light knock when cold?
Just curious if this is something that is inherent with the hemi? It's been in the teens (farenheit) in the mornings here. We usually use the remote start so it isn't too obvious by the time it's warmed up and we go out to drive, but if started when cold it sounds like a mild engine knock that pretty much goes away after it's warmed up (approx 10 minutes). I'm not asking for diagnosis, just curious if something on this engine is prone to causing something like this? I've personally heard this same sound on other vehicles that have been caused by the upper valve train, engine bearings and/or exhaust leaks. We have 23,000 highway miles on this 2013 D/RT 5.7 Hemi.
Thanks for any thoughts,
Jeff.
Thanks for any thoughts,
Jeff.
Read the response directly above your post.
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The light knocking noise you here when starting the Hemi cold is know as piston slap. I think that the Hemi use's forged pistons and this noise would be normal. My wife's 2007 300 C Hemi and my 2012 Durango all have that sound. Drive slow for a few miles and like he said the noise goes away. Not to worry.
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Last edited by Crankshaft57; Jan 16, 2015 at 11:17 AM.
piston slap is different from engine knock. It can cause some issues in the long term, the noise is from the piston having room in the cylinder to move more than just up and down(PistonSlap.com), since i like to drive all my vehicles into the ground, this is disappointing. somewhat poor build quality on my hemi.
Well, I had a 1984 Z28 Camaro that I built a 355 cid engine for on a 150 shot of nitrous oxide. I used Manley forged pistons and when I started it, it sounded like a diesel engine. That engine now has over 70,000 miles on it with many pushes of the button so I say to you again "Not to worry".
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