PLEASE HELP!! 85 GL 145k LOUD heavy knock with power loss, added oil, better until 3500rpm loud knock returned, how do I test for problem source ? What do I do first? (have exhausted search feature). Has history of TOD used all treatments no luck. Have pulled plugs to check for a rod bearing-no differences. Afraid to drive, might blow engine? desperate-Need car for work

HISTORY-Have tuned, changed oil 3x with all trmts MMO/seafoam/BG 44k, used Mobile1 10w30, no improvement in HLA noise on drivr side. Driving for 500mi with noise, then..driving at 75 loss of power down to 50mph, loud knocking on pass side- found very low on oil, added to full, pulled plug wires 1 at a time..no change so...I started OK- much improved. Drove 1mi at 3500rpm loud knocking/power loss returned. Now what?????

get a cheap oil pressure gauge and see what your oil pressure is. from your description sounds like you may have spun or destroyed a bearing or two.

Can you take a long screwdriver and use it like a stethescope to hear where the noise is in the engine.

How does the enigne idle.. does it idle rough? is it burning oil?

Hi - idles fine, does not burn oil, good gas mileage...what about bearing check (pulling each wire) is that not the right test? The dash guage is working, the pressure is low about 25. I can check with long screw driver where are the best spots to listen? Will try to get a oil pressure gauge, and am trying to locate the reseal kit for the oil pump, and the front cam seal (o-ring). Thanks for the reply. Anything else I can do?

A good check for a destroyed bearing is to drain the oil. If the oil has a metallic sheen on the top, there's a lot of metal in the oil, and it's almost always from a bearing.

 

-=Russ=-

you can pull a wire one at a time to try to see if the problem is located to specifically one part of the engine, and there are some other indications it can give you(but I dont know all of them). sounds like you've searched quite a bit, I would suggest maybe removing all the spare plugs, putting just a LITTLE bit of brake fluid in each cylinder, crank it a couple times(w/out plugs), add some more and just repeat a few times... and then put just a little more in, add some starter fluid and put the plugs back in and start it up... if there is any crap on the valves causing them to stick it should blow most of it away. I dont know how well this works yet but I'm about to try it on my engine and I will get back to you with how well this works.

Thanks russ... that is something that I can do today. I have heard about checking the oil for metal BUT no one has said exactly how to find metal in black liquid ... :-) until YOU!!

Sound a little scary but willing to try anything THANKS!

listen to russ before you listen to me ... if theres metal in the oil, ... what he said. anotherway to check is grab a strong magnet and see what it picks up out of the oil... most metal that comes out in the oil is going to be kinda powdery or really small flakes, not usually ever gonna get chunks of it or anything

great suggestion thanks scrap!