Why Does My 5.7L Gasoline Engine GMC Sierra Sounds Like A Diesel On Cool Below 50 Degrees Day Start Ups
Posted in Crank, Oil and Piston | Asked on Jun 17, 2010
I am the original owner of a 2000 GMC Sierra . Only 57,280 miles on it. Late last winter and continueing today… When the outside temperature is around or below 50 degrees Farenheit , I hear a loud clicking / knocking noise on start up and acceleration for about 1-2 minutes. Sounds as loud and just like a diesel engine. After the engine warms up slightly, it goes away.
Yes, before it is asked, the engine oil is changed on the recmnd. intervals and it is at full capacity right now. Funny thing about the oil changes though…the noise did not start until after an oil change last year at my usual garage. I wonder if they are responsible somehow for the noise, but no way to prove they were responsible…not even then.
Have been told and read this is normal for GMC Trucks, but I find it hard to believe, and can only think that loud noise is doing some sort of internal damage to my engine. Any advise, personal experiences, suggestions, etc. will be sincerely appreciated. Thanks!
There are 7 Answers
Piston Slap
sounds as though your lifters are making the noise.. some lifter noise in startup is normal as the oil has drained back into the pan
sounds like lifters I agree. Buy a bottle of Marvel Mystery Oil, add per directions to engine oil. That will clean the lifter oil passages if they are gummed up.
Good Luck.
http://www.pistonslap.com
May be a cracked exhaust manifold.
i have a 2001 gmc yukon. terrific truck and very well kept like yours. what you are probably experiencing is called “piston slap”. I too experience this with my truck and was uncomfortable with it. there was a bulletin put out by general motors in 2001 that recognized that certain engines (usually the 5.3 liter and 6.0 liter and not the 5.7 liter) were experiencing this rattle or “piston slap” at cold start and lasting a half minute up to two as oil circulated thoroughly. this slapping usually began to occur between 10,000 and 15,000 miles (like mine). general motors never fully divulged the cause of the noise but provided any complainants with an extended warranty free of charge for 6 years or 100,000 miles. general motors has fully corrected this issue on all engines from 2003 onward.
they maintain that exhaustive testing has indicated no permanent damage is being done to the engine and that no issues about engine longevity exist.
….. in my experience and from hearsay…. they are correct. i have zero issues at 89,000 miles. zero oil burning, no loss of power, no issue at all. it is very important to remember that all engines from all makers (other car a bmw) need at least 30 seconds at start up to allow for engine oil to circulate fully and that no engine should be pressed too hard if at all possible until it reaches full running temperature. If u change fluids, filters and sparks… use decent gas… your engine can be driven very hard for 200,000 miles, no worries. my next truck will be a 2008 gmc yukon. hope this helped.
probley weak valve lifters or even your oil pump