TwoXJS

Hey, guys. So, still trying to definitively determine what's making a knocking sound in my 2.5L. I've asked around a bit at engine shops while pricing a rebuild and I've gotten conflicting info....Anything from a normal engine sound, the oil pump skipping gears , all the way to a rod bearing gone. I'll try and describe it the best I can, but I'll also try and get a good video with sound later tonight.

So, here's what happens....Cold start in the morning, everything sounds good. Oil pressure is up around 50-60 and you can VERY faintly hear a little ticking sound. Slowly gets louder as the engine warms up until it's a clear knocking, like someone knocking on a wood table.

After the engine gets up to operating temp, the oil pressure is good while driving (around 40), but then drops just below the first notch on the gauge, so probably around 10-15? I know the minimum is 13psi, so that seems to be getting purty close....

It's a very distinct knocking sound, so much that people have asked if I've got a diesel stuffed under the hood (I wish!) Again, I'm gonna try and get a good video here in a bit, but any ideas to really narrow it down to? I'm still pretty damn sure it's a rod bearing, myself....

DFlintstone

I thought my 4.0 knock was a rod. That was over 12 years and 150K ago. I have yet to see what end play I have at my crank pulley.....

TwoXJS

Did the knock go away if you unplug an injector/spark plug? And I haven't heard of the crank pulley causing issues....What would I check for?

DFlintstone

Not really the pulley it's self. Although they are two piece with rubber that can be seen coming out sometimes). I meant that if mine was crank end-play, there, or the other end might be a place to check for it.

jopez_89

Does the knock ever go away completely? Does it get louder with rpm? If it's only on cold starts and goes away I'd say piston slap. If it's always there then I'd say rod knock. Check your oil pressure manually, look at the gauge and check for any fluctuation of the needle.

TwoXJS

I can't tell if it goes away, or just get drowned out by the engine. It isn't very noticeable on cold starts, just after it starts to warm up. Needle doesn't move around much, but I know the gauge on the cluster isn't known for being reliable....I just noticed today when I went to get a pack of cigarettes, there's now a rattle as soon as it fires.

It was still cold since I hadn't gone anywhere yet and as soon as it actually fired up, there was a rattling sound for about a second. It was a rather quick rattle, too. Not sure what it may have been, but I'll try and get it in the video I'll get soon.