Daddydog007

So I have a knock that has me confused and maybe someone out there could help. This developed the other day going to work. I had stopped by my favorite gas station and topped off my tank of 91 premium with ~6 gallons of 98 octane and started my 45 minute freeway ride to the jobsite. All was normal until the first light getting off of the freeway. The light turned green and I started to go through the intersection and half way through it sounded like I ran over a something metal and was dragging it under the car. I pulled over and looked under the car and there was nothing. Stumped, I jumped back in the car and started it back up and heard this awful rattle and knock coming from the engine compartment and figured the transmission had finally failed again. I have had over 11 transmissions replaced between my 02' and this car, so I am all too familiar with the transmission problems. I called AAA and had it towed home. In all of the cases where the transmission has failed, I was never able to drive the car which is not the case here as it will drive in all gears and feels normal. I looked into the noise and thought maybe belt tensioner, but it doesn't sound others I have seen and heard. The other thing I noticed is that the starter stutters when starting and has never done that before. Not sure if the gas or the starter are related to this noise, but wanted to give as much details as possible.

Any help would be appreciated!!

BTW - There are no shavings or metal detected in the oil.
Thanks in advance,

Brian

This is the link to the video -

Iggy

Sounds like a shroud

Skirmich

Damn, I would guess its a messed up bearing...

Karanx7

iTrader: (2)

I think you spun a bearing. It doesn't sound good.

Have you been running without oil or something? I'd give it a quick check.

scarecrowdjinn

I could be talking out of my butt again, but could it be a valve issue? Maybe impacting the top of the piston.
Can you narrow down where the sound is coming from? top of the engine or bottom?
It also sounds like you get the sound while the engine is slowing down after a rev.

Do you have the tools to do a compression test?

Karanx7

iTrader: (2)

That's not valve noise. It sounds like typical engine knock. It's happening after you blip the throttle and the RPM comes down. Is the RPM dipping super low?

Daddydog007

Thanks for all of your replies...

scarecrowdjinn - It is hard to say exactly where it is coming from without a stethoscope, but it sounds like top end in the head more than in the pan. I am hunting for my compression checker, but I have been swamped at work and this week is going to be busy, but I will make time and check it.

Karanx7 - I was 1/2 qt low, and I usually don't let it get anywhere lower than that. I had the same feeling about it being a bearing, but hoped it wasn't. It is exactly as you stated...when getting off the throttle it drops real low like it is going to die and that is when it is most prominent.

I am pretty surprised that this is the issue as it only has 115K. I guess I was hoping it was something else. I am going to do the compression check and try to figure out my next move. I love my TL and I don't think I am ready to give her up yet. My head hurts and I have a long week ahead of me...

Thanks again guys for all your help!

02tl-p

3.5 swap! take the cams from your type s engine put in in the 3.5 and ditch the spacer.

Karanx7

iTrader: (2)

If it is happening because the engine RPM is dropping really low, then it's not the bearings. The engine is healthy, but it just can't maintain an idle. Clean your TB and IACV.

It's like driving a manual car and letting the clutch engage without enough throttle. The engine RPM will bog down and make the same noise you're getting. The knock is a normal function of low RPMs, but the engine RPM dipping is the problem.