max1

iTrader: (12)

that's on f-body's that pump the pan dry*

im running the high volume pump , great pressure .

thunder550

iTrader: (70)

Seen quite a few threads on this, and experienced it twice personally. Was a stuck bypass valve both times.

CashDudeHomie

iTrader: (5)

I went to TSP today and picked up all of the parts I'll need. They were really cool there. They explained how the oil pump works and gave me some tips on changing it out and stuff. They weren't snobby like some shops are because I'm a truck guy. I highly recommend them.

So Thunder, how do I know if the bypass valve was the problem? Do I just unscrew the hex bolt or take the cover off? I've never opened one up so IDK.

Also, do I need to do anything special before installing it? Like dip it in clean oil before I put it on?

What about before the first start up? Should I pull the fuel pump relay and let the starter turn it over for a few seconds before actually firing it up?

Oh yeah, is the pick up tube screen replaceable or will it be ok? Do you know if my 2003 LQ4 will have timing chain damper threaded holes in the block?

Thanks for any help guys.

08k1500_3

iTrader: (2)

I have changed lots of these oil pumps at work, being a GM shop we do not tear into them, just replace the whole assembly

When putting it back together be absolutely positive the pump is sitting flush against the block, do NOT use the bolts to suck the pump tight.

I pour Assembly lube into the new pump before install, use brake clean to clean out the suction tube and pickup screen unless physically damaged then replace.

CashDudeHomie

iTrader: (5)

Thanks for sharing your experience 08k1500. I will make sure it seats properly before putting the bolts in.

I forgot to ask. Is it safe to just drop the front 2wd suspension crossmember so I can get the oil pan down? Or do I need to put the frame rails on jackstands first?

I did it about 2 years ago, but I forgot. Thanks again everyone.

1slow01Z71

iTrader: (36)

Dropping the crossmember is fine. Wouldnt hurt to let it prime for a little while before cranking it off since your priming the entire oil system.

fredkj3

iTrader: (1)

drop the x member... i had to loosen the motor mounts and lift up on the motor a little bit to get the pan out... also buy another O ring.... always use new O ring!!!

man i hope my pump holds up.....

Tootall

iTrader: (79)

Get a new oil filter and fill it to the top with oil

Take the new oil pump and pour some new oil inside of it. It does not have to be full . . . just a little something inside of it

Use the new RED o-ring for the pickup tube . . . reguardless of what it already comes with

pull the relay out of the fuel pump - Crank over the motor 3 times for 10 seconds . . . let it cool for 30 secs and then hit it again.


After all of that, then start the motor

006rcsb

maybe bad gauge cluster? my 04 tahoe did this, i thought aww crap, but it was just a bad cluster.

CashDudeHomie

iTrader: (5)

It is done. The bypass valve was stuck. I didn't see any rust spots or gouges on it, but it would not slide freely in the cylinder. I put an LS6 pump on and seem to get 5 more PSI at idle and driving. I haven't WOT yet.

While I was in there, I modded the camshaft retainer plate to help oil get between it and the sprocket. You can find the mod on other sites or just buy the new version from GM.

I cleaned out the oil pan and found several small pieces of metal. A lot of it was probably casting that came loose. I found a small piece of glass (from the wreck the engine was in before I bought it. I'm surprised I didn't find it before). In the pick up tube screen, I found 2 bugs LOL.

I put an LS2 timing chain on. It's made with about 25% thicker metal.

2 of the water pump bolts were corroded so I cleaned the threads and put new ones.

I bought a 130mm bolt from a hardware store and it made it MUCH easier to R/R the pulley. It was kind of a pain to get the locking pin lined up but I got it on the second try. This was my first pulley R/R since adding it.

So now I'm really sore and my hair is filled with coolant, so I'm going to bed. Thanks everyone for the replies and tips on how to get this done.