: ls6 rough shutdown engine noise



smackdaddy
01-23-08, 06:28 PM
I went and test drove a cts-v today. I was ready to bring it home after the test drive, owever when I shut the key off the engine shut off very roughly. It seemed like what some older cars used to do that I called dieseling. After shutdown the engine almost continues to run roughly for a few revolutions before it finally dies. It did this each time I shut off the key. Is this a normal trait of the ls6? Has anyone else ever noticed this rough shutdown condition? Should I be concerned or not? Thanks in advance for your help! If this is normal then I may be getting a new V, if not I'll keep looking for the right one.

LUVMY04V
01-23-08, 06:35 PM
I would be concerned for sure but if you can get a warrenty it doesnt matter

for the record mine starts and shuts off like a kitten waking up and falling asleep:D she purrs kinda loud though

SkullV
01-23-08, 06:40 PM
Some people have fixed this problem by changing out the motor mounts....I also remember there being something about the gears in the transmission that is said to make shutdown a little rough...dont take my word on that one though.

ssmith100
01-23-08, 06:40 PM
Broken motor mount........mine's doing the same thing. Once it's repaired it will be fine.

Shane

OldRoadDawg
01-23-08, 06:44 PM
I went and test drove a cts-v today. I was ready to bring it home after the test drive, owever when I shut the key off the engine shut off very roughly. It seemed like what some older cars used to do that I called dieseling. After shutdown the engine almost continues to run roughly for a few revolutions before it finally dies. It did this each time I shut off the key. Is this a normal trait of the ls6? Has anyone else ever noticed this rough shutdown condition? Should I be concerned or not? Thanks in advance for your help! If this is normal then I may be getting a new V, if not I'll keep looking for the right one.

Have it checked for bad motor mounts
Other threads with similar complaint:
http://www.cadillacforums.com/forums/cadillac-cts-v-series-forum-2004/100081-rough-engine-when-turn-off.html
http://www.cadillacforums.com/forums/cadillac-cts-v-series-forum-2004/115860-engine-shakes-when-ignition-turned-off.html

CadiKing2006
01-23-08, 07:05 PM
not broken! lol but wornout motormounts. They are replaced under warranty. Sadly in about 6 months that rought engine turn off will be back then another replacement. Warranty rules. After that good luck spending $1200 every 6 months or live with it

type911
01-23-08, 07:09 PM
Yup need to make an appointment myself.

Nick4208
01-23-08, 07:31 PM
Yeah mine does the same thing. Looking like after winter she will be going in for a few things.

smackdaddy
01-23-08, 07:55 PM
thanks for all the replies, makes me feel better about the purchase.

randycsvt
01-24-08, 01:42 AM
Mine does the same thing, but the dealer says my mounts are fine. Random ticks, shakes, rough idles, and dieseling like shut offs are somewhat normal for the LS series motors I have heard.

JimmyMack
01-24-08, 05:36 AM
Yeah, mine too. Dealer says mounts are fine.

ewill3rd
01-24-08, 07:35 AM
They all have a "run on" sensation on shut down but when the fluid leaks out of the motor mounts it can make it feel like it will shake your teeth out.
The mount(s) might be dead.
If the mounts are good you don't feel the vibration but it still shuts off the same way.
The mounts were on backorder the other day.

DRKSIDE
01-24-08, 10:27 AM
I had this problem. Replaced mounts and it was fine... for about a week. Now it seems to be getting rough again though nothing like when the bad mounts were in there. I also have a rough idle that was downright scary with broken mounts. New mounts fixed that too. Amazing what happens when you attach the motor to the car. ;)

odla
01-24-08, 11:48 AM
does anyone have a good mount i can have. Im thinking about getting some made. i have good conections with energy suspension. that will be my second choice. my first would be to prototype myself then maybe have them look at it.

SkullV
01-24-08, 01:35 PM
does anyone have a good mount i can have. Im thinking about getting some made. i have good conections with energy suspension. that will be my second choice. my first would be to prototype myself then maybe have them look at it.

