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What now!?!? bad noise FOUND!!! update


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I might have messed this one up good. This timing belt/engine reseal job is just one problem after the next. :banghead: <--- I'm almost ready to do that for real

 

Got it back together and running late last night, with a noise like a bad idler bearing. I removed the belts, still there. Removed timing covers, then started poking around with the stethoscope. Found it most prominent at the mounting bolt for the timing belt tensioner idler. You can literally feel it through the bolt if you put your finger on it. Idler is brand new I say, must be defective, will call the place I bought the kit from in the morning. Went to sleep.

 

Today (rested), decide I better confirm before I go blaming parts. Swapped in the old tensioner idler. No change. So now I have to beleive it is the oil pump, or the water pump. Another round of stethoscoping, just leaves me more confused. Placed directly on the housing of the water pump, the noise is minimal (comparatively speaking). Directly on the housing of the oil pump, it is a bit more noticeable, but still not even half as loud as placing the scope on the mounting bolt for the tension idler.

 

So this leaves me thinking it must be the oil pump. Somewhere along the line, I must have done something wrong.

I did not completely disassemble the pump, maybe I should have. I did check the backing plate screws, and they were all tight.

I did clean the outside surfaces so I would get a good seal (with anaerobic gasket maker). I installed a new crankshaft seal and O ring. Throughly cleaned the block surface before installing. The internals of the pump were never dry though.

I changed the oil filter while I had the engine out, and as usual I filled the filter with fresh oil before installing. When I was ready to fire it up for the first time, I unplugged the igniter module and cranked the engine twice, for about 15 seconds each time, so the pump would not be running dry.

 

So I guess my next move is to remove, disassemble, and inspect the pump for damage.

 

Any thoughts? Ideas?

 

Oh, and to top today off, the water pump gasket blew out on my sedan. :lol: I'm getting good at tearing down the front end of these engines. :cool:

Edited by Fairtax4me
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i have less hands on experience than you do, but i would stick to where the noise is. any chance the mounting bolts for the tensioner or idler are messed up? the mounting bracket isn't cracked? it's hard to imagine that you removed the old and installed the new incorrectly, but if it got cross threaded some how?

 

was it making noise before you replaced the tensioner? did you try the old tensioner again?

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No noise before the work was done. The old tensioner bearing is on now and the noise is the same. The tensioner itself is a brand new Subaru part.

All bolts thread in and out smoothly, nothing crossed, nothing stripped.

 

I can understand how harmonics might cause that part of the bracket to vibrate. The end of the bolt sticks out about 3 inches from the block, so any resonant frequency could be amplified at that area by the lack of surrounding mass.

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I just can't tell. The sound seems to be centered around the area of the water pump, but it doesn't sound like it's coming from the pump bearings. I can hear a very loud whine from the thermostat area of the pump, but not so much up top.

 

It doesn't sound like it's coming from the oil pump either though. Top, bottom, front, the sound is there, but it seems muffled. I tend to think that if it were the rotors of the pump, it would be most prominent directly on the housing of the pump.

 

On the tensioner bearing is where it's the loudest. It's loud in the bracket, and the tip of the tensioner, then fades out as you move away from the bearing. On the bolts for the bracket there's hardly anything.

 

I'm just at a loss here. Think I'm gonna try swapping the old water pump back on first and see if that changes it. Was too busy with other stuff today to mess with it any.

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I just can't tell. The sound seems to be centered around the area of the water pump, but it doesn't sound like it's coming from the pump bearings. I can hear a very loud whine from the thermostat area of the pump, but not so much up top.

 

It doesn't sound like it's coming from the oil pump either though. Top, bottom, front, the sound is there, but it seems muffled. I tend to think that if it were the rotors of the pump, it would be most prominent directly on the housing of the pump.

 

On the tensioner bearing is where it's the loudest. It's loud in the bracket, and the tip of the tensioner, then fades out as you move away from the bearing. On the bolts for the bracket there's hardly anything.

 

I'm just at a loss here. Think I'm gonna try swapping the old water pump back on first and see if that changes it. Was too busy with other stuff today to mess with it any.

Since you mentioned it... any chance a defective t-stat could restrict flow causing eddying/noise?

Edited by brus brother
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Haven't done much with it, but I did grab a used oil pump today. I figure for $7.00, it's worth a try. :rolleyes: Just tired of having to re-compress that tensioner. :lol:

 

you should have grabbed a tensioner too. that way you could have one compressed and waiting for the next attempt.

 

my rear view mirror is 20/20. :)

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People over think things.

 

Take the timing belt off and spin the pump by hand using the stethascope. If it is makingnoise you should be able to hear something odd.

 

The waterpump is always replaced with the timing belt at 105K. Do I dare ask if you replaced the seals and resealed the oil pump?

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Take the timing belt off and spin the pump by hand using the stethascope. If it is makingnoise you should be able to hear something odd.

I did that with everything on the front end. Came up empty handed.

 

Anyway. Everything on the front end has been swapped with other/original parts and it's still screaming. It's something internal. Main bearing perhaps, I don't know. Right now I'm just :mad:

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Is it like a tapping noise? You might check with fellow dealer techs to see if theres a tech tips or bulletin on the tensioner bracket. It had a pin that the tensioner presses against that was wrong in some way, and would cause a strange noise on some engines.

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Is it like a tapping noise? You might check with fellow dealer techs to see if theres a tech tips or bulletin on the tensioner bracket. It had a pin that the tensioner presses against that was wrong in some way, and would cause a strange noise on some engines.

