180sxqc Posted January 7, 2012 Share Posted January 7, 2012 I have been reading alot on the subject and I'm out of idea.. Car: Subaru Legacy 2005, 2,5i sedan Problem: I am experiencing a knocking noise on cold start ups. (20F and colder) The noise lasts approximately 1 to 1:30 min. (might take more time when it is really cold outside) It sounds like a diesel engine. It looks like the sound is coming from the front cover. The noise fades away progressively as the engine warms up. Light burnt sent (I don't know if it's related to the noise problem) The engine must be sitting at cold weather for a few hours to start doing the noise again. After stopping by at the dealership the mechanic said it might be a failing belt tensioner... I stopped at autozone and ordered the complete timing set (tensioner and timing belt), we changed it but the noise is still there (sound is less loud but still there) Is there anything else I should be verifying? - crank pulley? - suggestions? This noise makes me hate my car everytime I turn the key during winter Thanks guys, I really appreciate it Jay Link to comment Share on other sites More sharing options...
ouch1011 Posted January 7, 2012 Share Posted January 7, 2012 Since you have an N/A engine, I'd use a 0W20 or 0W30 synthetic oil in the winter. Even 5W30 dino oil gets quite thick when its very cold. And if you have a block heater, I'd recommend using it on cold nights. Engines don't like being sub-freezing. Link to comment Share on other sites More sharing options...
frank_ster Posted January 7, 2012 Share Posted January 7, 2012 its normal for a lot of subarus.. its piston slap some are worse than others, not much you can do about it Now that's thinking out of the boxer! fyi all 05 + legacy's have built in code reader Link to comment Share on other sites More sharing options...
180sxqc Posted January 7, 2012 Author Share Posted January 7, 2012 I am using the block heater every night and just did an oil change with 10w30 synthetic oil I was hoping i could fix this noise.... Link to comment Share on other sites More sharing options...
frank_ster Posted January 7, 2012 Share Posted January 7, 2012 i only know of 1 subaru that doesn't make that noise .. and thats my 2.5i 2005 with 195 000 kms on it my 2.5 gt did it stock. and the 5 other 3rd gen 2.5i legacys make the noise also. Now that's thinking out of the boxer! fyi all 05 + legacy's have built in code reader Link to comment Share on other sites More sharing options...
rob-2 Posted January 7, 2012 Share Posted January 7, 2012 Since you have an N/A engine, I'd use a 0W20 or 0W30 synthetic oil in the winter. Even 5W30 dino oil gets quite thick when its very cold. And if you have a block heater, I'd recommend using it on cold nights. Engines don't like being sub-freezing. 10w30 is good till -4f 5w30 is good till -40f Changing the weight of the oil is not going to resolve noisy head designs. Link to comment Share on other sites More sharing options...
frank_ster Posted January 7, 2012 Share Posted January 7, 2012 noisy head ? Now that's thinking out of the boxer! fyi all 05 + legacy's have built in code reader Link to comment Share on other sites More sharing options...
180sxqc Posted January 8, 2012 Author Share Posted January 8, 2012 I have been reading about a wobbling crank pulley? Do you guys think it could be what's causing the noise Link to comment Share on other sites More sharing options...
AShoe Posted January 8, 2012 Share Posted January 8, 2012 If it was the crank pulley it wouldn't go away. If you think it is the belts or a pulley you can take off both belts and start the engine. (don't run it for long, or drive. you won't have power steering or alternator power). If the noise is gone then it's one of the pulleys. Link to comment Share on other sites More sharing options...
180sxqc Posted January 8, 2012 Author Share Posted January 8, 2012 10w30 is good till -4f 5w30 is good till -40f Changing the weight of the oil is not going to resolve noisy head designs. I just ordered Mobil 1 0W30 and I will do the change asap, wonder if it changes anything, I will keep it updated Link to comment Share on other sites More sharing options...
frank_ster Posted January 8, 2012 Share Posted January 8, 2012 ^ won't help Now that's thinking out of the boxer! fyi all 05 + legacy's have built in code reader Link to comment Share on other sites More sharing options...
rob-2 Posted January 9, 2012 Share Posted January 9, 2012 noisy head ? The head, ie part that has the valves is just noisy by design. It appears once it heats up they get quieter. However on really cold days it's going to sound like a diesel. I just ordered Mobil 1 0W30 and I will do the change asap, wonder if it changes anything, I will keep it updated This is a waste of time. If you experience any difference it will not be because of your oil change. If you want to 'lubricate' our heads you need to get a product from lucus that has a secondary benefit of lubricating the heads. It's not much of an improvement. Link to comment Share on other sites More sharing options...
180sxqc Posted January 9, 2012 Author Share Posted January 9, 2012 I was thinking that by using less thick oil in cold temperature it would allow the timing belt tensioner to bend the timing belt quicker and that would fix the diesel sound Link to comment Share on other sites More sharing options...
