were about to go out for dinner, which is a rare occasion that we get to go out. I was pissed at the uncanny-ness of it all. However, I will say, contrary to before this event I am now a believer in buying the replacement warranty when buying new tires. I'm scarred now hah.

The puncture

20250622_193602 by C B, on Flickr

The culprit I found later stuck in my fender liner. What the hell is this?

20250626_084526 by C B, on Flickr


Also I just had a manual transmission drain & fill service done at my Cadillac dealer, pretty reasonable at $144.

 

[72chevman]

Wish I could find the Diffuser you are running. I truly dislike the satin black OEM plastic one.

 

[SaveTheManuals]

Wish I could find the Diffuser you are running. I truly dislike the satin black OEM plastic one.

I only ever saw one being sold individually, it was on Ebay a long time ago. I just spent a few minutes searching & nothing came up. Some dealership could have one sitting somewhere in their inventory, hard to know.

You could maybe find an extra factory diffuser for cheap and try painting it...

 

[DadillacATS]

Glad to hear the wheel wasnt banged up and you guys didnt have a blow out and spiral.

Door lights look good! If it ever goes bad, I know of a set of OEMs that work with tiny bit of work

 

[Crusher103]

I have similar door lights. They were like $40. Keep a few them around mine did not last too long maybe like 2 years then i had to replace them. It stop saying Cadillac, i was upset. 🤣

I got Ricer-ish idea though if one of us can figure out how to do it, dont judge me lol. Mod the puddle lights in the mirrors so it can also read Cadillac, but it also comes on when you hit a certain amount of boost. So like my car currently will hit about ~20lbs. I'll see 16-17lbs all the time so I don't want it on for that that could just be normal driving but once it hits +19lbs, lights come on.

 

[SaveTheManuals]

Between the 3rd brakelight, both tails, & both reflectors I felt like it was a little much on the rear end with all the red lenses. I just replaced the reflectors with these smoked clear reflectors for a different look to simplify things a bit. After installation I realized they sort of make the rear diffuser area a little more prominent, between the smoked lenses and the gray of the rear diffuser all blending together.

20250707_164530 by C B, on Flickr

Glad to hear the wheel wasnt banged up and you guys didnt have a blow out and spiral.

Door lights look good! If it ever goes bad, I know of a set of OEMs that work with tiny bit of work

Thanks man, me too.

Cool, always appreciate the heads up with your knowledge of good OEM+ stuff.

I have similar door lights. They were like $40. Keep a few them around mine did not last too long maybe like 2 years then i had to replace them. It stop saying Cadillac, i was upset. 🤣

Haha

I got Ricer-ish idea though if one of us can figure out how to do it, dont judge me lol. Mod the puddle lights in the mirrors so it can also read Cadillac, but it also comes on when you hit a certain amount of boost. So like my car currently will hit about ~20lbs. I'll see 16-17lbs all the time so I don't want it on for that that could just be normal driving but once it hits +19lbs, lights come on.

Only thing is the puddle lights are only visible in evening/night, but I guess it just wouldn't be seen during the day. And they shine on the door so I'm not sure how well it would show up on different exterior colors. Hey, interesting idea though hah.

 

[DadillacATS]

those reflectors look good! like you said, blends right in

 

[GrimATS]

Hey man, been following your progress for awhile and I was wondering if you remember the part numbers for the v rockers and extensions? Getting ready to order mine and wanted to make sure I got the correct ones. Thanks

 

[SaveTheManuals]

Hey man, been following your progress for awhile and I was wondering if you remember the part numbers for the v rockers and extensions? Getting ready to order mine and wanted to make sure I got the correct ones. Thanks

I just went to a GM parts website to get the numbers. I entered 2016 ATS V and clicked on Exterior Trim - pillars, and the list with part diagrams/numbers came up. You just have to make sure you get the sedan rockers if you have a sedan, and coupe if you have coupe.

https://www.gmpartsdirect.com/v-2016-cadillac-ats--v--3-6l-v6-gas/body--exterior-trim-pillars