Interesting behavior from 2001 Legacy wagon - lights and noises

[888]

Let me start by saying I know little to nothing about Subarus. I have a lot of experience with other types of cars and engines but the only flat 4's I work on are my air cooled VW's. But I'm ready to learn because I plan on swapping a Subaru engine into a Vanagon one of these days. 

This patient is a 01 Legacy wagon 5MT with 232k on the body and 140k on the engine. I have some O2 sensor related CEL's to sort out. I'll update that thread in a bit but I wanted to run some interesting behavior by the experts on here. 

First off, note that I had this car checked out by a local Subaru guy and I paid what he told me it was worth as it was, which wasn't a lot. 

I have another 02 Legacy wagon that is exactly the same (color and all!), but an automatic so I have something to compare this one to. I also had a 98 Forester some years ago with 198k that had cold start knock. 

I have something more than the usual cold start knock that I am familiar with. It's quite loud and SEEMS to be coming from the timing belt cover on the driver's side area when the car starts and runs at high idle. It's accompanied by serious belt squeal from one of the belts on the front of the engine, I assume the PS belt because when I crank the wheels back and forth, the noise changes. 

If you rev the engine up past 2k, the knock smooths out. If you drive maybe 10 minutes, the belt noise and knock both go away and it runs like a dream.

I sent a video of the car in cold start mode to the Subaru guy and he thought that it might have a failing timing belt tensioner. 

The Subaru guy listened to it after the PO had driven it 20 miles to have it checked out (noises had all quieted down) and he listened to it up and down and did various things to it and it acted normally. He finally starting pulling plug wires to individual cylinders and thought the cylinder nearest the noise had a bad main bearing. I didn't hear the change but I trust his judgement.

The only other experience I have with a bad main was on a big block and there was a pronounced rattle AFTER revving the engine when the oil warmed and thinned out. We found half a delaminated main bearing in the pan when we pulled that one apart, I didn't hear that same rattle after revving on this one when fully warm. 

Let me add this interesting bit, the last time I started the cold started car when it was in high idle mode, I turned the wheel to full lock left and right to see how the PS squeal would react and at full lock both directions, the BRAKE and battery light would come on. Off of full lock, and the lights would go off and stay off. 

When I revved the engine down to normal slow idle, the BRAKE and battery light did not come on at full lock. 

So anyway, thanks for reading this far. 

First, if a timing belt tensioner on a Subaru was failing, would it create enough drag to create belt squeal and the knocking sound when cold and the battery light at full lock as the alternator slowed down? On water cooled VW's such as a TDI, the tensioner usually silently fails and kills the belt and the engine. 

Second, no, I don't know when the last TB service was done. I'm told the engine was changed 40k ago with an engine with 107k miles. TB service on a 2,5 is due at 105k, right? I don't know that it was done, let's assume it wasn't because we don't know that it was. If the engine truly has a bearing problem, I should change the engine instead of change the TB and tensioner. If you guys think a tensioner could cause all this, I'll do the TB and tensioner. 

 

Third, here is the CEL info:  Car had CEL on when I bought it, PO said it needed oxygen sensors but I bought it cheap and factored replacements into the cost. 

Replaced both front and rear 02 sensors with the specified Densos via Rock Auto. 

Cleared the codes twice and the CEL came back on immediately when I started the car. Always 4 codes in this order: P1133 P0141 P0141 P1133. I know what they are, just surprised the new 02 sensors didn't sort them out and I am getting them twice. Anyone seen this before and have a suggestion? 

Would wiring to the rear 02 sensor cause something like this? The harness looks a little funky just prior to the plug. Maybe not having the rear plugged in all of the way? Sure thought I heard a snap of the plug engaging? 

I'm open to suggestions and comments on any of this. I'd like to salvage the car because it is in excellent condition otherwise (and I like the color, which seems rare for a 5 speed wagon around here at least.  Thanks

Edited December 7, 2014 by 888

[mikaleda]

A bearing knock would be highly unusual, but I guess it could be possible. But it sounds like an multiple things are an issue here. First the timing belt should be inspected, it could have a bad tensioner and/or idler causing a knocking noise. As for the lights, I would bet it's the slipping power steering belt. since the alternator runs off the PS belt and when it was slipping it caused the alternator to slow down enough to turn the lights on.

