98 Subaru Legacy Outback timing belt problems



My wife and I bought a used 98 Legacy Outback last year from a local Toyota dealer. Very clean though w/115K mi. on it and no history on the car I had them replace the timing belt as a precaution. They didn’t get it right and it was leaking oil from the cam seals and front cover when they were finished. We took it back and they agreed to take it to the local Subaru dealer who replaced the timing belt. That was in Dec. 2007. Fast forward to Apr. 2008 - knocking noise from front of block prompts us to take it to our local mechanic who removes front cover to find the bolt securing the timing belt tensioner loose, and the inner 1/4" or so of the timing belt shredded. Belt otherwise intact. No other apparent damage without further disassembly which we decide to have done at the Subaru dealer (only one in 100mi) who replaced the belt in Dec. The Subaru service rep disclaims responsibility for the timing belt tensioner being loose, saying the tensioner failed causing the bolt to come loose, but agrees to replace the belt and tensioner and charge us only for the tensioner part, no labor charges. Supposed to get it back today - service mgr. calls to report they finished timing belt replacement to find knocking still present - propose head job on both heads and possible all eight valves - est. from $1,500 to $2K - though they propose to split cost.

Of course we’re not too happy about this , considering the dealer replaced the belt back in Dec. and we’ve put very few miles (wild guess 2-3K) on since then. I’m not a mechanic, but I doubt their story about the tensioner failing and causing the bolt to loosen. Even if that were the case, since they replaced the timing belt in December we feel that if the tensioner were that close to failing they should have recognized it and alerted us.

Anybody out there have enough experience with 98 Subrau Legacy Outbacks to know whether the timing belt tensioner would fail so miserably on it’s own just a few months after a belt replacement? Would a failing timing belt tensioner provide warning noises well withing the timie frame of a few months prior to failure?


I think the tensioner, idler, and cam seals are normally replaced at the 105k miles point. It sounds like the dealer may have messed up. I can understand your disappointment but it may be best to take the offer they made to you. I assume the valves have been now been bent due to the problem. If you do the work needed, you will also have new headgaskets that can also be a problem at times.

Here is a link to a good Subaru site I recommend you should join. There is lots of good help from the folks there on our favorite cars.



It’s possible for a failed tensioner to loosen the belt. The proper recommended procedure is that the tensioners always be replaced with the timing belt; no exceptions.

It’s hard to say about any warning noises. Often any growling or whining may be covered up by other engine noises and it is possible for a tensioner to fail quickly.

JMHO, but I fault whoever replaced the belt without doing the tensioners at the same time. Normally, the water pump is also replaced at this time.


Red flags are FLYING. First of all, you bought a 10-year old car with “no history.”

Then, the Toyota dealer “didn’t get it right.” We’re talking about a timing belt replacement! There is no option other than “get it right.” If the timing belt was installed other than correctly, and the engine was started, damage was inevitable.

Oil leaks have nothing to do with the timing belt. There are (were) probably seals that needed to be replaced while the timing belt was off, but I guess they didn’t replace them. Did the Subaru dealer replace the leaking seals? Your post does not say.

I want to know more about “the inner 1/4” of the timing belt shredded." The timing belt is only about 1/4 inch thick, maybe less. If the timing belt had somehow managed to “shred” 1/4" of its thickness, you’d have nothing left but a large, black, rubber band, which would drive NOTHING. Not the camshafts, not the water pump, NOTHING.

Someone has been less than truthful.

If the tensioner bolt was loose, then the person who initially replaced the timing belt is responsible, not Subaru. I’m amazed that Subaru is even talking to you, considering the age of the car.

Can I possibly hope to recoup some of the money I’ve spent on my '96 Legacy engine?


To expand on what Cougar says (“I assume the valves have now been bent due to the problem.”), I think the “knocking” sound is from the valves which were bent by the timing belt slipping due to the tensioner. The bent valves make it necessary to remove the cylinder heads and replace the bent valves, and do other repairs. I think the dealer should perform ALL the repairs without any further cost to you.
If necessary, you can pursue this in small claims court.


Update - I stopped by the dealer yesterday afternoon and talked to the current acting service manager - their service manager was out of town on training. Told him we were unhappy and felt they should pay for all the repairs.

I asked to see the tensioner so he pulled it, the mounting bracket, and the belt out of a trash can. I confirmed that the tensioner had failed by placing the plunger face down onto a work bench and pushed down on the body of the tensioner. The plunger depressed fully in just a second or two. I found a description last week on the web describing step by step the replacement of a timing belt on an Outback, and that description stated a properly functioning tensioner takes 10-15 minutes to fully depress using body weight. So it does seem more plausible to me now that the tensioner failed. The threads for the tensioner mounting bolt were also worn so that the bolt doesn’t seat securely. The front of the tensioner pully has a sharp ridge worn on it due to rubbing against the front cover while the tensioner was loose. To clarify, the inner 1/4" of the width of the timing belt (the portion closest to the block), not the thickness, had been shreded.

That said, what I’m hearing from others both here in this forum and from mechanics is that the tensioner is commonly replaced when the timing belt is. I asked the acting service manager at Subaru last week if it weren’t common procedure to replace the tensioner at the same time as the timinig belt. He claims not and says he’s replaced maybe three tensioners in his service career, and many more belts. He claims it’s not a common replacement item. Seems to contradict common sense.

The car has been running smoothly and well with no noticable noises until the the tensioner failure. I asked the Toyota dealer to replace the timing belt when we bought the car specifically to avoid the kind of damage which has now occurred (bent valves). They replaced the belt and seals once, then subbed the job to Subaru after we brought it back in because a bad seal was apparantly leaking oil on the belt. I spoke with the Subaru service manager at that time and he assured me that they were the pros and would get it right, and that it wasn’t uncommon for other shops to have problems with timing belt replacements on this particular engine.

