Valve clatter
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From: Purgatory, Pennsylvania
Valve clatter
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.
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Administratus Emeritus
Certified Car Nut
Joined: Jan 2006
Posts: 16,539
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From: Purgatory, Pennsylvania
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
http://www.cadillacforum.com/m_2400/tm.htm
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Joined: Sep 2006
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From: Somewhere south of Ottawa with your girlfriend driving faster then you.
all without creating a spectical of yourself and attracting the attention of cops. You can do it on most any freeway and stay within the 70-75 MPH range allowable. Once a week like this will keep the engine cleaned out and healthy and is DEFINITELY recommended for the Northstar in particular.
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 ?
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