: 2007 DTS Engine noise at start up help



speedydog
05-16-11, 10:24 AM
I just bought a 2007 DTS and when i start up whenever its cold (sitting for several hours or overnight) it sounds quite loud almost like a diesel (not as loud though) i brought to dealer and told me this is normal for northstars some are louder then others i have had northstars in past and never seemed this loud, it goes away after about 30-60 sec is the dealer jerking me or is this normal???

Skiller.
05-16-11, 10:37 AM
Yes, it is normal. It's called cold carbon rap. Take a look here: http://www.cadillacforums.com/cadillac-tech.html#full

Submariner409
05-16-11, 03:04 PM
"Normal" is a relative term in this case: some Northstars have cold carbon rap, most don't.

As Skiller posted, the "granny cars" seem to be the most prone to have the problem.

maeng9981
05-17-11, 01:19 AM
It could also be the sound of your A.I.R. Pump working. In this case it's perfectly normal to hear the pump running but if too loud, the A.I.R. Pump may be on it's last leg.

tateos
05-26-11, 02:44 PM
It could also be the sound of your A.I.R. Pump working. In this case it's perfectly normal to hear the pump running but if too loud, the A.I.R. Pump may be on it's last leg.

Good catch - I didn't think of that, but it fit's the time period described perfectly