Sorry, I really need help. No oil pressure, Kangoo

I repaired a Renault Kangoo. Engine code: E7J0634. 1.4L, 75 HP, 8V, manufactured in 1999. Before the repair, the issues were: oil leaks everywhere, the oil pressure light flickered when the oil was warm and the engine was idling, high oil consumption, and blue smoke.

I started by replacing the head gasket, grinding the valves, re-facing the cylinder head, and installing new valve stem seals. Then, I replaced the oil pressure sensor, adjusted the valve clearances, and changed the oil and filter. However, the oil pressure light still flickered when the engine was warm and idling. So, I measured the oil pressure, and found that it was 2.5 bar at idle when cold, but 0 bar when warm. I then replaced the oil pump with a new one from Renault. I also replaced the main bearings and connecting rod bearings. The old bearings weren't worn or damaged, but they were rough due to the lack of oil pressure.

Now, I started the engine, and what happened? Exactly, there was no oil pressure when it was warm... The oil pump is driven by a chain connected to a sprocket on the crankshaft. Does anyone have any ideas? I am at a loss!

Have you already checked the simple things, like a strainer before the pump, and possibly clogged oil channels?

The strainer of the old pump was quite clogged with debris and seal remnants. However, I installed a new pump with a new strainer! And I cleaned everything thoroughly. If there's no oil pressure when the oil is warm, then no channel can be blocked, right? Otherwise, it would be the opposite: no pressure with cold oil and pressure with warm oil. I've been wondering if the bypass valve of the oil filter might be broken. This valve controls the oil flow through the oil filter. If it's blocked, the oil would be pumped unfiltered. But does the engine have something like that? I've only learned about that in school so far.

If the main and connecting rod bearings were damaged, then the auxiliary pump must have definitely been running dry at some point, right? Otherwise, the pressure would have been lost. What were the warehouses like?

Hi,

In Renault vehicles: is the pressure regulating valve integrated into the oil pump, or is it located separately and screwed in somewhere (e.g., Oil filter holder.

Take a look at that, and make sure the piston isn't stuck.

- Cold "thicker" oil pressure.
-Warm, "thinner" - nothing -

Best regards,

I completely disassembled the cylinder head and overhauled the necessary parts. The camshaft and everything else looks good. Could it be that the rocker bridge is mounted incorrectly? Or, someone may have already done this work after a timing belt failure, which I could tell from the valve marks on the piston crown and the Elring head gasket. The oil pressure valve is in the new oil pump. I meant the bypass valve, if such a thing exists.