Hey all,

I've got a 99 silverado z71. I just got in a couple weeks ago. Since then, I've changed the oil and filter, fuel filter, rear end diff and so on. I noticed that on startup the oil pressure is slow to rise and that the motor will make noise until the engine does. I know this can't be good. Am I most likely looking at replacing an oil pump? Also, I have no idea how long this has been going on. Is there a chance there is damage left from this? Any advice? I don't have a ton of money to put into the truck.

Thanks,

Kyle

 

It depends on the noise you are talking about. What oil and filter did you use? The 5.3 as well as the 4.8 and 6.0 are known to make a start-up tapping noise which is piston slap. As bad as that sounds it is considered normal according to GM and will not cause any issues. Well I have to agree somewhat as I have had them with well over 200K miles and they still run great. GM also says that using up to a quart of oil between changes is normal. I think this is related to the piston slap and some oil getting by. Again as bad as all this sounds I still think this line of engines are the best, easiest to work on ones that GM has made.

 

Well if the tap is that bad make sure you have the right weight oil in your truck too

if its too heavy your engine cant pump it to the top of the engine like it should

 

I had forgot about piston slap. I had that issue on a 2000 chevy a few years back. This time I am more concerned because this truck has been abused more than my previous one. It has 300k on body and I'm told 145k on drivetrain. How do I determine if the noise I am hearing is piston slap or an issue? I just assumed there may be an issue because the oil pressure gauge starts off low.

The oil I am running is 10w 30. I believe spec is 5w 30. Not sure if that would cause any issues.

I appreciate the feedback! I am hoping it is just piston slap. Let me know what you guys think.

Thanks,

Kyle

 

Oh ya, filter was a microgaurd and oil was quaker state. Engine seems to run good and have decent oil pressure after a few seconds. Just with the oil pressure gauge reading low on startup has me wondering.