Lower oil pressure

Hello everyone, I'm writing to tell you that my Chevrolet S10 pickup
is giving me trouble. The oil pressure gauge drops almost to zero, and the compression is also quite low. So far, I've changed the oil and filter, and that's the only symptom. The engine doesn't overheat, starts right up, doesn't shake, and doesn't emit much smoke. I was told it could be the oil pump or something with the filters in the oil pan. I'd appreciate any ideas on how to diagnose this problem.
Thanks in advance.

You need to drop the oil pan because air is getting in. Now try lifting the front of the truck really high, then start it. If the pressures rise, it means there's a leak in the oil pickup or pump. But you have to see if the problem persists after lifting it like that. You also need to check the camshaft bearings; they might be leaking

You need to notice two things to determine your problem
: 1. When you see the needle drop to zero, do the valve lifters start to rattle?
2. When the pressure drops to zero, remove the oil filler cap and observe if oil is splashing.

If the valve lifters rattle or the oil stops splashing, then your problem is indeed in the lubrication system.

Perform these tests and let us know the results so we can continue helping you.

Hi Argo, if it has an oil pressure gauge, check how it takes the measurement, whether it's through a Teflon-coated hose or copper pipe. To see if the pump is at least spraying something, unscrew its connection and have someone start the engine. If the pump is working correctly, it should spray a good stream of oil (cover it with a rag)

Well it sounds logical I will do the tests you recommend and I will give you news