That oil pressure is ok, not great but ok. If you haven't already switch to at least 15w40 oil. Assuming you are in the northern hemisphere we have colder temps now, pull the thermostat completely and drive around in the truck, see if it ticks at idle. During cooler weather a D2 will only make it up to about 140-160 with no thermostat, if it goes higher than that you have a fan or radiator problem. You can also run a test from a cold start and determine the exact temperature when it starts ticking, if it is above 190 you have a shot at correcting it with an inline thermostat (no shot with factory). If it starts in the 180 range your only shot is a low temp inline and even the only if you live in a cooler climate. If it is an 03 or newer it will throw a low temp code with a 160 or 170 in it.

Oil pressure is probably not your issue, but the no thermostat test should confirm it. After 20 mins of driving the oil temperature will be up to equilibrium with the coolant temp and viscosity will most stop decreasing (not completely, but mostly). If it still ticks with no thermostat it could be low oil pressure in the top end due to a walked cam bearing or some other top end oiling issue. I had a truck once with a walked cam bearing, it bled top end oil pressure enough the lifters would tick at operating temp. You can see a walked cam bearing with the oil pan off from the bottom.

Good luck.

 

Quality was definitely not job #1 at LR in the early 2000 era if these engines never made it to 100K before the bearings went. If I put a new front cover and oil pump on and clean the oil pump pickup tube
and put a new o-ring on the pickup tube, that should help increase the pressure assuming it is a low pressure thing when the oil is up to temp.

I highly doubt I'd be able to see/determine the cam bearing looking up under the truck. This is probably a job best done by someone who has done this many times ie: BTDT. I have a local mechanic
who I can get and trust.

When I took the oil pressure, I had one of the oil cooler plugs drilled and taped for inserting an oil pressure hose in. When I did the test (early 2023), I started the truck and ran it in the driveway as
the hose was dangling underneath. Not an optimal test. but I did get it up to temp according to the in-dash guage.

I'm just getting over a flu so things are not happening yet. If the hayden fan clutch and dorman fan kicks in at 170 (which the guy from the company says it should), I'm hoping I hear the roar
when it starts to cool the engine down when at temp.

btw. I'm in Largo FL (where the truck is). it's is 28/29 most days here (high 80's).

 

just out for a run ....29 deg outside temp. got the engine up to operating temp pretty quickly. around 179 deg engine coolant temp. idling when stopped went between that
and 183. I took the front grill off and measured the temps on the A/C condensor...temp was all over the place when I measured from 104 degrees in the hottest part
on the rad down to 95. lots of fins damaged/missing on it. I guess time to replace it. A/C fan on solid. seems the tick starts when the engine coolant temp/oil gets up
north of 183.

 

this is from Hayden tech support on the unit installed:

"The 2991 fan clutch operates by air temperature, not engine temperature it starts to engage at 170 air temperature ,fully engaged at 180 degrees disengagement temperature is 145 air temperature , this is when the air hits the coil spring in the center it will start to work . when you first start it up it will be fully engaged for about 5 minutes due to the fluid settling on one side of the clutch,"I am hoping to hear a roar now when idling indicating it is activating. If not then I'll have to take off the top cover over the radiator and measure the temps on the radiator to see how equal the temperature is distributed across the fins.

 

hayden 2991 fan clutch + dorman 620-112 fan installed. fired it up...outside temp was 30 deg (using dash EXT button). engine at temp....running 174 - 177 for
15 minutes of idling. did not hear any roaring. but the fan clutch doesn't fully engage until 180. will continue to monitor it....and report back with any updates.

 

check this video out on fan clutches and how to set the temp they engage @:

 

run to wallyworld....28 deg outside temp (sunny). truck ran 174 - 177 coolant temp. A/C blowing nice and cold. Did not hear any noticeable noise
from the fan. Likely because it hadn't reached high enough temp. no ticking observed.