Engine banging at start up
#1
Engine banging at start up
Hi:
My 94z LT-1 has a mild to moderate banging at start up in cold weather but after 15 seconds or so it disappears. Im not a mechanic but it doesnt sound like a valve tap, something deeper. Is this something to worry about?
Like I said after about 15 seconds or so the banging stops and drives and sounds great.
Thanks for your input.
My 94z LT-1 has a mild to moderate banging at start up in cold weather but after 15 seconds or so it disappears. Im not a mechanic but it doesnt sound like a valve tap, something deeper. Is this something to worry about?
Like I said after about 15 seconds or so the banging stops and drives and sounds great.
Thanks for your input.
#8
Re: Engine banging at start up
Mine's been doing that since 170k or so and I thought was from oblong cast pistons but I never hear after 10 minutes of running
I've been running on borrowed time for a looooong time lol
I've been running on borrowed time for a looooong time lol
#11
Prominent Member
Join Date: Jul 2010
Location: Born on the Florida West Coast, now where can I retire?
Posts: 1,505
Re: Engine banging at start up
Badly worn crankshaft bearings will get noisier with hotter engine and oil. i.e. Quietest when cold, loudest when hot (especially when accelerating). Not likely in your case.
#13
Re: Engine banging at start up
Somehow, use of the word "banging" (even if "mild" or "moderate") sounds a lot worse than the typical gentle thud of piston slap. Could be oil that's too thick to circulate in extreme cold. But we still don't know what oil he is using, and whether it's particularly cold when this happens.
#14
Re: Engine banging at start up
I agree that banging is too harsh a word. A piston slap seems correct and more appropriate. I dont change my own oil and regularly have it done at a service station. I hope and trust they use the recommended oil. The "slap" only happens on very cold days and again only lasts 10 20 seconds or so. Then it disappears. My intent on this thread was to see if this is an indicator of long term problems and if there is anything I can do to prevent any further damage. With 140k miles, should I consider a synthetic oil?
#15
Re: Engine banging at start up
Piston slap of the type you describe is very common on the LT1 (and the LS1 as well). Does not do any permanent damage. Make sure they are using 5W-30 in cold weather. Makes no matter whether its synthetic or not.