Oil pressure and fuel injector questions

[Fishermanblues]

I have a 1984 Ram 50 with ~117K miles on it. I've noticed recently that my oil pressure seems a bit low. I get 10 to 13 PSI at hot idle depending on the ambient temperature and 25 to 30 psi when cruising at 2k rpm. At startup (which is ~75 F in the morning) I get 50 to 60 PSI at idle and 80 to 100 PSI when cruising at 2k rpm. I am running Rotella T Triple Protection 15W40, and a newish oil filter with between 1k and 2k miles. I haven't been able to find a spec for minimum allowable oil pressure on these. I have read that the balance shaft bearings are the first to go and could be causing the low pressure, and I know some people recommend you delete the balance shafts all together. I'm not even sure if the pressures I'm seeing are a problem because I haven't been able to find a spec for minimum allowable oil pressure. I am also pretty sure my turbo bearings are leaking because the motor does slowly consume oil and the intake manifold past the turbo gets oily. I would think that the leak would have to be much worse to produce the low pressure I'm seeing. I also wonder If there is a problem with the oil cooler circuit not opening at the correct temperature and is allowing the oil to get too hot and reducing viscosity.

On an unrelated note, one of the fuel injectors is leaking at the return line that comes out of the side (see attached picture) it looks like someone tried to solder the joint in the past to stop the leak. The engine manual I have doesn't address the injector return lines at all so before I take it apart and potentially destroy parts that may be irreplaceable I thought I would ask for advice here.

19487

Thanks,
Andrew

[skullzaflare]

http://www.ebay.com/itm/Pajero-Shogun-Sport-L200-4D56-2-5-SPILL-LEAK-OFF-RAIL-PIPE-WITH-4-ALLY-WASHERS-/381510471007?hash=item58d3cbcd5f:g:lXIAAOSwdGFYrGf L&vxp=mtr
Should fit

[Fishermanblues]

Thanks for the suggestion skullzaflare, I went ahead and ordered the leak off rail and it should be here any day now.

A couple of days ago the heater hose connection to the head (visible in the picture in my first post) started leaking a small amount of coolant and when I took it apart I found the hose barb was too corroded to seal to a new hose. So I partially drained the coolant and replaced the elbow and now the engine is running much cooler, it used to run at a pretty steady 190 ever since I got the truck, but now it cruises at 160 and climbs to 165 when stopped. And because it is running cooler my oil pressure is higher, at hot idle I'm seeing 15-18 psi and I'm getting 30-35 psi at 2K rpm. I'm not sure what caused the change but I have some ideas. Maybe the thermostat is stuck open and it's failure just happened to coincide with me fixing the leak, or there is a piece of debris from the corroded elbow jammed in the thermostat holding it open. Or the coolant has always had a bubble in it that I somehow cleared when fixing the leak, but managed not to clear the other times I've drained and refilled the system. Or somehow the old coolant just wasn't doing it's job. What do you guys think it could be?

[pennyman1]

Air might have been getting into the system causing an air bubble in the system. There is a jiggler in the thermostat that is supposed to get the air out of the system, but a bad fitting could let air in when it cools down and seal under pressure.