markman34 Posted June 29 Share Posted June 29 Hi all. I’m looking at a new to me 2012 forester. 160,000 kms. I’m told it uses no oil and has not had the bottom end oil consumption recall. I’m somewhat familiar with the car as I already have a 2011 that the wife drives. Of course the car has the FB25 NA engine. I’m wondering what an acceptable compression test result would be. I sent my coworker to my trusted Subaru mechanic and the compression test results were listed as 120 psi and “acceptable” There was also mention of the “tube seals” that I’m not familiar with. The car has much less pep than our current 2011 with the same engine/trans. Maybe a compression issue. I did notice lots of blow by but not noticeably more than our current car. Can anyone tell me what an acceptable compression test result would be for this car? I plan on calling the mechanic and quizzing him on the condition of the car. Thanks in advance! Quote Link to comment Share on other sites More sharing options...
89Ru Posted June 29 Share Posted June 29 120 on all cylinders? Downright unusual to have bad rings on all cylinders and no oil consumption. Most if not all subaru's of this vintage will consume 'some' oil. Something is strange. Buyer beware. cylinder compression should be 180-210. Probably oil in the spark plug tube from bad plug seals, easy fix with dealer parts. Anemic performance is consistent with low compression. Blowby isn't a precision thing. Can have blowby and still good cylinder compression. Quote Link to comment Share on other sites More sharing options...
markman34 Posted June 29 Author Share Posted June 29 Thanks 89ru. Does anyone have any documentation that would show what expected compression test values are? i will consult the mechanic come Monday but hoping to wrap my head around it before then. I keep asking the seller for a price but I think he’s waiting for me to bring a number first. Quote Link to comment Share on other sites More sharing options...
89Ru Posted June 29 Share Posted June 29 try this site for factory specs. the numbers I gave you are typical, from legacy outback 2.5 4 cyl 2007-8. my lowest reading is 165, I read at peak after 5-6 cranks. https://sl-i.net/FORUM/showthread.php?18087-Subaru-Factory-Service-Manuals-(FSM)-Every-Model-USDM-EU Quote Link to comment Share on other sites More sharing options...
89Ru Posted June 29 Share Posted June 29 spec for 2007 subie is 142-171 psi, engine warm, fully open throttle. ymmv. I usually check engine cold, just prefer not wrenching on hot engine. Quote Link to comment Share on other sites More sharing options...
nvu Posted June 30 Share Posted June 30 As long as the numbers are consistent across the board, it might just be a low reading compression tester. If the mechanic used a longer/bigger hose, the numbers will be lower. If you're seeing the mechanic, ask if he would test one cylinder of your own subaru. Quote Link to comment Share on other sites More sharing options...
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