 

No it's a groan/whirr at idle, but above ~1500 rpm it turns into major cat fight screaming whine. No knocking... yet.

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Is it possible you didn't get the o ring behind the oil pump seated correctly or it moved when you pressed the pump against the block?

 

Or the screws on the back of the oil pump backed off? I loctite these but shouldn't make any noise unless they have backed off and are up against the crank surface or something bizarre.

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O-ring is fully seated. It stayed in place nicely all on it's own.

I had to use an impact driver to get the back plate screws loose on the original pump. There were some minor markings on the housing side of the pump and a very small groove where the edge of the inner rotor was rubbing against the housing, but I don't think it was anything worth worrying over right away, and I doubt it was making any noticeable noise.

 

Both tensioner bearings were bad.

Old one didn`t like increased tension from new tensioner.

Wouldn't that be nice. If I thought that were the problem I would test them on my sedan. I don't think it's worth the time to find out though. :-\

 

The problem with this main bearing theory is that I've never heard of a main making this kind of noise. I'm used to hearing knocking/rattling noises from a bad main.

 

Suppose this is a clogged/partially clogged pickup tube? Might that starve the pump enough to create cavitation or rippling/ruffling of the oil, yet still allow the oil pressure light to stay off? It doesn't act any different than my sedan when started. The light goes out in less than a second after starting, when warm it is out before I even let go of the key. Everything sounds fine as far as oil pressure is concerned. Nothing knocking, rattling, ticking. Maybe I should dig up my oil pressure gauge and see what it says.

Edited by Fairtax4me
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Engine was taken out for badly leaking separator plate seal. It also got a rear main seal. Rear cam O-ring. Rear cam plug. Complete timing job; Belt, idlers, WP. Removed oil pump, replaced O-ring and front crank seal. Replaced leaking tensioner. Front cam seals. Front cam O-ring.

Back together, back in the car, cranked with no spark for about 30 seconds to build oil pressure. Reconnected ignitor module, and fired right up. The noise was immediate upon starting.

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'Tis truly a puzzlement. You've done all the right things to make for a happy engine. Frustrating! :-\

 

I can only hope that you're able to track down the source of the problem . . . and that it's a ridiculously simple fix! :)

 

Good luck.

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I have to be careful because U already know more and I don't know shinolas about 2.5 except. bad timing belt or belt out of alignment. Every now and then(not saying on Subies) a belt is smaller on one side. So then it would be the same if a worn cam sprocket was Smaller on one side with a perfect belt. So then there would be a noise where whatever locators tend to rub.

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We may have reached the limit of where we can get to on the net for diagnosing a noise.

 

Lets ignore all the other info for now and go in another direction.

 

The quick and messy way. With the engine warmed up and running, pull one plug wire at a time. Does the sound change pitch. If it does not we will see what we can come up with short of getting a sound recording of it.

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I can get a sound clip tomorrow if you want one.

 

After conferring with a several professional mechanics today, among them one who has worked on Subaru's for at least a decade, the concensus among those more experienced than I, is that there is almost no reason an internal engine bearing (crankshaft/camshaft) would make this type of noise.

The Subaru tech asked about belt tension, and wondered if the tensioner came out any after the pin was pulled. I hadn't paid any attention to this before, but even the brand new tensioner does not extend when the pin is pulled with the new belt installed. It is actually being compressed further when installed in accordance with the procedure outlined in the FSM. I can remove and re-insert the pin into the tensioner with literally no resistance.

 

So in light of the new info I did something I hadn't yet tried... I installed the OLD belt. Throughout all the parts swapping, I had always used the NEW belt. I put the old belt on, old idlers, old tensioner, old water pump still on. Started up... No noise. :eek: New belt with old idlers and tensioner, noise was back.

 

So I tried all the NEW parts again, Idlers, belt, tensioner, everything except the water pump, noise is there and much louder than with all the old idlers.

New idlers with the old belt and old tensioner. Still noisy, but not nearly half as bad.

 

These new idlers have about 1 hour of overall use on them at this point. I don't hear any noise when spun by hand. They are smooth and have resistance like new bearings should, but (this is where it gets interesting) they all have noticeable play when wiggled by hand. :mad: I removed them all to spin them by hand and also noticed one of the smooth faced idlers has a much higher initial resistance than any of the other idlers.

At the same time I found bits of rubber from the new belt smudged all over both of the smooth idlers, and also bits stuck in the teeth of the cogged idler.

 

 

So after nearly a week of diagnosis and parts swapping, I think I finally have a solid theory on this noise. The combination of the belt being too tight, and overall poor quality parts that may now be damaged because of the poor fitment of the belt.

I can't prove that right away since I'll have to wait for the money to buy better quality parts.

 

Oil pressure test results are good. 18-20psi warm idle ~700 rpm. 35-40 psi off idle ~1000 rpm. 70 psi at 3000 rpm.

Seeing good oil pressure has certainly eased my mind of the idea of internal damage. I'm pretty sure now that I can drive the car with the old parts installed and not have to worry about the engine seizing and/or tossing a rod through the block. :cool:

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Interesting. When you say "overall poor quality parts" do you mean the idlers and tensioner? Or the belt? May I ask what kit you used?

 

Anyway, glad you were able to "fix" the problem, hope she runs well for you. At least until you're ready to try again!

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+1, what brand of parts did you use?

where did you get them?

 

did the belt damage the idlers or vice versa?

or was it the combination of bad belt and bad parts?

 

it's probably not worth the time or effort but you could add one new part at a time to isolate which one or two are the problem.

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