Cobrae Posted February 7, 2016 Share Posted February 7, 2016 I know topics like this are everywhere and I looked through a ton but none seemed to help. I have a 2002 Legacy GT 2.5L 5sp with 255k miles and last week I was going through the MCds in town and I started hearing a bit of a rapping. I figured it was just the exhaust shields as someone used hose clamps to hold them on before I got it and they tend to be noisy then my oil light started coming on and going off very dim with the beat of the motor so I calmly drove it home no playing but before I got home it was full on knocking but the light never came back. I can go out right now start it up and no knock I checked it over nothing so I took it for another short drive and it didn't knock at all then the next day it knocked again. Today I went out and checked the oil no flakes in the oil. I pulled each plug wire to see if taking strain off a cyl would quiet it or stop it... Nope still there. Pulled the timing cover off on the drivers side and the belt looks pretty new and is tight with no wobble when running. The only thing I haven't tried is running premium in it as I have been running 87 but it sounds way too loud to be that but I'm no expert. I do have a video of it. Only knocks when it gets to temp if its cold it sounds perfectly fine. Makes me think its a rod knock but I have no clue. I'm pulling the motor out of my other Subie right now I just would rather not do an engine swap in my driveway in 2ft of snow. Link to comment Share on other sites More sharing options...
matt167 Posted February 7, 2016 Share Posted February 7, 2016 Rod knock. clearences expand when it's up to temp.. You had enough clearance for it to light the oil light which is less than 5 PSI IIRC... If you wanna try running it still. Baby it and switch to 15W40 oil and run it till the rod wants out Link to comment Share on other sites More sharing options...
Cobrae Posted February 7, 2016 Author Share Posted February 7, 2016 If its a rod knock like I thought Ill just swap motors. Other one just needs to be unbolted from the tranny Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 7, 2016 Share Posted February 7, 2016 Oil light comes on, its beyond too late. Pressure switch threshold is only 3psi on these. Was the engine run low on oil or overheated at some point? 1 Link to comment Share on other sites More sharing options...
Cobrae Posted February 7, 2016 Author Share Posted February 7, 2016 (edited) I don't know. Not by me I just got it on the road I only have around 500-600 miles on it maybe 1000 but I don't drive much. Did an oil change, new plugs, coolant all that when I got it. Only thing that took it off the road for a bit was the o2 sensors. Edited February 7, 2016 by Cobrae Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 7, 2016 Share Posted February 7, 2016 You never know what happened in the care of its previous owner. Everyone loves to say "I've never had any problems with it!" But "problem" is a relative term. Maybe they could have just been unattentive, and there was a problem they never noticed. (Happens quite often) Bad o2 sensor makes it run rich, the old oil could have been heavily fuel diluted for months. Unfortunate for you, (that's $20 worth of oil down the drain!). Good thing you've got a spare engine around! Link to comment Share on other sites More sharing options...
Rooster2 Posted February 7, 2016 Share Posted February 7, 2016 It is an old trick using a heavier grade of oil when you have a rod knock. Instead of changing out your fresh oil change, you can get a thicker oil by adding something like Motor Honey, or other additives to your existing oil. Oil thickner products are sold at auto parts stores and even Wal-Mart. Not worth IMO trying to save a motor with 255K miles on the odo with a rebuild. The thicker oil will buy you some time hopefully until the weather breaks into Spring to do that motor swap you have in mind. Running higher test gasoline above 87 won't help your rod knock problem. Link to comment Share on other sites More sharing options...
Cobrae Posted February 8, 2016 Author Share Posted February 8, 2016 Funny thing is I bought the other car first the GT was the parts car... Gt ended up being in better shape body wise and road legal vs having to do a clutch + a ton of body work and stuff. Other motor has 194k on it but has a new timing belt setup and was actually maintained well. Still high miles but its what I got. Gonna save up for a motor off one of those JDM shops, doesn't seem like a bad deal 1k area for an EJ20 turbo or even $800 for an SVX motor. Wish I could get a good 390 for my Galaxie that cheap lol Link to comment Share on other sites More sharing options...
Bushwick Posted February 9, 2016 Share Posted February 9, 2016 (edited) When I got my 95', I knew absolutely nothing about Subaru. Just wanted an AWD winter vehicle to pull my other car out of winter duty. Being somewhat paranoid due to the mileage (177k IIRC at the time), I pulled the oil pump apart and inspected it when putting a new timing belt on. And as Fairtax mentioned about the really low psi threshold of the dummy light sensor (ironically, I think he mentioned it in my thread as well when 1st doing all this), I opted to to remove that sensor and install a mechanical oil gauge instead. Big part of doing this, is you can keep a closer eye on what's going on with the oil. In my case, was also concerned that if I screwed up the oil pump tear down, hopefully I'd catch any issues before point of no return. Also, this is a great way to get accustomed to what's normal for the engine and what's not. With 10w 30 synthetic, it's usually 75-80 psi cold idle, then 8-10 psi warm idle. Usually 35-40 psi cruising at lower rpm. So if any of those figure drop significantly, I'll hopefully catch it. Safest oil gauges are the ones with the electronic sender that threads into the engine, as you just need to run the wiring into the car, but those are more expensive. More affordable gauges you need to run a tiny hose into the cabin, and it needs to then thread into the gauge, making it more cumbersome to physically mount the gauge, and any leaks will be rapid and messy. I opted for copper tubing (never use nylon as that hardens and cracks with age) and bought an equal length of rubber vacuum hose, roughly 5/16" ID and fed the copper through that to act as insulation, and to minimize and possible ruptures to limit where that oil can physically go. Plus, it prevents kinking the hose with sharp bends. Removed the ash tray and installed gauge there. While saving $40 might not be worth it to some to risk running a mechanical gauge, the copper tubing is safer, plus you get a true reading at the gauge. Definitely worth the piece of mind knowing oil pressure is OK by just glancing down at it. You could try running a straight 30 or even 40 weight like the big semi truck diesels run, and it might buy you some time, but you REALLY need to baby the engine and keep rpms as low as possible at all times to maximize life. That can hopefully get you to work for a short while. When you install the donor, run synthetic oil, and I suggest running a 10w 30. Synthetic is just better than conventional and well worth the few dollars expense. 10w can be a tad thick in cold temps, and some swear by 5w in other cars, but every time someone is on here saying they are getting a loud knocking noise, it's their hydraulic timing belt tensioner and they just switched to a 5w. 10 (winter) is tolerable enough, and it'll thicken to 30 once warm. 10w 40 is a little much, and more suited to desert temps or track racing. Edited February 9, 2016 by Bushwick Link to comment Share on other sites More sharing options...
Cobrae Posted February 9, 2016 Author Share Posted February 9, 2016 This was my first Subie as well. I got it to drive the winter and put my 62 Gal away so I don't ruin it. The donor motor actually has fresh oil in it but I'm going to change it anyways. Local shop recommended 5w20 oil and 5qts.. Yeah I shoulda looked online first lol. Thankfully the motor hasn't been run other than moving the car in the driveway. I plan on putting a gauge in I hate dummy lights, just trying to find a gauge/pod that doesn't look too rice in the car. Not a fan of pillar pods really. Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 9, 2016 Share Posted February 9, 2016 What year is your other engine? Anything up to 2009 needs to run 5w-30. 5-20 is too thin at operating temp, even for cold climate. Link to comment Share on other sites More sharing options...
Cobrae Posted February 9, 2016 Author Share Posted February 9, 2016 Its a 2003, I was running it in the 02 GT also and could be why its knocking. Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now