ok got a major crisis here. i bought a 1000 dollar 2000 silverado 202,000 miles 5.3 and it seems like after i changed the oil the check oil pressure light ...

ok got a major crisis here. i bought a 1000 dollar 2000 silverado 202,000 miles 5.3 and it seems like after i changed the oil the check oil pressure light comes up on the message center. i ended up buying a new pressure sensor and breaking it so i went to the boneyard and picked out three more sensors installed two of them so far and the light still stays on and the gauge reads 0 at all times regaurdless of engine rpm. i wouldnt think that all these sensors are bad but i dont k now the test for them is there a voltage reading i should be looking at at the sensor? it also seemed to develop a tick or k nock so i thought it was the oil pump, but a friend told me if the oil pump was bad the knock would be horrendos. we ended up revving the motor hard and the noise went away we think it was a collapsed lifter that just filled back up with oil. i have a spare instrument cluster that i swappped into this truck to see if the gauge was bad and the original problem still persisted no pressure ive ran it at idle multiple times since and it hasnt seized up yet. the motor seems hard to turn over my hand compared to my parts truck which is identical in every way so im not sure what the problem is. a lot of people on the internet are saying that the problem is with the oil filter i bought a fram filter ive used these on many vehicles over the years and never had a problem. but id heard something about they dont have a antidrain back valve or they collapse internally. had heard that maybe changing the oil knocked something loose inside the engine and blocked a passage way for oil but i have no way of testing this. ive spent multiple hours searching the internet for answers and help from anyone would be great thanks in advance

I would find a mechanical oil gauge and go straight off the motor just to double check oil pressure.

Yes, I would do that as well, and I would refrain from revving the engine up really fast until I verified that it has good oil pressure. It sounds to me like you got the truck for a steal because the person selling it knew the engine had low oil pressure. They may have put some really thick oil (gear lube) in it to bring the pressure up. When you changed the oil you used regular weight oil and the oil pressure problem appeared.

A 2000 for $1000.00, that's a steal even if it did'nt have an engine, unless the body is trashed. I'd be careful not to spend too much $$ because you could go to the boneyard and get another LS engine. JMO

dont start it again till your sure you have oil pressure ( worst case take a valve cover off and turn the engine over a few times to see oil spray). i worked with a guy who forgot to fill a car up with oil after a oil change(yeah i know lol) and he said the the customer got 3blocks down the road before the engine .... disappeared. lol. i'd put my money on your problem being electrical. if you have a multi meter probe the sensor with the engine off then with the engine on, look for a change of ohms. that should at least tell you if the sensors bad or you have no oil pressure.

It could be electrical, but I wouldn't count on it. With the lifter noise associated with the loss of pressure on the gauge I'd assume the worst untill you can get a manual gauge and check it. Whoever sold the truck sold it that low for a reason. It would be a heck of a coincidence that the gauge decided to go bad right when you cahnged the oil and filter.

Putting a mechanical gauge on it is the way to go. Having said that, since you tried multiple sensors and even another cluster I'd just put a pump in it. You said the lifter noise went away after revving it hard... indicates weak fuel pump or oil galley blockage. Also, you said, the motor cranks harder by hand than your junkyard motor.

At this point I would put an oil pump in, degunk the motor, change the oil (again, you have to with degunk) and see where you're at. Hard revving could have damaged the engine, but you won't know until you put in the new pump.

It's probably got some worn bearings as well, maybe even scored pretty bad by now. I'd probably pull the pan and check them as well. That way you can also really clean the gunk out of the pan and also check the pickup screen for gunk obstructing it. I have the feeling this problem did not just start, so it may be worth checking it real good before dumping money in just an oil pump.

i wouldn't put to much into the lifter noise. the early 5.3's are known for lifter noise, mines had a tick tick tick since i got her 102,000 miles ago. pull the oil drain plug its got a magnet on it, you get chunks then you know if not buy a multi-meter.

If the only symptom was the lifter tick I'd agree with you. However, he said it showed good oil pressure until he changed the oil and filter. Taking all things he stated into consideration, his best bet is to use a mechanical gauge to determine if it actually has oil pressure. It's a relatively safe and inexpensive test (assuming you have or can borrow a gauge). You can still have damaged bearings due to low oil pressure and not have "chunks" of metal present on the drain magnet. The safest bet is to go ahead and check the oil pressure, then go from there if it's good. If I am wrong then the worst he is out is some time and a little effort. But, he will have peace of mind if he knows his oil pressure is good.