Hey guys this is my first time ever doing any type of form question so help me out. I recently bought a supposed to be 95 Subaru Legacy front wheel drive wagon. Prior to purchase it had the gaskets replaced timing belt spark plugs and wires and water pump. I discovered I had to pass emissions test to title and plate it. So I did the knock sensor Upstream O2 sensor and CV axles. Now for the last week progressively getting worse is a knocking sound from the engine almost like a piston slap when I first start the car and it's still cold. Once it starts to warm up the noise quiets down and within 5 minutes you can't even hear the engine running but it is noticeably loud when it's cold and first starts. Any ideas????

possible timing belt tensioner noise.

 

mechanics stethoscope could help narrow-down the issue. Look for youtube video of subaru tensioner noise.

 

oil analysis with high aluminum would confirm piston slap I think. high iron would be rod knock.

1stSubie95FwdLegacyWagon

First generation subie OB's had the piston slap exactly as you describe, loud at startup, but disappearing almost entirely after warm up. The general train of thought is that it will not hurt the engine or its longevity. My 97 OBW had it starting at about 20 000 kms and five years later when I traded it for another subie it was still going strong with no adverse effects.

2.2's really don't have piston slap due to their relatively large skirts. Sounds like probably lifter noises or possibly timing tensioner. I could tell you exactly if you bring it by the shop. 

GD

So it's supposed to be a 95 Subaru which means it would be Generation 1 yet it has the plug-in ports for the check engine light Diagnostics of the generation 2 or 1996 and newer. I don't know how much of an impact that would have on anything. The person I bought it from I just had the timing belt replaced few weeks before I purchased a vehicle and that did look like the area that he noises coming from was the pulley for the timing belt so I will definitely check into that first. 

Thank you all so much who replied and help me out. And GD what's the information for your shop?

95's do have the OBD-II port and are partially compliant though here in OR the DEQ ignores it anyway. 90 to 94 is first generation, 95 to 99 is second. 

Superior Soobie and Import. Just google us. I'm in the Milwaukie area. 

GD

Edited September 9, 20187 yr by GeneralDisorder

Awesome, thank you for the clarification with the generation dilemma.The guys at AutoZone and O'Reilly's kept telling me it was a generation 1 and its my first Subaru / foreign car so I have no idea but I'm sure glad you guys do. Thanks again.  

I think have this same noise you have described on my 97 2.2.  Thermal expansion of the piston was what I understood for the noise going away after warm up.   Record a video and share. 

Edited September 9, 20187 yr by msmithmmx

Same problem on my 03 OBS. As long as you keep oil in it you should be fine. I just let it warm up a little longer now