[1 Lucky Texan]

PS system may be pulling in air - several threads about that.

 

The car can be run minus the TB covers, might be worth checking foe excessive belt movement and looking at the inside surface of the covers for a place the belt is hitting.

 

Also, the 2 piece crank pulley might be separated from its rubber. Look for excessive wobbling/run-out and maybe use a Sharpie or some paint to mark a line across its front - run car, see if the line separates.

[Fairtax4me]

You could have a failed harmonic balancer (crankshaft pulley) or the bolt that holds the pulley to the crankshaft has loosened.

 

If you look at the crankshaft pulley you'll notice it has two sections separated by a rubber layer in between. Its common for the rubble layer to degrade and allow the outer section of the pulley to slip. This causes noise, vibration, and since the outer part drives the accessory belts, the accessories will stop turning or will not turn as quickly as they're supposed to.

 

This is usually visible with the engine running. Look for the pulley to wobble badly.

To check for slip of the outer section, grab some white-out or a paint pen, make a mark across both sections of the pulley. Start the engine and let it run for a few seconds to let it do its shake and squeak thing, then shut it off. Check to see if the paint mark has separated.

 

Another common issue is the center bolt the holds the pulley can loosen. Typically this happens not long after someone has replaced the timing belt and components. Sometimes it can be 10-15k miles later, but usually it's fairly soon, 500-1,000 miles. This is generally due to insufficient tightening of the bolt. This allows the whole pulley to loosen on the crankshaft, and start to spin on the crankshaft snout, and wobble badly. But this doesn't usually go away after the engine warms up. It will keep wobbling for as long as the engine is running.

 

Check for separation of the pulley, that's more likely to fade away after warming up due to expansion of the pulley and the rubber getting hot.

[888]

I wanted to update this in case someone did a search later.  I found a video on the web that duplicated the noise and decided it was most likely that the timing belt tensioner was making the noise.  On any other car I would have thought death by flying parts was imminent but on a Subaru, that noise isn't terminal.  

 

I had a local Subaru guy do a complete timing belt service on it and he verified the tensioner was shot.  Everything I reported other than the CEL's seems to have been addressed by the TB service, and he verified that the TB components were original on the car.  I checked the title and the engine actually has around 125k so I got lucky that everything lasted that long.    

 

I'm still trying to sort out the CEL's.  I've heard it could be a problem with the ECU from when the new engine was swapped in or just an ECU problem in general.  I discovered something interesting when digging into this one, i have a 2001 and a 2002 Legacy wagon - same car, same color, my 2001 is a 5MT and my son's 2002 is an autobox.  

 

I talked to a few Subaru people I know and one mentioned how the 02 sensors changed year to year and I decided to look into that.  I discovered that the 2002 uses a completely different Denso sensor that is common to manual and automatic models (2345003 upstream and 2344132 downstream) versus the 2001. 

 

I decided to see when my 2001 was built and based on the last digits of the VIN I found it was built 189 cars before my 2002.  That’s approximately 9 hours based on production numbers from SIA online. 

 

The VIN code for model year is correct but talking to a friend who worked at Nissan Nashville and GM Moraine Truck assembly, there are big differences between how various companies treat year end runs and changeovers on their assembly lines. 

What I’m wondering is if my “last 9 hour run” of 2001 ended up with the ECU and 02 sensors for a 2002.  The car seems to immediately“reject” both sensors when it starts.  I have a friend who works at the local Subaru place and I emailed the service department there to see if they could be sure what was installed on this car.  

Funny how I ended up with 2 cars so close together when one originally went to Ohio and the other was originally shipped to North Carolina but ended up back in Ohio.   

[brus brother]

Got a little lost in the reading but if I understood correctly, could you swap your son's 2002 sensors into your 2001 come lately? Would they be the same auto to manual if the years were correct? Don't suppose you saved the old sensors? If they were original Subaru installations that could also give you some idea if you are on the right trail.
Hate to suggest opening a can of worms that could end with both cars messed up.