oil pressure drop once warmed up: Updated
 

after about 20-30min of driving, aka when the oil finally gets heat in it. I have oil pressure drop.
starts out cold at 40ish and builds like it should to 60+ and as its driven the OP gets down to 20 and will build to 30 but you can start hearing the top end rattle.

I put a "new" pump on it but who knows.
I do not think it would be the o-ring since it does have pressure till it gets warmed up.

Thought was to replace pump and if that doesnt help then I guess i will have to rebuild, URGH!

Is it a mechanical guage?

Ugh. I hate LS oil pumps.

iron block or aluminum?

its pretty common on the aluminum block motors, seems like most people say its the lifter bores heating/enlarging letting pressure bleed off.

i dont know, all LS motors make noise, if you hear one not making noise worry.....

is it a 6.0 that is stroked?

junkyard 6.0 iron block with mechanical gauge.

Fram oil filter??

What filter and what oil is in it?

This is why I didnt change my worn out timing chain. Gotta pull the pump to get the chain off and I didnt want to chance fooling with it with my bad luck. Maybe I could have made 375 HP if the chain wasn't worn out and retarding the cam 6-8 degrees lol.

Oil is Mobile dino oil and AC filter (I think). New GM pump purchased in Aug. I have original pump. Going to see if its covered under warranty.

URGH

Do you know the mileage on the motor? Could it be possible that the wrong weight oil is being used and the motor is just wore slap out? I have seen similar issues with the use of incorrect oil weight in combination with "loose" bearing tolerances. However, you wouldn't think that would an issue on a stock motor as long as it doesn't have 300k miles.

Unknown mileage from a 2001 Silverado. 5w30 in it.

My 5.3 has perfect oil pressure and it doesent tap at all.

the 6.0 in the 71 is quiet too. Love that thing!

Fixed it for you.

the iron block motors are alot quieter, my quarter million mile 4.8 is silent, but my LS1 chings and changs like every other one (garbage lifters?). oil pressure is a separate issue than noise though.

my first one made some lifter noise so it seemed. when i pulled it apart it had all wiped out cam bearings

Consensus is to put different oil pump on it and see??

Si

Contacting Scoggin D where it was purchased in Aug 2011 to see if they will warranty it, if not I will purchase new one from some place.
Could put the original one in it and see, that would be 'free'.....

You don't know if the pump is the problem but, you want someone to warrant it anyway?

I am open to all suggestions. the only thing I have seen here and other forums is to replace the pump.
I asked if he would send me a new pump (at my cost) and if the new pump fixes the problem will he warranty the faulty pump. Is that not the way i should handle it?
If both pumps have issues then I have an extra pump here with very few miles that can be used later on something else.

Could it be the O-ring? I guess but thought if that was not seated properly it would not build pressure from the get go.

Do I need a different pump than a stock one? LPE posted on LS1tech that hot oil pressure loss might need more volume.

Listening to all ideas and suggestions, not ruling anything out. Worst case is the bearings are trashed and needs to be pulled. that would suk but I knew that buying a junk yard mileage unknown motor. it happens.

All ears!!

Might just be best to drop the pan and pull a main cap or two as well as a couple rod caps and see what ya got.

I hate to say it but the oil pumps either gonna pump or its not. If you are getting hot and losing pressure its probably not the pump but rather the rods and mains. A high volume pump might help but is a band-aid really.

hmm....PITA but better than trashing it i guess. just a few more bolts at this point.
408 time?!!?

Either that or let me feel that 6.0 and you can take my 5.3 lol.

bring it, I can make that 5.3 scream :eek2:

i dont really know you shon but this is how i dealt with the matter. my truck had little to no oil pressure for the first two years it was together. i could drive it to charleston or goose creek to my job and at idle it had 5 lbs or less. cruising was 15 and wot was 25. never really made any noise other then some lifter noise. and in that motor i put in a new pump before we put the motor in. drive it til it blows

I have thought about that, just run it till it goes but I do not want to F up the heads, I got too much in them to mess them up.
LT1 was knocking like hell one night, raced all kinds of cars on the street, drove it an hour back home knocking, crank had a nice 1/8" groove cut in it. LOL

I didn't get the have them send another one at your cost from the earlier post. Seemed to say something else. All good for me.

500 cash final offer shon.

for the wheels?! or the 6.0? LOL

tenfour, that post left out those details, agree!

hot oil pressure most likely isnt the o ring but to verify you can add like 6 more quarts of oil and see if the pressure comes back up.

at this point the oil level will be covering the pump so any leak between the pickup tube and pump would still suck oil. dont run it like this long, get it hot to where the pressure drops then add the oil and see if pressure changes.

put some 20w50 in it and a ton of gas!

Upstate vs LC definition of ton....U guys need alot more than we do :mrgreen:

Damn. :eek2:

Going to use the Summit Bux and get the Melling high pressure pump and measure pick up tube to be sure I get the correct O-ring. might be up and going TH night-LMAO

That pump b/c of this post by LPE:
http://ls1tech.com/forums/8743784-post28.html

:hide: lol

One of the Melling pumps doesn't clear the timing cover when used with a double roller timing chain. I think its the high volume one though

why not try 10-40 first?