Noise post cam belt r&r

[RMDAV]

My first post to this forum, apologies for any faux pas...

My '97 Outback 2.5l DOHC 5speed, 105k, is making a Screeching sound since having its schedualed cam belt replacement. Begins at 2500rpm up to 3000, and probably beyond, but drowned out by regular engine whine. By my ear it's coming from the alternator, so I had hoped for a mis-adjusted belt. Took it back to the reputable independent shop (but my first activity with) for a look see. Removed both the alternator and AC belts and started it up; same noise unchanged. He thinks it is a normal condition, I assured him it is not and has only done so since his service. Gave me the shrug-of-the-shoulders answer. So, anyone care to venture a guess? I've not seen inside this part of the motor, so it's just speculation, but since the cam belt tension is hydraulic, auto adjusted, what else might be the cause? Idler gears or some type of belt guide? Hmmm...might just have to drive it 'till sumpthin' stops. Not.

Thanks for any input.

[Fairtax4me]

Could be the water pump, idlers, tensioner, belt rubbing on the cover, many things. Do you have a list of exactly what they replaced?

[hankosolder2]

Without hearing the noise, that sounds like a worrysome problem. If there's a bad idler wheel bearing and it locks up, your timing belt can break, engine jumps time and you're looking at bent valves. Is your mechanic going to cover it if that happens?

 

I'd suggest spending the $ for a second opinion.

 

Nathan

[RMDAV]

Well, just the cam belt was replaced, can't say much about the rest belt assembly. Not seen any diagrams, so I should do some research on the subject. I'm leaning towards the bad bearing theory. Can't accuse the mechanic of any possible cause during the job, since I don't know what it involves. Might there be any potentially flawed procedures anyone knows of? Is there some inspection of the system he might have missed, or anything he should have discovered had he looked?

[rxleone]

Well, just the cam belt was replaced, can't say much about the rest belt assembly. Not seen any diagrams, so I should do some research on the subject. I'm leaning towards the bad bearing theory. Can't accuse the mechanic of any possible cause during the job, since I don't know what it involves. Might there be any potentially flawed procedures anyone knows of? Is there some inspection of the system he might have missed, or anything he should have discovered had he looked?

 

Sounds like bad idlers to me - I would not drive it until someone competent has a look at it. When I did my stint at a parts store it was a classic warranty belt failure symptom on EJs - mainly DOHC EJ20s - bearing noise, seizes, the belt overheats. If you're lucky it melts onto the water pump, tensioners, and idlers, and stops the engine. Worst case scenario it snaps the belt, causing it to nine times out of ten bend your valves. Coming from someone who's had a belt snap and felt the full force of bent valves, I say; it is NOT a fun way to cause valve failure.

 

This would ONLY happen to aftermarket tensioners and idlers. As soon as we pulled the aftermarket parts off the shelf and replaced them with genuine NSK Subaru parts, failures stopped happening. Are your parts genuine?

 

I've also seen in the reports that there is a guide in the later model EJ engines above the crank sprocket to align the belt correctly. This alignment done incorrectly or not at all can also cause the belt to fail. You'd have to talk to a mechanic at a Subaru dealer about that one though, as I've only worked on older EJ engines.

Edited April 22, 2010 by rxleone

[Olnick]

Is there some inspection of the system he might have missed, or anything he should have discovered had he looked?

 

For your viewing pleasure, RMDAV, the picture in this article shows the various idlers the timing belt travels over. All should have been checked carefully by your mechanic buddy when he was in there. (By the way, the pic was apparently flipped left-for-right in publication, but you get the idea.)

 

http://www.motor.com/magazine/pdfs/102001_08.pdf

 

Good luck getting it sorted out.

[Mike104]

For those that like to watch instead of read:

 

http://allwheeldriveauto.com/subaru-repair-seattle-timing-belt-idlers-explained/

 

Here is an EndWrench article about Timing Belt R&R on the 2.5L DOHC engine

 

http://www.endwrench.com/pdf/engine/FtTimingBeltReplaceF00.pdf

 

There are some threads about what else you should change "cause you are in there" when doing a timing belt change.

