BenKey

iTrader: (1)

I changed my oil yesterday and did an engine flush (Amsoil product), just before the change. When I started the truck back up, my truck did the normal thing, start out low, then come back up on pressure. This time it took too long to come up in pressure and the low oil pressure light came on for an instant, then shut off after pressure starting coming up. After I ran it for a little while at idle, I took it for a test spin and noticed my oil pressure didn't come up as high as it used to. I have a Thunder Racing LS-6 modified oil pump and usually can nearly peg the gauge at WOT. I tried punching it a few times, but the pressure would not come up much past 20.

I started wondering if it may have been the thicker oil that I had put in. I switched over to syn 20W-50 and thought that may have been it. That was the only thing that had changed from my normal, so I thought that must be it. So, I drained about half of it and put in 10W-30, and it did get a little better. This morning I drove it to work, babying it. Pressure stayed a little above 20. During lunch I changed the filter and 6 fresh qts of 10W-30. Not much change in pressure, so I tried to take it a little easy. So, after work I'm coming home and at idle I got the oil pressure low alert and pulled over - gauge had almost bottomed out. I checked for leaks everywhere - nothing. I cranked back up and alert was gone and pressure was up about 20.

I have it home now and am wondering what to do. The only thing I can think of is the engine flush has broken so much stuff free, that maybe my screen is clogged (wherever that is located), or my pump has crapped out on me.

Any suggestions? Has anyone seen this screen? Does anyone have any pics? And lastly, how the hell do you get the pan off with the engine still in? Does it need to come off?

one03sierra

iTrader: (1)

man i would change that filter first. i dont think the pan will come off with the engine in. i dont want to say it but the flush may have set something loose but you dont have many miles yet do you? there wouldnt be to much to break loose i dont think. but hey you never know. good luck man.

bmbutler

That sucks....I would think its the oil pump.
Scary to think I just put in the same one.

I would go to GM and get a new one, replace it and see what happens.
Did the oil pick up tube O-ring maybe get pinched and it finally tore or something from the LS6 pump install? That's weird and I feel for you.....its not a "quick" job to just switch out an oil pump.

bmbutler

I am not sure about the awd trucks, but the pan will come out on 2wd trucks if you just drop the cross brace (4 main bolts hold it in) between the frame rails.

BenKey

iTrader: (1)

I could swap the oil pump in about 2-3 hours. Still have my stock one. I only have 12k on my truck and about 4k on this pump. I have however, changed the cam three times. But, I have changed the oil within 50, or so miles after each time.

LOW2000

If i may...why in gods name are you running 20W-50 in your truck? Unless you are trying to stop some horribly loose rings from eating oil, then I dont see why you would be using that stuff?

Ryan23silverado

iTrader: (1)

I wouldn't think anything come loose from the cleaner with only 12k miles on your truck. I would lean towards your pump just giving out. I have head before of ported pumps not being as reliable as stock pumps (internal engine forum).

2-3hours for changing the oil pump you are a pro

whitt1

I'd check the sending unit and the voltage to the guage,I'd elininate the possibility of a faulty reading guage before I started taking things apart.

zippy

Here is the stuff from the GM manual to check.


If the engine oil pressure is below specifications, inspect the engine for one or more of the following conditions:
Oil pump worn or dirty.
Oil pump-to-engine block bolts loose.
Oil pump screen loose, plugged, or damaged
Oil pump screen O-ring seal missing or damaged
Malfunctioning oil pump pressure regulator valve
Excessive bearing clearance
Cracked, porous, or restricted oil galleries
Oil gallery plugs missing or incorrectly installed.
Broken valve lifters.

the first two things i'd check is the o'ring seal and the pressure regulator valve. we've had a 3,000 mile tahoe in with a pressure regulator valve stuck before. i doubt something really broke loose although it may be the cause. i'd guess it's just a random thing. sounds like the stock pump lasted longer than that fancy thunder racing one. i'd deffinitly be calling them after you get this straightened out.

mwalls54

i guess you and your helper are going to have to get your paws dirty and drop the pan for safe measures.