Engine compression bears no relation to oil coming out the sensor. That's just a bad sensor. It happens.

Your oil pressure is way to low. Should be minimum 10 PSI at idle, and then an additional 10 PSI per 1000 RPM, up to about 60 PSI or so. (when the bypass valve opens.)

Drop the pan, check your bearings, do NOT run the engine any more, else you may end up just replacing it. (which may not be a bad idea anyway.....)

 

How many miles on the motor and what oil are you using?

 

ok. The oil coming out of the sensor happened to the new one too, the problem didn’t stop when I replaced it.

im looking at the replacement bearings online now and I’m seeing “crankshaft main bearings” and “connecting rod bearings” as different parts. I know we are talking about the connecting rod bearings, but can I replace the crankshaft main bearings without taking out the motor as well?

I’d love to replace the motor haha, I just don’t have that money to drop into the truck, especially for it to not really add much value to it as well.

thanks again

 

odometer says 165,000 and I use 10w-30.
I want to say that the miles are really somewhere around 185,000-200,000 because of the oversized tires causing a slow odometer

thank you

 

Given how low your oil pressure is, gotta be a crap sensor.

You can replace the mains with the engine in place, but, it's an exercise.... less of an exercise than pulling the motor though. Personally, I would be tempted to just yank it anyway, as working on an engine stand is far more comfortable than layin' on your back.

 

I agree with HeyYou on this option. You can find a used 5.9 motor from a salvage yard relatively cheap (especially from a pick & pay style yard) or check out car-part.com for engines in your general area. I swapped out my engine several years ago with a used 5.9 engine from a Dakota I found on Facebook Marketplace since my original engine was rusted beyond recognition since the engine was used in a truck with a snow plow. It made doing any maintenance on that original engine a royal pain.

 

ok thanks. I thought it was a bad sensor too but when I hooked up the mechanical gauge, like I said, it still had almost no oil pressure at all.

 

yeah honestly if these bearings aren’t the problem and it’s a much deeper issue that will warrant a motor pull, I’ll probably just find a different motor as opposed to doing a full rebuild.

thanks again

 

Replacing those main bearings is a time consuming job. I suspect that you will likely have a few rod bearings that are bad as well given that you heard a knock noise at startup. In my humble opinion, it's likely best to find another good used engine. Before doing the swap, I always go ahead and change the timing chain & gearset to a double roller timing chain in addition to changing the water pump and installing deep cup brass freeze plugs. Doing these things while the engine is out of the vehicle make the job easier, especially the freeze plugs at the rear of the engine, which are inaccessible once the engine is bolted to the transmission. As an FYI, the engine block freeze plugs are 1-5/8" diameter and the cylinder head freeze plugs are 1-1/4" diameter.

If you go with a 5.9 engine swap, please be sure to keep your intake manifold, as you will need it if you install a later model used 5.9 engine ('98 and up).