UUC is supposed to be making some mounts for the engine and trans as well as bushings for the rear.

odla
01-24-08, 01:41 PM
ive heard that for a year seems like.

trukk
01-24-08, 01:42 PM
not broken! lol but wornout motormounts. They are replaced under warranty. Sadly in about 6 months that rought engine turn off will be back then another replacement. Warranty rules. After that good luck spending $1200 every 6 months or live with it

They can definately break. Ask me how I know :crying2:. Mine is starting to act up again. I'm currently on my 4th set (at 64k miles). I think I lead the league in busted mounts. I've been thinking about why I keep killing mine. I don't 'dog' my car. Spritied driving, yes, but flailing on it, no. I think the culprit is that I always rev match heel/toe in daily drving. I think that constant throttle blip, is putting the @$$-smack on the mounts. I'm REALLY looking forward to UUC releasing their poly motor mounts.

http://www.cadillacforums.com/forums/attachments/cadillac-cts-v-series-forum-2004/37590d1195322418-friends-dont-let-friends-drive-bad-motor_mount.jpg


-Chris

SkullV
01-24-08, 01:42 PM
ive heard that for a year seems like.

Yeah thats true, I'm calling Luke in 5 min to order a new shifter, I'll see what he says about it.

SkullV
01-24-08, 01:49 PM
Well I called and I forgot to ask...I'm sure he will chime in though!

odla
01-24-08, 01:51 PM
cool

odla
01-24-08, 01:52 PM
oops not cool lol

ewill3rd
01-25-08, 07:56 AM
I'll ask him about this today... if I remember. A bump would be good.

bcarv87
01-25-08, 10:13 AM
Whats up guys, my motor seems to do the same thing after shutdown with 25K on it and warranty is almost up :crying2: So I guess I should go to the dealer soon.

I was wondering if I could go to another dealer, one where I did not purchase the car, and have warranty issued done, looked at, etc. I bought the car about an hour away from where I live and theres another cady dealer where my buddy bought his V from about 1/2 Hr closer to my home. thanks for any input.

OldRoadDawg
01-25-08, 10:34 AM
.... with 25K on it and warranty is almost up
Why would your warranty be "almost up" with only 25K miles??

And yes, you can take it to any Cadillac dealer you choose.

bcarv87
01-25-08, 11:01 AM
Well I read in this thread that it happens every 6 months or so (rough shutdown) which is kind of hard to believe but want to get it done to see what happens with the new motor mounts, if thats actually true then I could possibly get them changed up again before the warranty does actually end which will be next year (09), so I was told by the cady dealer who sold it to me.
hope this clears it up, if not, sorry to confuse, I work the night shift and really tired but cant stay away from the forum.

bcarv87
01-25-08, 11:02 AM
ohh yea the warranty is 4 years or x amount of miles, if forgot.
I got an 05 btw.

OldRoadDawg
01-25-08, 11:15 AM
Well I read in this thread that it happens every 6 months or so (rough shutdown) which is kind of hard to believe but want to get it done to see what happens with the new motor mounts, if thats actually true then I could possibly get them changed up again before the warranty does actually end which will be next year (09), so I was told by the cady dealer who sold it to me.
hope this clears it up, if not, sorry to confuse, I work the night shift and really tired but cant stay away from the forum.


ohh yea the warranty is 4 years or x amount of miles, if forgot.
I got an 05 btw.

Not sure where that idea of the mounts going bad every 6 months comes from. My '04 has 37K and still has the original mounts with no shake on shut down.

Check out the sticky at the top of the forum page, become a supporting member:

http://www.cadillacforums.com/subscribe.html

then have one of the guys run your VIN history. You will know what has been replaced and when your warranty expires. Base warranty is 4yrs or 50K.

Gordy Petrovski
01-25-08, 11:16 AM
New motor mounts :cheers: get ur dun!!! I had the same prob.

bcarv87
01-25-08, 11:23 AM
Thanks OldRoadDawg for the info, I think im goin to see the dealer today If i have a chance.

tedcmiller
01-25-08, 11:32 AM
As may posters have noted, a certain amount of "dieseling" at shut off is common for the LS6. My previous '04 V exhibited this characteristic, and my current '05 V does too. However, an excessive amount could be an indication of a real problem. You (or maybe the dealer) will have to be the judge.

Wads56
01-25-08, 10:26 PM
I always just assumed that the dieseling after shut down was because of the massive flywheel the car has. 80lbs rotating at 700rpm takes a few seconds to stop moving:)

ctsv154
01-25-08, 11:55 PM
I always just assumed that the dieseling after shut down was because of the massive flywheel the car has. 80lbs rotating at 700rpm takes a few seconds to stop moving:)

My thoughts exactly!

Cadi V
01-26-08, 12:14 PM
Mine kinda does the same thing i might have to make a dealer appontment

syd
01-27-08, 04:13 PM
...most of it IS becasue of the flywheel. I'm sure the car is fine. After I changed to a lightweight flywheel this week, it shuts down as normal as a car with high compression, a hot cam, and stiff valve springs can. It's really just a thinly disguised race car engine honestly.