2004 Tahoe. Runs Great, Needs Engine (NMSA)

One of my brother's friends asked me to take a look at his 2003 Tahoe.  He said it had low oil pressure and he drove it over here for me to look at it.  I checked it with a mechanical gauge (after some struggle.  WTF doesn't anyone ship an oil pressure gauge with an M16x1.5 adapter!?  And why on earth do they make it so hard to get to?) and it has approximately zero oil pressure at idle.  If you rev it up, it'll get to about maybe 10psi.  My first troubleshooting step was to overfill the crankcase, jack up the back, and check the pressure.  Still zero, so probably not the pickup tube o-ring.  I cut open the filter and drained out the extra few quarts of oil.  Glitter and metal shards everywhere.  Without doing more forensics, it's hard to say if driving around with no oil pressure roasted the engine or if the 288k mile engine just wore out and no longer makes oil pressure.  Either way, the 5.3 is done and needs to be rebuilt or replaced.  It'll drive on to a trailer, but I wouldn't drive it any sort of actual distance unless you like long walks on the side of the interstate in the cold.

The owner said he's just going to get rid of it, but I don't know (a) what a fair asking price is or (b) what he's thinking he wants for it.  If you're interested, I'll pass your contact info along.

Where did you ultimately get the M16*1.5 adapter? My parents Tahoe has landed at my house with zero oil pressure. Starting down the diagnostic path now. 

Spearfishin said:

Where did you ultimately get the M16*1.5 adapter? My parents Tahoe has landed at my house with zero oil pressure. Starting down the diagnostic path now. 

He borrowed it from me,  I think I got it from Amazon, but I am pretty sure Summit also sells them.  I have an ICT Billet catalog in front of me, and it looks like they have several of different sizes available.

In reply to eastsideTim :

Thanks. Ended up getting impatient (have a few days off coming up, want to get their truck off my plate to get back to all the other stuff of mine on my plate), bought a cheapy oil pressure tester off Amazon that supposedly includes M16 adapter AND a 90deg quick connect adapter for the a-hole engineered designs that put you working between motor and firewall. We'll see if what it comes with is worth a damn or not.

In reply to Spearfishin :

There's an M16 plug on the block on the driver's side, near the power steering pump, IIRC, that you can use as a test port.  I have a sender for an aftermarket gauge hooked up there.

https://www.youtube.com/watch?v=16h6vIUvvrg&t=175s

This has all the info on the plug (including where to get it) and building a priming setup. 

accordionfolder said:

https://www.youtube.com/watch?v=16h6vIUvvrg&t=175s

This has all the info on the plug (including where to get it) and building a priming setup. 

I actually used the port to do that before installing the sender.  Main difference is I used a drill pump instead of a weed sprayer.

It took a few tries to figure out how to do it, but I found that it was possible to get a regular impact socket back there with a u-joint and some extensions.  I got the manual gauge on there by putting the adapter on first and then turned the whole hose to get it threaded into the adapter.  At one point I tried a 90 degree adapter but it didn't really offer a good path for the hose to route through the intake, firewall, fuel lines, and wiring harness.

My brother's friend wound up selling this over the weekend.  I'm not entirely sure how or to whom, but he told me that he got $2,500 for it.  I can't imagine that he didn't sell it with the "needs engine" caveat, but I didn't want to know so I didn't ask.