Almost since the engine was new (and before nitrous injection) every so often immediately at startup, I get a loud what sounds like a multi valve clatter. This summer it is happening more often. Anybody else with a Northstar has this condition? It only happens for like a second.

Same here Venom. I notice it only for a few seconds as well.

I will check mine out and get back to you. Like mthe new pic!

Same here never really noticed but I will listen a little more intentive

yup i have the same... but mine isnt just one start up...


I think the new engine is on order... gotta love warranty.

Done some researching through the Cadillac forums and came up with that it sounds like what they describe as "cold carbon rap". Rather than steal another forums text I am linking here to a nice read on the problem. The only solution seems to be a good injector cleaner and some real WOT'* after the engine is hot. After reading the thread I realized without my license my car hasnt seen much upper RPM exercising lately. Northstar tolerances are so close that they build up carbon very easily.

http://www.cadillacforum.com/m_2400/tm.htm

I do notice after a good **** run she is quieter and sounds healthier. I will sometimes coming off the Highway shift in to 2nd to create what he refers to as over run.. But on a engine as sophisticated as the LD8 is this really necessary ?