: 2010 CTS engine noise at cold start



motorhead81
06-23-13, 09:59 AM
Anyone have any info on what to me sounds like an exhaust leak at startup that lasts about 20 seconds? Once the RPM's drop from a cold start, the sound goes quiet. I took it to the dealer & they say it's the lack of oil getting to the timing chain at startup. Sure sounds like an exhaust leak to me that seals after 20 seconds as things heat up? Seems like a Caddilac should be a bit more refined than to sound like a rattling 4 bang'er for 20 seconds at cold start. You can't hear it from inside the cabin, but from outside it's a bit much.

Twentybucks
06-24-13, 08:38 AM
Did the dealer say that the lack of oil can cause damage at some point?

blankster
06-24-13, 08:49 AM
On my 2010 the direct injection is a little noisy at startup until things settle down a bit after the fuel system charges up.

C "T" ess
06-24-13, 10:14 AM
If it only lasts 20 seconds I wouldn't worry about it. As blankster says' a little noise on start up is to be expected. You shouldn't condemn the brand for this.

Twentybucks
06-24-13, 10:40 AM
My 2010 CTS4 3.0L does the same thing, I little noisy for about 5 - 10 seconds then everything quiets right down. I guess my only concern would be that if it is an oil issue then parts, timing chain or whatever is making the noise might wear out prematurely because lack of oil. Hope not.

tinman
06-24-13, 10:48 AM
Have someone start up your car for you when cold. Climb under that baby and try to find the noise up close and personal. Don't have your wife do it if she knows your life insurance is paid up.

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http://http://www.cadillacforums.com/forums/2008-2013-cadillac-cts-general-discussion/312930-ticking-sound-3-6-again.html (http://www.cadillacforums.com/forums/2008-2013-cadillac-cts-general-discussion/312930-ticking-sound-3-6-again.html)

btlfedcts
06-24-13, 10:58 AM
It's not an exhaust leak or a problem.

In order to meet some of the SULEV emissions regulations (especially FTP Bag 1 numbers) the vehicle has a high idle at cold start to help get the catalytic converters to light off. You should notice this with either of the DI 3.0 / 3.6L motors when they are started below a designated operating temperature (varies by calibration year and engine model.)

99flhr
06-24-13, 11:09 AM
The oil drains to the sump when parked. Can`t argue with gravity
Picked up by the pump and you definitely hear the difference after it makes a full circut
The lifters and cam chain tensioners are now pressurized and the parts they control, quiet down

Just the way engines work , not a defect and nothing to worry about.

Z71
06-24-13, 12:23 PM
Never heard any noise yet in 4+ years with my 2009 3.6L, no cold start rattle or anything, oil pressure is instant. Maybe try a better oil with higher film strenth. I alwys use 0W-30 100% synthetic in all me vehciles, the CTS4 and the Denali.

blankster
06-25-13, 10:54 AM
On Corvette's we would turn the key to the "on" position to charge the fuel rails then start it. Again I think you are just hearing the system charging-up for a cold start which runs a bit rich to heat the cats.

tinman
06-25-13, 11:15 AM
On Corvette's we would turn the key to the "on" position to charge the fuel rails then start it. Again I think you are just hearing the system charging-up for a cold start which runs a bit rich to heat the cats.

Ha! Reminds me of my old MGB. I would turn it on and hear my fuel pump pressure up as well. About half the time I would turn it on and NOT hear my fuel pump pressure up (thanks, Lucas). That's when I had to get out of my car with the ignition "on", open the trunk, grab my dedicated rubber mallet and give my fuel pump the prerequisite slap with that rubber mallet! :thepan:

motorhead81
06-06-14, 08:22 PM
Thanks for all of the replies, I'm gonna take the advice of several replies and consider it a non issue.

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I think the dealer was wrong, I think the post that stated it's the fuel system / cat converter is correct. From under the car the noise seems to resanate from the cat converter.

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True! Good call by the way, seems like it's the cat conv area, normal noise I guess.

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I believe you nailed it, thank you. I can hear the noise from that area.

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Yep, I think that's all it is, I appreciate everyones replies

tinman
06-09-14, 08:51 AM
Are ya' sure, now? :bonkers:

next2pool
07-02-14, 11:14 AM
Anyone have any info on what to me sounds like an exhaust leak at startup that lasts about 20 seconds? Once the RPM's drop from a cold start, the sound goes quiet. I took it to the dealer & they say it's the lack of oil getting to the timing chain at startup. Sure sounds like an exhaust leak to me that seals after 20 seconds as things heat up? Seems like a Caddilac should be a bit more refined than to sound like a rattling 4 bang'er for 20 seconds at cold start. You can't hear it from inside the cabin, but from outside it's a bit much.

It is a normal issue. On cold start they pour fuel to it to light off the convertors and together with a high idle it causes that exhaust tone.