I think I may have managed to awaken the gremlins in my Disco. It's an 02 with about 115k on it. I got my Disco about a year and a half ago and it's always run well. Slight tapping at startup and when accelerating that subsides after a while. I managed to get all the indicator lights off and did a few of the standard fixes (heater plate, drive shaft, ABS shuttle valve). I'd been dealing with a slow external coolant leak for a while that I feared may be a head gasket, but as it turns out it was just the front cover leaking from the top right. So I set about fixing it.

I ordered a new front oil seal, front cover gasket, oil pan gasket, and a water pump. I managed to get everything apart using RAVE, replaced my seal, fit the new gasket, and I ensured that it was properly aligned from underneath the vehicle while I slid the cover back into place. I got everything back together and all the bolt torqued to spec and refilled the coolant and oil with 5w40 like I've always used. I went to fire it up and everything turned over and fired like it should, but there was a low oil pressure light on and the engine was making what I could only describe as a chugging sound, almost sort of like a diesel engine or a washing machine. It didn't sound like a grinding, tapping, or knocking sound, almost sort of like a misfire but no code was being generated for a misfire.

I didn't managed to get oil pressure readings yet (stupid mistake), but when I revved the engine a bit the low pressure light didn't go out. I thought it may be the oil gears so I swore for a few minutes and then got to pulling it back apart. When I got the front cover off I opened to pump gears up and they themselves weren't cracked, but I did notice the retaining plate that holds them in was cracked right next to the oil uptake tube and the crack goes through the entire plate (see pictures). The tube itself seemed clear and the screen didn't look clogged upon my inspection.

I have yet to check anything further such as bearings or anything like that, but I thought I'd make a post here to see if anyone had any input. Would the crack in the retaining plate be enough to lose oil pressure under operating conditions? And possibly more importantly, would low oil pressure cause the sound I described? I have new oil pump gears on the way and am calling a local parts yard to try to get a retaining plate. I also plan to run some type of snake through the uptake tube to ensure it's clear and it's not something limiting the flow.

Any wisdom would be appreciated. Once I get a replacement plate and ensure nothing is loose in terms of the timing chain or bolts and no worn bearings I'll throw everything back together and get some actual pressure readings that may help. Would not priming the oil pump before reinstall have anything to do with it? I didn't take the pump apart so I didn't think it'd be necessary. Thanks.