The Toyota dealer has been very cooperative in taking care of a lot of service on this car gratis once brought to their attention, includiing a major transmission component, but that’s a whole 'nuther story. When my wife spoke with them yesterday the Toyota service rep said if we talked with their manager he might offer to pay for half of our half of the cost of the head and valve work. The post to this thread by OK4450 indicates that it’s common to replace the water pump at the same time as the timing belt and tensioner. I’m wonderiing now whether we ought to have that done as long as we’re going through this.

The Subaru service manager is supposed to be back in this morning and I’m going there as soon as I finish this post. More later…


http://www.autozone.com/R,APP1111329/vehicleId,2386801/initialAction,partProductDetail/store,1140/partType,01155/shopping/partProductDetail.htm This is the Web link to Auto Zone. It shows 3 timing belt guide rollers and the tensioner roller.
The timing belt tensioner is a spring loaded piston which has engine oil pressure acting on it when the engine is running. The tensioner pushes against the roller which pushes against the timing belt. The Chilton’ s Repair Manual does instruct to remove this tensioner and test it under varying loads. The repair instructions the shop used (or, not) should have included similar instructions. They may be using any of a number of available manuals: alldata.com; mitchelonline.com; the official Subaru Online, or DVD based manuals; etc. You need to find out which, so that, when you cite a recognized authority, you’ll have your gun loaded.

I think that the bolt through the center of the tensioner roller wasn’t tightened correctly. When the engine ran, the roller tensioner couldnt tension the belt, and the timing belt jumped some teeth, and the pistons impacted the (now) out of time valves.


Thanks! You’re right about needing to know what repair manual they use in their shop. They are the only Subaru dealer in 100 mi. and I’m assuming they would use the Subaru factory manual. What I’d like to know is what the Subaru factory manual advises for tensioner test/replacement intervals. I spoke with the service manager this morning and he tells me they rarely replace tensioners and that he’s seen very few failures in his 20+ years of servicing Subarus. I asked him whether the water pump should be replaced as long as they’ve got it apart, and he replied that Subaru water pumps rarely fail, but that he would install a new one for no charge. reading some more posts this morning I’m now wondering whether the cylinder heads could be damaged as well from colliding with the valves. This seems like a terrible can of worms.


I’ll say this. Anything coming from a service manager or service advisor (writer, whatever) should not be considered the final word.
Most service managers/advisors have never been mechanics and generally have a very limited knowledge of auto mechanicals.

This is often where a huge disconnect exists at the dealers. The serv. manager/advisor is the fence between the car owner and technician and what the serv. manager/advisor says may not be what the tech recommends.
It is recommended, especially around the 100k miles range that all tensioners, idlers, and water pump be replaced and this is applicable to all cars; not just Subaru.

Generally if a belt breaks the cylinder heads will not suffer any damage BUT a complete valve job should be done when the heads are removed. Cylinder head valve seats seldom are damaged. Usually the intake valves are the ones that will bend because the intakes are larger in diameter. This causes them to contact the pistons whereas the smaller exhaust valves will clear.

Nonetheless, a complete valve job should be performed while replacing any bent valves and chances are the cylinder heads need to be surfaced. Subaru only allows a max. of .002 of an inch warpage and that’s not much.
Any nicks in the piston tops should be filed or ground smooth because sharp edges can cause hot spots. This in turn can cause severe detonation problems; as in some very loud knocking. Hopefully they will realize this.

Hope some of that helps anyway. :slight_smile:


Thanks! That’s exctly the sort of advice I need right now. I’m not happy that this has happened, but as long as they have to open it up and pull the heads I want to be sure all the bases are covered. Especially since the Sube service manager doesn’t seem to cover them well. When I spoke with the service manager yesterday he said a lot of independent shops will replace the tensioner, pulleys, water pump and oil seal when replacing the timing belt, but that he normally didn’t because he didn’t want to drive the cost up for his customers and scare them off. I guess he’d rather wait for failures like this to really drive the cost up and piss his customers off permanently. I’ll be sure to go back in next week and make sure thhat a complete valve job is to be done. He told me he would be sending both the head and valves to a local machine shop to have the heads resurfaced and valves replaced if necessary. He may have been implying a complete valve job, but didn’t explicitly say so. And nothiing was said about potential damage to the pistons. I’ll be sure to bring that up.


Maintenance manuals don’t instruct the mechanic to replace the tensioners, idlers, or water pump during the scheduled timing belt change. Mechanics do that because those items may fail between intervals. It’s an anticipatory preventive practice. The dealer goes by the guide lines from the franchise with the car maker.


I guess if the dealers go by the guidelines from the franchise with the car maker, and no further, that’s a good argument for using and independent shop. If there’s a possibility of a component failing between service intervals, and the cost of replacing the component is mostly the labor to access it, it seems prudent to replace it, or at least offer a customer the option to replace it, while the front cover is already open and the components exposed. I feel a service manager should at least inform their customers about the options of replacing other components while the front cover is open, and what the potential cost of the failure of one of those components might be. I’d much rather have been informed of that option back in December when they replaced the belt, than be dealing with the damage that has occurred now.

I spoke with my independent mechanic again on Friday. He was the first to open up the front cover after the noise began. He still maintains that the failure was likely due to the tensioner or mounting plate not being properly secured when it was reassembled after the timing belt was replaced back in December. I guess we’ll never know.


Thanks for the link to the Subaru discussion site. I found reference to a good document there on timing belts in Subarus.


You are welcome Dent72. I hope you get this problem fixed and are happy with your Soob.