Thread: Wierd Noise Oil Pressure Drop

Tweet

I started my car up today and it almost sounded like it was knocking but it real quiet.. the oil pressure started out at 40 leveled at 20 for a while...then when i pressed on my gas it dropped... and when i left off it went back up.when my engine got warm it sounded like my #1 pistion was banging still quiet tho.....im so confused on what the problem is

Is it a nunga nunga sound ? cause if it is get ready to pull your motor, from what you describe, it sounds like the motors run a big end bearing.

Originally posted by YoungMalibu
I started my car up today and it almost sounded like it was knocking but it real quiet.. the oil pressure started out at 40 leveled at 20 for a while...then when i pressed on my gas it dropped... and when i left off it went back up.when my engine got warm it sounded like my #1 pistion was banging still quiet tho.....im so confused on what the problem is

Did you check the oil level ?

I check my oil its good, so if its a bearing, do i need to get my whole engine rebuilt or can i just get it replaced..

Originally posted by YoungMalibu
I check my oil its good, so if its a bearing, do i need to get my whole engine rebuilt or can i just get it replaced..

IF it IS in fact a spun rod or main bearing, the crank will have to be at the very least polished, but most likely reground. If a main spun enough to damage a main journal, you may have to align-bore the block.

Are there metal filings in the oil?

Well, the thud sound it right.. i cut open my oil filter and it is a shiny metalic look with a couple lil pieces of metal.. So what price range am i looking at to get this fixed.. or am i looking at a total rebuild

When I was interning at Dodge dealership we had a few cars and vans comming in doing the EXACT same thing. Start it up, does alright a little knocking, drive down out of the dealership and then it knocks more but not real loud at all and then the oil pressure drops when you apply the throttle more. We took a look at the engines took the heads and all off and oil build up in a few that looked like a few barely ever had an appropriate oil change and we had to just go put in a WHOLE new engine and then the others needed bearings and all or rebuilt. Take the engine apart and see what's wrong with it.
You won't need a whole new engine or nothing of course we only did that because one was a Altel van with the tires all in wire from worn so much and not taken care of so the company brought one over. And I know I am not the one here that gives the info or nothing and I get crap about how I should not say nothing but unless someone dissagrees with me here then I know that could be a possible problem.

I just experienced the same thing with my 327 drag motor. Sounded fine, ran great, but had a slight rattle sound above 2,000 rpm and the oil pressure began to fluctuate.

Turned out I had a main bearing cap break in two and apparently the crank vibrated so violently that the other main caps are egg-shaped and will not hold a bearing shell(nearly 1/8" play between shell and cap!). Hope yours isn't like mine!

Bowedup

anytime you lose oil pressure when you step on the gas and it goes back up your oil pump is catching air low oil level will cause this or pick up tube not installed properly as for the nock its hard to say running low on oil can cause bearing failure or lifter noise

withdrawn

Originally posted by big489
anytime you lose oil pressure when you step on the gas and it goes back up your oil pump is catching air low oil level will cause this or pick up tube not installed properly as for the nock its hard to say running low on oil can cause bearing failure or lifter noise

Well in our case it wasn't our oil pump, it needed a new engine...

Originally posted by FMXhellraiser
Well in our case it wasn't our oil pump, it needed a new engine...

did the oil pressure go up and down or did it go down when you step on gas and go up when you let off two diffrent symtoms two different problems.

Originally posted by big489
did the oil pressure go up and down or did it go down when you step on gas and go up when you let off two diffrent symtoms two different problems.

if its full of oil and every thing is ok then when you step on the gas the pres. goes down and when you let off of it it goes back up thats a sign of a worn main bearing.

Originally posted by lt1s10
if its full of oil and every thing is ok then when you step on the gas the pres. goes down and when you let off of it it goes back up thats a sign of a worn main bearing.

been building engines for 25 years never seen worn mains do that

Sounds like mains to me. The knock might be a lifter, unless it's coming from under the engine. You can replace your main bearings alone, but that is not a good idea. I replaced rod bearings and a couple weeks later the mains starting knocking. I would take it and get an opinion from a mechanic or two. Machine shop here is about $600 to do a long block, if you do the rest yourself.(ex. pull it,strip it, put all back together)
When you find out remember to come back to CHR and let us know what you found.