Renée96 Posted March 28, 2007 Share Posted March 28, 2007 '96 OBW with 2.2 engine. Engine always runs well, but has slightly noisy lifters, which quiet down at every oil change. Also has a rear main seal leak, so the engine has been run low on oil a couple times... never overheated or got any oil warning lights though (not that that means much). Anyway, I went to start the car today after it had been sitting for a few hours, and immediately noticed a knocking noise that I haven't heard before. It *might* have been there earlier in the day, but the radio was on so I wouldn't have heard it. I've never heard anything like this before though, so at most, it's only made this sound for maybe 30 miles or so. It was somewhat cold out (maybe 30-35F) so I thought I'd drive it down the block and see if the noise got quieter. It definitely got quieter when under load, but was still there. Power felt fine though. I pulled over and let it idle for a couple minutes, and then it seemed to get louder, as the engine warmed up more. I though maybe it had gotten low on oil again, so I pulled the dipstick with it running just to see if there was any oil on it at all (and there was) and I could hear the noise very noticeably louder from through the dipstick tube. With the dipstick in, it is a deeper, solid-sounding thunk/knock, but listening through the dipstick tube it is a bit sharper sounding. I ended up leaving it where it is and got a ride home. I've read a bunch about rod knocks now, and it certainly seems more like that than, say, piston slap. And I know it's not the lifters. I'm going to try and pull the plug wires one by one tomorrow and see what happens, but does anyone have any ideas about this for now? Wouldn't a rod knock get progressively louder, and not just show up all of a sudden one day? Also, wouldn't a rod knock get louder with increasing engine rpm and load? Thanks in advance for any help! Quote Link to comment Share on other sites More sharing options...
Renée96 Posted March 28, 2007 Author Share Posted March 28, 2007 Oh yeah, should also mention that the timing belt was replaced a few thousand miles ago, by a very reputable shop, so I'm inclined to think its not the tensioner or something like that... Quote Link to comment Share on other sites More sharing options...
nipper Posted March 28, 2007 Share Posted March 28, 2007 how many miles on it, we REALLY need to know that to help determine the noise. Remove one spark plug wire at a time with the car running (be careful of the zappy thing, or at least have a freind watch so he can laugh) The noise should change once you disconnect the wire to that cylinder. If it does its rod knock. nipper Quote Link to comment Share on other sites More sharing options...
Tech1967 Posted March 28, 2007 Share Posted March 28, 2007 Or piston slap, it's part of Subarus hoops that we jump through to see if we can replace your pistons for you. The kind and location of the noise will tell what it is. Buy an automotive stethescope and check this link. http://remanufactured.com/Engine_Noise_Diagnosis_101.htm Interesting note, you may also notice a drop in the noise level from a tensioner when you kill a cylinder. I'm obviously too curious to make the best time I could as a flat rate tech when I start playing around like that but it was the first question I had when doing the piston slap diagnoses as directed by the bulletin. Quote Link to comment Share on other sites More sharing options...
Renée96 Posted March 28, 2007 Author Share Posted March 28, 2007 The engine/car has about 150k miles on it. So I started it up this morning and pulled the plug wires one by one... and there was no difference in the sound (other than due to the rpm change). When I first started it, I almost thought the sound was gone, but then after a minute or so it got louder... which wouldn't indicate piston slap, right? Also, it looked like the main pulley off the crank was wobbling a bit, and coincided with the knocking sound. When the engine is revved, the pulley visibly smooths out and so does the sound. I stopped the engine, and pushed and pulled on the pulley, and it seemed very firm and didn't move at all. Is it possible for the whole crank to move axially while the engine is running? I took a short mpeg clip with my camera, does anyone know a good free place to post the video so yalls can hear what it sounds like? Thanks! Quote Link to comment Share on other sites More sharing options...
nipper Posted March 28, 2007 Share Posted March 28, 2007 That explains the loss of oil. The pull came loose and tore the hell out of the front seal. There is probably some crankshaft damage too, where the keyway is. Even if that solved all the problems, I wouldnt trust this engine any longer. nipper Quote Link to comment Share on other sites More sharing options...
Renée96 Posted March 28, 2007 Author Share Posted March 28, 2007 Here's the video clip: Upload at Putfile Click here to watch subie-noise As for the oil loss, I'm pretty sure it's coming from the rear main seal. There doesn't seem to be any oil coming from the front of the engine at all. And, the leak has been there since we got the car, and we've put around 15k on it. If the pulley was loose, wouldn't I feel some play in it if I pulled/pushed on it? Quote Link to comment Share on other sites More sharing options...
Renée96 Posted March 28, 2007 Author Share Posted March 28, 2007 Here's another video. I don't know if the wobble will show or not due to the video quality. I tried to get a few different angles of it... and at the end, I tried to see if it would record the sound louder as heard through the dipstick tube, but I don't think it worked. ANyway, let me know what you think, and thanks again for all the help! Click here to watch subie-wobble-pulley Quote Link to comment Share on other sites More sharing options...
nipper Posted March 28, 2007 Share Posted March 28, 2007 Thats not alot of wobble, but MAN is that a noisey engine. It sounbds like you have more then one Rod knocking there. So what do you mean by the car running low on oil "again" nipper Quote Link to comment Share on other sites More sharing options...
