97 Ram-oil pressure problem

Messages
152
Location
Indiana
A friend asked me to look at his 97 Ram 1500. It has a 318 with 124,000 miles and runs great, but he noticed his hot oil pressure was dangerously low. He had already changed the sending unit, then the oil and filter to no avail. I installed a master guage and confirmed his findings. When fired up cold, it has about 60 pounds of pressure. After a couple of minutes of driving it starts to drop and by the time it hits operating temp, it is about 5 pound at idle and about 10 at a 1500 RPM cruise. If you rev the engine to 2500 in neutral, it will jump up close to 30. The engine sounds fine and there are no ticks, rattles or knocks. I told him the only thing I knew to do was to pull the pan and inspect the oil pump. This truck has had very mild usage, and is well maintained, so it doesn't seem like a canidate for worn out main bearings. The vast majority of my wrenching is on GM products, so I'm not intimately familiar with the quirks of Mopar power. Is there anything obvious I am overlooking? Also, this is a 4X4 and it looks like I can pull the pan without picking up the engine, Does anybody know for sure?
 
Messages
180
Location
mcminnville tn
I've always been told that bare minimun oil pressure was about 10lbs per 1000 so ya I'd look into that ASAP. If the pan can be pulled without much trouble it probably should be. An oil pump is cheap compaired to what could happen.
 
Messages
25,045
Location
ON, Canada eh?
Bearings on these engines are usually good for life, but I have seen the oil pumps fail on occasion. I would check into the pump first. It's not the easiest to change, but can be done without taking the engine out of the truck if jacked/hoisted up from underneath. \:\!
 

Dieselbob

Thread starter
Messages
152
Location
Indiana
Well, I took the oil pan off tonight. I had to remove the two engine to bellhousing braces and the starter to remove the bellhousing inspection plate, but the pan pops right out. Now the problem; When I got the pan out I looked into the bottom of the sump. Along with about a half pint of oil that didn't drain since I had the front of the truck raised up, was LOTS of sparkles and a some shavings that APPEAR to be aluminum. I then inspected the oil pickup, and after getting over the shock at how tiny the inlet screen was (maybe 1/3 the size of a small block Chevy), I found the screen totally fouled with some crud and more of the shavings. I pulled the oil pump off and removed the bottom cover and was actually suprised by how good it looked inside. I saw no scoring or damage that would lead me to suspect a pump failure. So now I don't know what to think. I am going to show the pan and the pump to some of my skilled co-workers and get their opinion, and I may run it past the local machine shop. Since Blackstone is right here in town, I wondered if they could determine the origin of the metal if I took over a sample from the oil left in the pan. I really don't want to open the can of worms of pulling down bearings, but I may not have any choice. The history of this truck and the way it runs and sounds does not give me ANY reason to supect a major engine failure problem, but the metal I found really unerved me. I want to give my friend the right advice and I am really nervous about bolting in a new oil pump and then having this thing toss a rod out the side of the block in a week. Any ideas/suggestions?
 
Messages
25,045
Location
ON, Canada eh?
The oil pump is Cast-Iron in this engine according to my dad, so I would think you have some other engine problem that is causing excess metal in the oil pan and clogging up the pickup and restricting oil to the oil pump. I would take the pickup off and thoroughly clean it and the rest of the bottom end. I would then fill the crankcase with oil and run it for 500-1000K Miles and send in a sample to a lab and see what they find. Could also just have been the oil pickup tube got blocked by something and so the engine experienced some starvation and this caused the metal shavings...
 
Messages
962
Location
San Antonio, Texas
There's really not much aluminum in there that could degrade like that. Could be thrust bearing particles though. I used to work on these things all the time at the dealer in '99. Put a high volume pump in it and throw some 10w-30 in there with a new filter and see what it does. If there's no rod knock or any major vibrations in the bottom end then I doubt a rod or crank bearing is about to go. Also listen to see if there is any excessive valve train or timing chain noise. Chances are that the crud in the pickup was causing the problem. I've seen plenty of the mid 90's rams run forever with no maintenance, but I also so a whole bunch that had major problems just after 50 or 100k even with great maintenance.
 
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