No pressure after losing oil.

[Arlie]

My truck has been sitting since losing oil due to oil cooler line failure waiting for me to have time to check it out further. I want to try "bleeding" the oil pressure sender as suggested in response to my earlier post about this (po with GM engineering). I'm hoping the zero oil pressure reading is not real. Likely a long shot I know. I did figure out to disconnect power to the IP for cranking - thanks.

Can anyone tell me where to find the sender? I see something at right rear behind turbo. Looks hard to get at.
Arlie

[catmandoo]

ya know thats one thing i guess i really haven't had a need to look for but on the old 6.2 the oil sender is behind the intake on the drivers side should be under the glow plug controller.clear down in there

[tom.mcinerney]

Arlie, didja drain old oil, fill with fresh, and install new filter?
On my '95 the OPS threads into a 90* fitting screwed into the block(ops parallel to block surface). It's behind the drivers side head, forward of the trans' bell housing. I could email a foto, but yours may be different. You may have a tapped hole in your block forward of passenger side head, couple inches outboard of timing cover. If remove pipe plug, that's oil source for the turbo; it feeds from line feeding psgr bank lifters...more accessible than OPS POS. A clogged filter might drop pressure. There are pressure-regulating and bypassing valves in the block 'under'{actually over} the oil filter. The helm manual describes servicing these components.
I once bought a p/u truck with a rebuilt small block that had an oil leak from a gallery plug. The cam bearings melted and oozed (flowed). The engine would have been fine with all new main/rod/cam bearings, but i trashed it. That was dumb. Just suggesting a little work may be in order, but not a total loss. Go a step at a time...

[Arlie]

Thanks for the advice. I won't be trashing it just yet but see posts from others suggesting when the engine dies because of oil loss its likely beyond repair. A couple things give some hope. It starts, is not knocking (at least not loud) and was driven not much above idle after the leak started.

No I didn't change the filter or drain the oil, I just fixed the bad fitting and put oil back in. Can't think of why a filter change would do anything but I guess it can't hurt.

I see what looks like a sender rear of the driver's head.

I guess a guage hooked up somewhere would tell the story. I see the turbo line ahead of passenger head.

Any ideas of easiest way to verify oil pressure or not would be appreciated. I'm doubtful air trapped at the sender is the problem. Maybe I'll just have it towed to a shop.

Arlie

[tom.mcinerney]

A clogged filter will either drop pressure downstream, or bypass dirty oil. If you'd drained oil immediately after bad event, a lab oil analysis could indicate what components had begun abrading. Find out why low oil pressure--1 no oil 2 clogged filter 3 particles of abraded engine components which made their way past the filter are causing valves[bypass/pressure relief] to stick open. You want clean oil to flush-out/wash-down interior unless want to do complete teardown, boiling out galleries, etc. Good luck.

[Arlie]

I'm going to tow my truck to a mechanic. He doesn't do a lot of diesel work but I know I can trust him and I just don't know anyone in the shops that do a lot of diesel work.

I posted earlier under "PO with GM engineering". Here's the summary. Oil cooler fitting let go, truck driven about 1 mile by wife, mainly idle, quit twice. No oil on dipstick but at least a quart on gravel driveway. Fitting changed, oil replaced, starts OK, no loud knock but no oil pressure with two runs about 20 sec each.

Any suggestions for instructions that I should give to ensure the right approach? I know there are guys on this forum who can say from good experience... be sure to do A, B, and C and if you find D, E, or F do this.

Arlie