Over the past two or three days my car has developed a horrendous knocking noise, similar to this video(

) except that has the H-4 engine in it. I checked the oil it is at the right level, the noise does not seem to be coming from the pulleys it seems to be further back. The noise is the loudest when starting the car. She has about 140,000 miles on her, I know the car can develop a small knocking noise when not using an OEM oil filter, so I have an OEM filter on the way to put in it and see if that helps. Anything else anyone can think of would be a world of help, I am hoping this doesn't need to turn into an engine rebuild.

Is this an automatic ?   Could it be the bolts coming loose on the torque converter?

Yes, it is an automatic, and I did infact have the transmission rebuilt a year ago at the end of the month. Could it possibly be related? And It looks like I am still within my warranty, so if it is I need to take it in soon.

Edited April 4, 201510 yr by Xadamx1

Sure sounds like a rod knock to me.  Does it go away at all?  Respond to rpms higher or lower?

It does respond, but it does not go away. It just becomes more or less frequent, seemingly matching the RPM's. It does sound like it getsa little quieter at higher RPMs but it is loudest at start.

I just listened to it again and If it is a rod ....it won't hold together much longer. If it is the torque converter bolts , your flex plate will be torn up by now . Easy enough to inspect the converter bolts. If they are loose you'll know quickly by looking in the inspection hole on the top pass side of the bell housing.  If you find loose bolts and egg shaped holes pull the motor and replace the flex plate.  If the bolts are tight .....then good chance  it could be the engine bearings  and you're looking at much more $ . If it really sounds that bad, I would not drive it at all (or very little, preferably straight to the shop) until you can figure this out. One way or the other sounds like your motor will be hanging off the hook soon. 

At this point the only place I'm driving it to is the shop. It doesn't sound too bad but its not good. I'll take it to a mechanic on Monday and see what they say. Hopefully its under the tranny warranty. And it isn't a rod knock. I haven't been getting any codes but it could still be a rod knock, I hope not. That would probably cost more to fix then the car is worth.

You won't get codes from a rod knock.  That is mechanical in nature.  Codes only come from electronic devices on cars.  You could get to the point where the rod is  about to come out the top of the block, but if nothing electronic is involved, no codes, no blinkly lights.

Well I was hoping for something else. I was on my way to the dealer to get it looked at and possibly a new engine, and the knocking knoise turned into a horrifying grinding noise. So I'm pretty sure she's toast. Now the question I have for you fellas is the 3.6 available for a straight swap into the car instead of a 3.0 or would I even want to do that?

The EZ36 may be the better engine (runs on regular, not premium), but I doubt it will be a direct swap.  Even the EZ30 had 3 iterations.  For instance, the placement of the oil pump is completely different, you'd need the EZ36 intake manifold and all that entails. 

Either way, I don't think you're going to get off cheap on this one.

 

Emily

If it were me, I would check wrecking yards for a good used motor. I have bought two used motors from yards in the past, both turned out to be great motors.  www.car-part.com is a good place to start.

Edited April 8, 201510 yr by Rooster2

In the Mid-west area, looks like a decent, ~100-125K mile motor will set you back ~$1000. If you can grab one from an LKQ yard, they are the best bang for the buck, usually carry a 1 yr warranty and are VERY easy to deal with if you have any problems (such as bad from the yard, shipping damage, requires more repair before use, ect)

 

EDIT: I do not work for or are associated with LKQ, but I use them on a very regular basis. 

Edited April 8, 201510 yr by 86 Wonder Wedge

probably unnecessary now but, an oil analysis (Polaris, Blackstone labs, etc.) would find the bearing metals if an internal part is failing.

Trust me, you don't need a lab report to find those metals.  Just take off the oil filter: it'll be very obvious!

Was this motor ever run out of oil, or near out of oil at any time? If so, this could have caused the trouble. Unusual for any Subie to develop a rod knock, unless run low on oil.

A rod knock will not usually turn into a grinding noise.   Check the idler pulleys and belt tensioner before you panic.

^^^ yep - also look for separated crank pulley, but, seems unlikely if the sound was actually like that in the video.

A rod knock will not usually turn into a grinding noise.   Check the idler pulleys and belt tensioner before you panic.

The thing is, he already had a rod knock.  Now, it sounds like a rod bearing has spun and taken out the internal idlers and tensioners as well which was bound to happen.

 

The idlers and tensioners are internal on this engine, which has 2 chains, not a belt.  Just getting to the idlers, etc. entails taking the front of the engine off (114 bolts, IIRC).  They must be taken off in a specific sequence.  We're building one right now...it's not for the faint of heart!

Edited April 9, 201510 yr by ccrinc

Guess I should have been more specific.  I was referring to serpentine belt idlers & tensioner- Might potentially make some nasty noises when the bearings come apart, which they do regularly.  Quick and easy thing to check.  Some people assume the worst when they start hearing funny noises- thus the "don't panic". 

 

Of course if it's not that, It probably is something internal, complicated, and expensive...