 

The short version:

 

All Timing Belt Idlers/Tensioner

Camshaft Seals

Front Crankshaft Seal

Water Pump

Thermostat

Reseal Oil Pump

Accesssory Drive Belts

 

The idea is that since most of that stuff either has to be removed to get to the timing belt or is easily accessible once the timing belt is off, preventative maintenance to do it now.

 

Others say inspect and only fix what's bad. I changed just the timing belt and a year later the oil seals went out. Had to pay for timing belt replacement (2nd time) and oil seals. Your call.

Edited April 22, 2010 by Mike104

[Fairtax4me]

Well, just the cam belt was replaced, can't say much about the rest belt assembly.

 

This is why you're going to find a new mechanic. He either doesn't know what he's doing, or knows full well what he's done and is trying to hose you.

[eppoh]

When you took it in for the belt change, did the shop offer or suggest changing the idlers and water pump?

 

My money would be on one of those. Any shop with subie experience should have suggested changing them. But, a competent shop with no subie experience might not have known. Pulling the timing cover and using a mechanics stethoscope with the engine running will likely reveal the source of noise. If it is an idler or water pump, you should change them all while it is apart.

 

One other thought, is the accessory belt idler for the a/c. I have an Impreza 2.2 in my garage right now that had that idler go out and threw the ac belt through the timing cover and knocked the T belt off, crashed all the valves. Here again, a stethoscope can tell you if that is the source.

 

Let us know what you find.

[RMDAV]

Tentatavely set up another go at the problem Monday. They're worried about blame, ultimately a secondary concern, got to find out what it is and fix it... They are a good shop, willing to pull covers and see, also tentavely at no or reduced charge. Don't get any "scam'" alarms. Wondering how a Dealer would have gone about this.

[svxpert]

Wondering how a Dealer would have gone about this.

 

 

well, being the car is 13 years old, granted only 105,000 miles but the age is more important. They would have told you they recommend the following parts be replaced:

 

All Timing Belt Idlers/Tensioner

Camshaft Seals

Front oil Seal

Water Pump

Thermostat

Reseal Oil Pump

Accesssory Drive Belts

 

you didnt tell us how much you paid to have your belt done. This will usually tell us what was done. I used to cam belts on SVX's for $250, that was 5 years ago. No most owners would want those other things replaced too. I didnt hammer them because the engine was opened up at that point and it was easy to do cam, oil seals, oil and water pumps and the accesory belts.

[RMDAV]

Well, the problem has revealed itself. I did an oil & Filter change last night and after running the engine a bit to facilitate topping up the oil, discovered a puddle of coolent beneath the oil pan and a steady drip comming from the area where the coolent hose on the drivers side attaches to the pump. Hose itself is completely dry, but seepage can be seen at the gasket between the hose mount and pump. Question is, does a failing waterpump make this kind of noise (the screech) and this belching of fluid? Is it just coincidence that this failure came at the same time as the cam belt R&R? Might there be anything done during that proceedure that could do in the pump? Care to guess, anyone? I actually feel kinda lucky to have caught this, and relieved that there is something obvious to point a finger at. Next thing is, can I drive this to the shopfor repairs. About 3 miles... what's the risk?

[johnceggleston]

i'm not sure i'd go back to that shop, they did the timing belt and now you have engine noise and a coolant leak. i don't know what they charged for the work, but it was not worth it. and as probably mentioned above this is an interference engine if the water pump or idlers fail you are in for some serious money.

 

find a shop that works on subarus and replace all related parts not just the belt.

[MilesFox]

the water pump will leak behind its pulley when the bearing starts to go. it is designed to leak out of a weep hole when it wears too much to indicate it's due for replacement.

 

any timing belt job should at least include replacing the water pump with it's bid for the work, standard procedre.

 

of the WP fails, there goes the belt, and the valves.