coreyplant

Hi all, just wondering if anyone has exhibited this issue ? there were only 2 times thus far i started my car up and the weather was about 40-43 degrees outside i always let my car idle warm up for about 2-3 minutes on 2 occasions right after starting there was a loud severe engine knock noise, it sounded like it was coming from the rear left bank, the first time it happened i freaked out and shut the engine off then restarted the car and it went away, the second time it happened about 2 weeks apart same temperature and this time i just accelerated quickly for a second and the noise went away, obviously it's not a piston or rod issue because that would not stop or be intermittent, has anyone heard or seen this before ? my thought was of if there was some component not operating at that time causing this and the restart or romp on the throttle jarred it away but man was it supper loud just like a piston knock sound. i know of this sound because i have had this happen before blowing up a few cars in the past and having to build a few engines out, just weird not too worried the car is still under 2 more years warranty but taking it in would be ridiculous since it was an intermittent issue and no pattern of time or reason, I know about NPF on intermittent issues working for Service on trucks for 33 years sometimes you just have to see if it gets worse and more repeated to find the cause.
thanks for any input

jd864

Maybe the oil filter check valve didn't hold? Low oil pressure for a few seconds?

coreyplant

not sure, i remember the oil pressure gauge moving but both times the engine was started, it didn't stop for when the oil pressure raised, didn't like how it keep happening that's why the first time i shut it right off, the second time i romped on the throttle and it wend away
but the constant that sticks out is the noise sound like from the left rear of the engine like right in front of the left side firewall area.

2014GHIGGT

It wouldn't be the oil filter valve. Typically an engine that has a knock only when cold is usually a piston wrist pin and the noise is the piston slapping the cylinder wall. This condition typically goes away when warm. If it were a bearing it would get noisier when hot and more pronounced.

It could also be in the valve train. Most of the moving parts in these engines is in the cylinder heads.

boss man

I agree with this statement. These engines have a small history of knock due to piston wrist pin.
You may need to get louder exhaust to fix the problem.

coreyplant

yeah i hear ya, i'm not worried about it, i have 2 years and 26,000 miles left on my warranty, since it only happened 2 times, the answer i was searching for was of if anyone specifically has heard this in the left rear corner of the engine before ? as far as the oil pressure cause i can see that because it can act differently in different ambient temperatures, but for it being a piston or wrist pin knock, definitely not, I've built many engines gas and diesel for more than 30 years that noise once it starts it means there is some extra wear in that area and the slap or knocking as a result of that once it starts it very rarely goes away, it just keeps slapping or knocking until final damage separation of the two metals components then you will find the exact cause.
thanks everyone for your input. we'll see what happens in the future.