So the last 3 days there has been a new issue. The first 2 days, my pistons would slap for about 30 seconds, and the oil pressure was high and would rise like it was a throttle gauge instead. After the 30 seconds, the oil pressure would go back to normal and the pistons would stop slapping. Note: I wouldnt drive it or rev it farther then 1800rpm while it was slapping.

Today however, after about a minute or so, I turned it off and wouldnt drive it because the pistons wont stop slapping and the oil pressure wont return to normal. The oil pressure at its lowest will be around 30 at idle, when i slightly touch the throttle, it will hit about 50-60, and go back down when I let off the throttle.

Now I dont believe this to be a permanent piston slap as that usually occurs with only 1 piston typically and doesn't go away or effect oil pressure. This is every single piston slapping and oil pressure not being correct. So Im guessing it has something to do with the oil pump or oil shaft.

So 1. What do you guys believe this problem to be caused by?
2. Where is the part located in my 3.4l motor, and how hard of a job?

 

I would have to hear it to be sure but piston slap doe NOT come and go. It can fade away as the motor heats up and it would have NO effect on oil pressure. Piston slap is worse in the colder weather.

What you described is a spinning bearing. Oil pressure will spike when the bearing moves out of position and blocks the oil flow. Other then that I can not think of anything that could cause a upwards spike in oil pressure. A drop yes, an increase with noise? NO.

 

agree is sounds like a bearing.

 

Make that three!!!
Can't hear it from here, but the symptoms don't sound good.

 

No way to quote costs on internal engine damage. On high miles motors it is almost always cheaper to replace the motor with a Remanufacture engine than to rebuild yours. Used engines are an option but everything your looking at is going to be 18+ years old unless you get lucky and find someone that has replaced a motor then wrecked the car.

 

I've heard of spun bearings and I know what a typical bearing is, but what is this bearing you are talking about specifically for? What does it connect?

 

I believe they are speaking of your main bearing(rod bearings) te half moon pieces that are on the inner cirlce of the rod as it goes around the crank. The allow the rod to move the piston up and down sort-of on a pivot.

 

Again I would need to hear it to be sure but my guess would be a rod bearing. Main bearing normally only knock under load and when the main bearings spin they tend to seize the motor.

We are only as good as you what you type. Here is a quick trick. Stick you head under the car and under the hood. Do it a couple of times where is the noise the loudest? Under the Car it is a Rod bearing under the hood it could be piston slap or a wrist pin. The reason we all agreed it is most likely a bearing is because a bearing is the only thing that will cause the oil pressure to rise.

Someone says oil pressure rises and a noise starts 99% of all mechanics are going to say the same thing. You spun a bearing.

 

Ok, Ill take a video tomorrow and post it up. But no matter how this works, it seems like it wont be good in the end.

 

Sounds like what my 3.8L did when I spun a rod bearing.

Not only that but Piston slap is not that loud to begin with it sounds alot like ticking lifters but gets quieter as the engine warms up. The 3.4 is not known for piston slap, the 3.4's skirts are similar to the LT1's and other SBC engines. The LS1 was the engine known for piston slap until a redesign of the pistons for the 2001 and newer LS1 engines.

Does the sound you hear sound like a tick- tick or like someone is hitting the engine block with a big hammer?

Massey