AShoe Posted January 9, 2012 Share Posted January 9, 2012 I was thinking that by using less thick oil in cold temperature it would allow the timing belt tensioner to bend the timing belt quicker and that would fix the diesel sound The timing belt tensioner doesn't rely on oil pressure. A 0w-30 won't hurt hurt, but it probably won't help either. Link to comment Share on other sites More sharing options...
frank_ster Posted January 9, 2012 Share Posted January 9, 2012 its most of the noise is actually the pistons ie piston slap. and thicker oil may actually help reduce noise but slightly lower fuel economy, the noise isn't bad its not going to break anything you just got a motor on the loose side of the tolerance range Now that's thinking out of the boxer! fyi all 05 + legacy's have built in code reader Link to comment Share on other sites More sharing options...
rob-2 Posted January 9, 2012 Share Posted January 9, 2012 its most of the noise is actually the pistons ie piston slap. and thicker oil may actually help reduce noise but slightly lower fuel economy, the noise isn't bad its not going to break anything you just got a motor on the loose side of the tolerance range FYI the MPG effect is unnoticable to the average driver. Most folks would improve MPG by being lighter on the throttle. Both our cars run 10w40 and not change in MPG. Link to comment Share on other sites More sharing options...
.blackgt. Posted February 7, 2012 Share Posted February 7, 2012 That mobil 0w30 won't change anything. Ask me how I know. Stick to your normal oil and live with the piston slap is what I've learned. My 98 did it, my gf's 2001 does it. Welcome to the club.. Link to comment Share on other sites More sharing options...
180sxqc Posted February 14, 2012 Author Share Posted February 14, 2012 I have not yet tried changing the oil grade yet, I will do it next winter since the current winter is almost over... Link to comment Share on other sites More sharing options...
Mega Users paintpollz Posted February 20, 2012 Mega Users Share Posted February 20, 2012 my car has been super slappy lately "Remember Danny - Two wrongs don't make a right but three rights make a left." Link to comment Share on other sites More sharing options...
Nuggy Posted February 20, 2012 Share Posted February 20, 2012 I have an 05 lgt ltd and have recently experienced about a 1/2 second of knocking when my car is started. But I only notice it when it is colder outside. Right now cold in Nor-cal is about 40-50*. I read elsewhere online and it said it could be due to oil gunk buildup.? I need to change my oil now too. I drive about 50 mi/day and around Sac I drive hard. Any suggestions on a good oil, I don't mind paying a little more. I've hadmy car about 6 months and want it to last. Once again the temps around here now are 40-60* daily. Thanks guys. Link to comment Share on other sites More sharing options...
frank_ster Posted February 20, 2012 Share Posted February 20, 2012 ^ thats kinda normal. just keep oil fresh its all you can do Now that's thinking out of the boxer! fyi all 05 + legacy's have built in code reader Link to comment Share on other sites More sharing options...
HAMMER DOWN Posted February 20, 2012 Share Posted February 20, 2012 Almost 188k & no piston lap. That makes 2 you know of frank_ster Oil, Amsoil SSO, 0W-30 Mike Mileage:331487 Retired/Sold Link to comment Share on other sites More sharing options...
Mega Users paintpollz Posted February 21, 2012 Mega Users Share Posted February 21, 2012 slappy happy "Remember Danny - Two wrongs don't make a right but three rights make a left." Link to comment Share on other sites More sharing options...
rob-2 Posted February 21, 2012 Share Posted February 21, 2012 I have an 05 lgt ltd and have recently experienced about a 1/2 second of knocking when my car is started. But I only notice it when it is colder outside. Right now cold in Nor-cal is about 40-50*. I read elsewhere online and it said it could be due to oil gunk buildup.? I need to change my oil now too. I drive about 50 mi/day and around Sac I drive hard. Any suggestions on a good oil, I don't mind paying a little more. I've hadmy car about 6 months and want it to last. Once again the temps around here now are 40-60* daily. Thanks guys. Since 40f isn't 'cold' I would suggest it's nothing to be worried about. If you think you've got oil build up somewhere switch to syn oil. In time it will clean away all the old oil build up. Or grab an oil cleaner (deep creep if memory serves me). Though I don't think it's going to make any difference long term. Link to comment Share on other sites More sharing options...
frank_ster Posted February 21, 2012 Share Posted February 21, 2012 Since 40f isn't 'cold' I would suggest it's nothing to be worried about. If you think you've got oil build up somewhere switch to syn oil. In time it will clean away all the old oil build up. Or grab an oil cleaner (deep creep if memory serves me). Though I don't think it's going to make any difference long term. to clean sludge i put 2L of oil and then over fill it with another 8L of diesel fuel. let run for 20 min and then drain and put new oil. the over filling makes lots of splashy splashy and foam witch cleans very nicely. but frequent oil changes will prevent sludge from accumulating Now that's thinking out of the boxer! fyi all 05 + legacy's have built in code reader Link to comment Share on other sites More sharing options...
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