Cold Start Engine Knocking

[Mplanchart]

Hello Everyone,

It's a pleasure to meet you all. I hope everyone is enjoying their Sunday.

So I am having this problem with my 2002 GMC Sierra V6. 4.3 Liter. Every time I start the truck first thing in the morning or after I have not been driving the truck for 3-4 hours, I will hear this knocking sounds coming out of the Engine. It will last for 3-5 minutes until the engine warms up and then is quiet and it runs great. Oil pressure is good it does drop to the 20 PSI not sure if that's an okay level but that's the only thing strange thing I have been noticing from the truck. I checked the dipstick and it does have oil to it's required level. I am planning on taking this to a mechanic but I just want to know if anyone here had experienced this type of issue and if so what did you do to resolve it?
Truck just hit 120k miles.

Thanks,

 

[winger870]

GMC and Chev trucks have a history of Piston slap. I thought this was a 8 cyl issue who knows it may affect the V 6s. Do a google search for Piston slap on your vehicle.

 

[Mplanchart]

Hello Winger,

Thank you for the response. I took it to the mechanic today and I told him about the symptoms. He also mentions that could be a piston slap and funny that you say that, he also said that about the Chevy and GMC history of piston slap. I left my truck at his shop and he will be doing an inspection. I will keep the forum informed once I know the results.

Thanks,

 

[Mplanchart]

Hello Everyone,

I just heard back from the mechanic. The lifters of my truck are what is causing the noise. He told me that I could either keep driving the truck for a long time and keep a good maintenance on it or he could also change the lifters for $800.

I am going to save the money and ask him to do the job for me and the next 6 months. I will keep everyone updated once I get the job done.