Thread: Wierd Noise Oil Pressure Drop

Tweet

Originally posted by drg84
Maaaaaaaybe, just maybe, he hasnt seen the scenario. Anything is possible. But as for the 6 and 8 oiling different, No. Especially when you consider most V6s are built based on prior V8 blocks. Unless there is a massive difference between a oil pump for a 6 pulling oil from the crankcase and moving towards the top of the motor and an 8 doing the same thing, Im missing something. As for the motor in question, did anyone suggest doing a running compression test? Seems to me that would tell if it was a rod bearing doing the warping and causing a drop in pressure

. thats the first time ive heard anybody say check the comp. to see if the rods bearings are worn. whats that got to do with oil pres.? the thrust bearing get worn and lets the crankshaft move all over the place, you will loose a lot more oil pressure by the main bearings than the rods if every thing else is the same. when you mash on the gas the crank will move one way or the other and loose a lot of pres. by the main bearings.

Originally posted by drg84
Maaaaaaaybe, just maybe, he hasnt seen the scenario. Anything is possible. But as for the 6 and 8 oiling different, No. Especially when you consider most V6s are built based on prior V8 blocks. Unless there is a massive difference between a oil pump for a 6 pulling oil from the crankcase and moving towards the top of the motor and an 8 doing the same thing, Im missing something. As for the motor in question, did anyone suggest doing a running compression test? Seems to me that would tell if it was a rod bearing doing the warping and causing a drop in pressure

he was talking inline six sp was i

Originally posted by jramshu
This is not helping the guy.

no kidding

Originally posted by lt1s10
i gave him my opimion and it would have over with if you had'nt turned you noise up at my answer. i dont see how you can put this off on me. you sounded like i did about 6 mo ago. it didnt work then and it ant gomma work now.

whatever try helping the guy instead then read the other threads add your opinion and move on

sorry if i offended anyone just trying to help the guy with the problem

Originally posted by csf03716
hows this sound....its known hes got a knock...probly from lack of lube on initial start up......as for the pressure fluctuation...heres my take....his oil screen is so chocked off with sh*t, that it will just barely suck enough at idle to give a reading.....but once he revs up, it won't allow enough oil into the vanes/gears, and its cavitating/starving for fluid and wont register a reading until the suction equalizes with how much the dirty screen will allow into the pump itself!....so the supply can't keep up with the demand .....plan and simple deductive reasoning.......any feed back?...charlie......oh Tech! where are youuuuu?

I think csf03716 gets the cookie on this one... good pressure at idle with low pressure at higher rpm's is a symptom of oil cavitation from a resriction in the inlet side of the pump. Combine that with a probable minor leak in the pickup tube... problem solved.

Now go take the thing apart so we can all find out what happened!!!!

Originally posted by csf03716
thanx "grinder"...can i trade the "cookie" for a cold 30 pack of Coorslite?...

I'll go with that, but I like my beer just like my coffee... dark, bitter, and chewy. I guess I'll bring my own...

what i been saying the whole time up until people started knocking me

Originally posted by big489
he was talking inline six sp was i

it don't make any dif. L6, v8 if the thrust bearing is worn bad enough to allow to much end play in the shaft, when the motor is revved. up the crank shaft moves one way or the other taking up all the slack in the shaft and causing a max. amount of oil pressure drop past the main bearing and when the motor peaks out the shaft will center itself and the pressure will go back up. it may be worse in the L6 motors but it wil do that on all motors. if its idling at 10 lb. and you snap the accelerator the pressure will go down to say 4 lb. before it starts back up to say 25 lbs. you see a motor doing that and you can be sure its main bearings wear.

Originally posted by DennyW
Start your car up. Note pressure. Let it run until warm. Note your pressure. Now, sitting still, raise the idle up to a fast idle, while watching pressure, and noteing any sounds you hear. If you hear a knocking sound then, that would be a rod knock, most likely. Hows the oil pressure? Then, let it idle, put it in gear. Note oil pressure. Now, while holding brake, put a load on the motor, like torqueing it up (power braking), and note the oil pressure. If you hear a thumpping sound, and pressure drops, it's the mains. Last, it you cruise on the highway, while watching oil pressure. If it starts to drop as you gain speed, you most likely have a pickup tube that is clogged. If it comes, and goes on the oil pressure, it's probably sucking air.

this is sound advice