Gnobes Posted March 18, 2020 Share Posted March 18, 2020 Hello, I recently purchased a 2017 Subaru Legacy 2.5i Limited. There is a knock sound whenever the vehicle has been sitting and is completely cold. The motor seems to run somewhat loud but it could just be the cold startup routine. Afterwards, it's pretty quiet. When I say knock sound, I am not referring to detonation/ping. I mean quite simply, it sounds like a "knock" or "thud". It's as if the motor is moving the exhaust or something and it is hitting something. Is this normal for 26k miles? FYI - no noise or issues while driving the car. Vehicle seems to drive just fine. CVT transmission (did the limited even come in manual?) Link to comment Share on other sites More sharing options...
awfulwaffle Posted March 18, 2020 Share Posted March 18, 2020 Make a video and post it. Without hearing the sound, most of us are going to suggest it's piston slap, which is common in Subaru motors. At least on the EJ25, not sure about the FB25 in your car. Link to comment Share on other sites More sharing options...
Gnobes Posted March 18, 2020 Author Share Posted March 18, 2020 (edited) Good point. Be right back. Update: motors still too warm. No knock sound: No knock #2: Edited March 18, 2020 by Gnobes Link to comment Share on other sites More sharing options...
Grnlantern1 Posted March 19, 2020 Share Posted March 19, 2020 Good point. Be right back. Update: motors still too warm. No knock sound: No knock #2: Hopefully its not the Flywheel/Torque converter Explosion like one other person had here on the forum.. How's the oil level when it's cold? Also check under the car and see if your Tranny Pan is Black with oil you might of had the CVT Leak and now it could be seriously failing.. Sent from my SM-G965U using Tapatalk Link to comment Share on other sites More sharing options...
hkshooter Posted March 19, 2020 Share Posted March 19, 2020 I can't hear your engine but both of my wife's 2.5ls have a thud to them when cold started. Noise goes away after a couple minutes. Normal for these it seems. Sent from my SM-G950U using Tapatalk Link to comment Share on other sites More sharing options...
Gnobes Posted March 21, 2020 Author Share Posted March 21, 2020 Ok finally got one with the thud. Very hard to hear but it's there. Link to comment Share on other sites More sharing options...
gathermewool Posted March 23, 2020 Share Posted March 23, 2020 Can’t hear anything. It might help if you left the key in ACC and let the bling bling bling expire before starting. '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
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