I have a 99 silverado 1500 with the 5.3 it was chattering when starting cold and taking a while to develop oil pressure.

I replaced the oil pump, pickup tube and o-ring with Melling parts. It was a worn O-RING that was causing a bad seal. I installed everything and the truck runs better than ever and there are no noises. it holds 60 psi cold and 40 psi warm BUT occasionally when the truck is not quite warm and not quite cold the oil pressure gauge will flicker above 40 psi?? it did this before with the old oil pump (which is to be expected) but its almost as if all the bouncing the gauge did when the pump was bad wore out the gauge itself??

just wondering if anyone else has this "flickering gauge" problem.

thanks

-nate

 

How many miles are on the truck? I have seen this in trucks around that year and a few years new. I'm not sure what causes it but one in particular, the needle would bounce from on side of the gauge to the other. Poor electrical contacts in the gauge is the only thing I can image would cause this problem. If you are worried about having a working gauge, they are not hard to replace, otherwise it's something you can overlook without any other problems.

 

The truck has 270,100 miles, but i have good reason to believe the engine has been rebuilt or replaced. when i replaced the oil pump the inside of the engine was very clean and sludge free with good even cross hatching still visible on the cylinder walls.

my dad has the same truck with 220,000 miles and has owned it since new and never had any problems with oil pressure or his gauge. BUT he does have some dash problems such as the odometer flickering on and off.

I too have heard these models are bad with wiring to the gauges and dash.