Renée96 Posted March 28, 2007 Author Share Posted March 28, 2007 Ummm... well... the oil should have been checked a little more regularly, but usually it doesn't get below the "low" mark between the normal 3k oil changes. But, on a couple occasions, the lifter noise seemed like it was getting louder than usual, and it turns out the oil wasn't even registering on the dipstick. I know, that's pretty bad, but it happened... Anyway, the first time was probably 10k miles ago, and the most recent time was a couple thousand miles ago. The whole time though, the engine always ran great and almost always gets about 26 mpg. After the recent timing belt change and tuneup, the mechanic reported the engine to be running great, other than the aforementioned oil leak of course. As for the overall noise of the engine, I thought it was pretty quiet other than the strange knock (maybe my camera is really really good?!). When inside the car, you can barely even tell it's running. Thanks again for your help, I really appreciate it. Quote Link to comment Share on other sites More sharing options...
nipper Posted March 28, 2007 Share Posted March 28, 2007 Running low on oil on these engines seems to catch up with you in time. The noise may just be the camera, but that deep noise is very discomforting. nipper Quote Link to comment Share on other sites More sharing options...
Renée96 Posted March 29, 2007 Author Share Posted March 29, 2007 Well I had it towed to a shop today... I'll let you know their prognosis. They're supposed to look at it tomorrow morning. Quote Link to comment Share on other sites More sharing options...
tcspeer Posted March 29, 2007 Share Posted March 29, 2007 I thought it sounded a little like a Alt. pully or power steering pully or some other pully with the whine that was there with the knock. Did you check the little adj. pully on the bar that comes down,I think from the A.C. compresser? Well I had it towed to a shop today... I'll let you know their prognosis. They're supposed to look at it tomorrow morning. Quote Link to comment Share on other sites More sharing options...
ccrinc Posted March 29, 2007 Share Posted March 29, 2007 If you're seeing the front crank pulley wobbling soon after a timing belt change, it wasn't torqued enough. Should be torqued to 125 ft. lbs. The original manuals said 90 lbs. in error. Unfortunately, this results in crank walk, which permanently damages both the crank and the case. The sound you're hearing is the crank beating on the crank journals. Sorry. Emily http://www.ccrengines.com Quote Link to comment Share on other sites More sharing options...
Renée96 Posted March 29, 2007 Author Share Posted March 29, 2007 Emily: Does the pulley work loose, resulting in crank walk? Would I be able to tell if it's loose by yanking on it by hand? tcspeer: Nope, didn't specifically check any of the belts for tightness, unfortunately. I hope this all isn't a result of the timing belt change. The shop we took it to has TONS of experience on Subies (as do many shops around here of course) so I'd be really surprised if he didn't know about the greater torque required on the crank pulley. We'll see what the shop it's at right now says though... Quote Link to comment Share on other sites More sharing options...
SuBrat84 Posted March 29, 2007 Share Posted March 29, 2007 When you try to wobble the crank pulley are you removing your alt and ac belts? Try taking those belts off and running your car for a minute to see how it sounds. I'm afraid Emily sounds like she hit the nail on the head. Good luck. Quote Link to comment Share on other sites More sharing options...
Renée96 Posted March 29, 2007 Author Share Posted March 29, 2007 The shop says it's the vibration damper. They ordered a new one, and it should be here in a couple hours. I just read a whole lot about the vibration dampers, and it sounds like some people have driven with theirs wobbling for thousands of miles, while others have had theirs fall off- mutiple times! Mine was only making the noise for at most 30 miles, but probably more like a 1/4 mile... even with the stereo on, I probably would have heard it if it started making the noise while I was driving earlier in the day. Anyway, I really hope that's all this is. Quote Link to comment Share on other sites More sharing options...
ccrinc Posted March 29, 2007 Share Posted March 29, 2007 The "vibration dampener" IS the front pulley on these engines. With all the other stuff that connects, it would be highly unlikely that you would be able to move it by hand. You can only see the damage by the wobble when it's running. Emily http://www.ccrengines.com Quote Link to comment Share on other sites More sharing options...
nipper Posted March 29, 2007 Share Posted March 29, 2007 Sometimes i hate diagnosing things over the net, I/we can be off by miles. I had one loosen up on me also. I lucked out as it did no damage. No you wondlnt be able to move it by hand unless the drivebelts were off. And even then if you could that would be very bad. Have you had any work done to the front of the engine in the last year? nipper Quote Link to comment Share on other sites More sharing options...
Renée96 Posted March 29, 2007 Author Share Posted March 29, 2007 Sorry for the implied confusion, I said vibe damper rather than crank pulley because that's how the mechanic referred to it, and I had just gotten off the phone with him. And Nipper, I appreciate your internet diagnosis efforts greatly. My main intent was to get some unbiased advice on here so I wouldn't have to take it blindly into a shop to get screwed. Or, so I could see if I could fix it myself if it is something simple. In this case, I definitely could have fixed this myself if I was at home... but being in the next town over with no tools or place to work on it, I'm okay with paying the shop to do the work. Oh, to answer your question, the only work done on the engine recently was the timing belt job, which was a few months and a few thousand miles ago. Thanks again for the help, and I'll post again once the job is done and it's certain that it was the pulley that was the problem. Quote Link to comment Share on other sites More sharing options...
nipper Posted March 29, 2007 Share Posted March 29, 2007 Oh, to answer your question, the only work done on the engine recently was the timing belt job, which was a few months and a few thousand miles ago. Thats what i was wondering. That can be a real bugger to get tight if someone took it off. nipper Quote Link to comment Share on other sites More sharing options...
Renée96 Posted March 30, 2007 Author Share Posted March 30, 2007 So it was definitely the crank pulley/vibration damper. I got it back today and no knocking sounds at all. Quote Link to comment Share on other sites More sharing options...
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