Sudden low oil pressure

[kassim503]

I seem to have a little oil pressure bugger thats threatening to detonate my motor if its not addressed cautiously. It all started when I was cruising down to the SS rally @ rausch creek, about a 1.5 hour drive. Drove her hard and fast, had normal oil pressure at the time (cold- 25 idle 55 driving, hot- 10 idle 35 driving) Sounds a little low but its probably from the miles logged on those bearings. Got there and ran it, ran great. After leaving I noticed i was a solid 0-2 psi idle and barely 20 driving, stopped a bunch of times letting it cool and force cooling with water over the oil cooler eventually overfilling it with about a quart, no real improvement. (it was alot of miles on the way back)

Got back and changed the oil, old oil was miserably dirty had a little metal shavings but nothing major. Oil pressure went up, but only by a little (cold- 20 idle and 40 driving, hot 5 idle and 25 driving).

This is where I stand right now, I think, either the mechanical gauge in there is broke, I busted the glass out of it and the needle comes to a true resting point about 5-7 psi below the 0 mark when lifted below the stop pin.

The pickup tube is damaged from the bumps at RC

The pickup tube is clogged from the sudden all day run-a thon that the truck hasnt done in a year or so. Should I attempt to seafoam? ?? it sounds like a bad idea but I really dont want to drop the pan.

The relif valve is stuck open dumping all of my pressure, where is it located?

Lastly, The pump took a dump (highly doubt it)

Also, I was wondering if the pressure port on the filter housing is any different than taking the pressure off the port on the back of the block above the bellhousing, im gonna stick a calibrated gauge on there to test the true extent of this disaster.

Of couse any input is helpful, thanks in advance

 

[kapnklug]

If you noticed metal shavings in the oil when you changed it, theres a good chance you spun a main bearing. Check the pressure again with a different gauge, but I think the only way you're going to diagnose this situation is to drop the pan and have a look at the bearings and the pickup.

 

[1stDeuce]

I'll second that you should NOT be getting metal shavings out with an oil change... Will they stick to a magnet?? I think the bearing material is copper/tin. No sticky... Pump metal would be iron, and it'll stick. I doubt you stuck a relief valve. Double check your gage... if the stop peg is at zero, it should want to rest at about that with no pressure... If it's wanting to go below that, you might have darnaged it when the glass broke, presumably on the RC trip.
C

 

[4bogginchevys]

I have seen a few put transmission fluid in the engine oil to help clean the crap that can aquire with minimal use and/or a lot of miles on old oil. It works great and if your engine really is on it's way out than you wont do any harm that isn't already done. just a quart of trans fuid will get it done, and an hour idling in the driveway with a short drive or two. With little load on the engine it's a safe method of cleaning, i've done it on a small block chevy that sat for 5 years with the oil in it, ran it for a couple hours with the old oil (get it home) and gave it tranny fluid with fresh oil, an hour later I drained out thin pudding....the truck ran great after that, and the engine had almost 200,000.good luck

 

[Hal O'Peridol]

Metal shavings of any kind in oil IS a big deal. Pull the pan, or you will likely be pulling the engine.

 

[4bogginchevys]

shavings, as long as thier very small, are very common.....ever cut open your used oil filter??

Edit: most newer chevys have a magnet on the drain plug, i've changed oil on hundreds of chevy's and 99.9% of them had shavings on the magnet at every oil change.

 

[kassim503]

I'll throw in a qt of ATF on my way over to the lift I'm borrowing tommorow, hope the brgs are still good

 

[kassim503]

AW jeez, couldnt get the lift, but after fighting the truck all day, made 0 progress.

Pan off, pan was clean, pickup had 2 rtv slugs in it that look like it was forced out of a bolt hole at some time. Pump showed little signs of wear. Things that surprised me that there was no gaskets associated to where the pump mates with the block, so a very thin layer of rtv was put down. Also the pressure relif valve seemed a little loose, but the spring was intact and that would cause a low but steady oil pressure problem. Unfortunatley there wehre no 6.2 oil pumps in stock locally, so I just sanded down the end cap a little, taking out all end slack in the gears. Oil is confirmed to pump through teh setup, it blows my finger out of the outlet with ease and if I really crank it down it stalls the cheapie cordless drill pretty well.

The good side of all those hours wasted on getting my hair greasy is that the Rear main seal got replacedIT (, the main and rod bearings look good with a clean pattern, and the cam lobes look unmolested.

So right now I am pointing to a bad gauge, which is becoming more and more evident (it used to stick really bad, and now it dosent stick at all)

Things that kinda scare me, Im missing a support from the engine mount to bellhousing cover, does it matter much? (I feel like sombody has taken the pan off prior), Also, what is the oil pump's one mounting bolt supposed to be torqued down to? I used a breaker bar to pull it off and didnt quite wail on it as much putting it back in.