dave833 Posted March 30, 2020 Share Posted March 30, 2020 've run out of ideas trying to diagnose an internal engine rattling and scraping noise on my 07 OBW 3.0 EZ30 H6. It sounds like a chain dragging across metal or gravel shaking in a tin can. It's worse when the car is cold, then it mostly goes away as the car warms up and only happens if I'm making a right turn. If the car is cold, stopped, and idling, I can make it go away by lifting/pushing the left side of the engine up a little. Engine has about 150k miles on it-- not exactly sure because it's one of those Japanese replacement engines. I was fairly certain it was timing chain related so I removed the front cover and inspected the chain. I could see no rubbing or excessive wear or play in the chain anywhere or on the guides. I had purchased two new authentic Subaru chain tensioners so I installed those and buttoned everything back up. There was NO change in the noise-- the new tensioners had no effect. I ran the engine without the accessory belt and the noise was still there so I know it's not an external accessory. It's not motion-related, I turned off the engine when it was making the noise with the car in motion and the noise stopped immediately. I drained and replaced the oil with 5w30 synthetic and that had no effect on the noise either. I'm stumped! Link to comment Share on other sites More sharing options...
forester2002s Posted March 30, 2020 Share Posted March 30, 2020 Exhaust Heat-shields loose? Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted March 30, 2020 Share Posted March 30, 2020 any chance you could use a mechanic's stethoscope or even a dowel rod or long screwdriver to the ear to pin-down the location better? my first gut-feelings were serpentine belt idler/tensioner bearings, or possibly cracked flexplate. Link to comment Share on other sites More sharing options...
Rampage Posted March 31, 2020 Share Posted March 31, 2020 The engine was changed --- Are all the bellhousing bolts still tight? Automatic? Torque converter bolts tight? Link to comment Share on other sites More sharing options...
dave833 Posted March 31, 2020 Author Share Posted March 31, 2020 OK well that was easy to diagnose-- the bottom cover over the flexplate/torque converter has come loose and is rattling. As I recall that cover was bent/damaged when the engine was changed and the bolts probably weren't tightened sufficiently. Fixing it is another matter since the bolts are inaccessible behind the crossmember. At least it's nothing serious, just bothersome. 2 Link to comment Share on other sites More sharing options...
idosubaru Posted March 31, 2020 Share Posted March 31, 2020 8 hours ago, dave833 said: OK well that was easy to diagnose-- the bottom cover over the flexplate/torque converter has come loose and is rattling. As I recall that cover was bent/damaged when the engine was changed and the bolts probably weren't tightened sufficiently. Fixing it is another matter since the bolts are inaccessible behind the crossmember. At least it's nothing serious, just bothersome. it's easier to fix than it seems. i've fixed that same scenario before - recent engine/trans work and that access plate is bent/loose. loosen the two lower 14mm engine mount nuts and lift the engine a little bit and see if you can get enough clearance to access the bolt heads without doing the whole radiator hoses, exhaust, etc. maybe drop the front exhaust headers too if you need another inch or so. also 14mm. rust issues being typically far better out there, this actually could be really easy and take less than 15 minutes with a good jack and tools. 1 Link to comment Share on other sites More sharing options...
idosubaru Posted April 1, 2020 Share Posted April 1, 2020 On 3/31/2020 at 6:30 AM, idosubaru said: rust issues being typically far better out there, this actually could be really easy and take less than 15 minutes with a good jack and tools. Then again, with rust, stubborn work area, low selection of tools to access those 10mm hold down bolts, and 12 point sockets to round off the exhaust nuts it might take 4 hours. Lol! make sure it’s not just bent and it can’t be pushed/bent back into position first before doing any work. Link to comment Share on other sites More sharing options...
dave833 Posted April 2, 2020 Author Share Posted April 2, 2020 (edited) 18 hours ago, idosubaru said: Then again, with rust, stubborn work area, low selection of tools to access those 10mm hold down bolts, and 12 point sockets to round off the exhaust nuts it might take 4 hours. Lol! make sure it’s not just bent and it can’t be pushed/bent back into position first before doing any work. Funny you should say that-- because it ended up taking me about 4 hours. I dropped the exhaust, but the exhaust nuts weren't the problem, one of the motor mount nuts was. I ended up rounding it off (with a 6-point impact socket even!) and had to cut it with a dremel and a cutoff wheel. Oh, and then when I went to put everything back together, the motor mount studs were about 1/4" out of alignment with the crossmember holes. It took a lot of jacking, jockeying and prying to get them lined up again. Oh by the way-- did I mention the cover plate WASN'T EVEN ATTACHED TO ANYTHING. It had completely broken off its mounts. I pulled it out and threw it away since that area of the transmission is protected by the crossmember. Obviously if I'd known it wasn't attached I'd have just pulled it out... I guess all's well that ends well! I really hope I don't have to do that again. Ever. Edited April 2, 2020 by dave833 Link to comment Share on other sites More sharing options...
idosubaru Posted April 2, 2020 Share Posted April 2, 2020 4 hours ago, dave833 said: Funny you should say that-- because it ended up taking me about 4 hours. I dropped the exhaust, but the exhaust nuts weren't the problem, one of the motor mount nuts was. I ended up rounding it off (with a 6-point impact socket even!) and had to cut it with a dremel and a cutoff wheel. Oh, and then when I went to put everything back together, the motor mount studs were about 1/4" out of alignment with the crossmember holes. It took a lot of jacking, jockeying and prying to get them lined up again. Oh by the way-- did I mention the cover plate WASN'T EVEN ATTACHED TO ANYTHING. It had completely broken off its mounts. I pulled it out and threw it away since that area of the transmission is protected by the crossmember. Obviously if I'd known it wasn't attached I'd have just pulled it out... I guess all's well that ends well! I really hope I don't have to do that again. Ever. glad you're done, i've seen countless subaru engines without those lower covers, there's no issue. 4 hours, Oh my, i deserve all the eyerolls and cussing you gave me. All while working ***under*** the car makes it 5 times worse. Sockets roll away or get bumped by elbows/knees, under carriage debris falls in eyes...fun fun. I often use a hand socket on engine mount nuts to see if they're going to be nice or not, particularly if there's any angle due to the exhaust being in the way. I've had them start to round and then carefully get them out without fully rounding them off. I've cut/welded/torched many Subaru exhaust nuts, zero engine mount nuts, sorry I didn't give warning. i was wondering if it was really loose or bent, or as you found, not attached, that's why i suggested verifying that before starting anything. Link to comment Share on other sites More sharing options...
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