Replacing timing belt...necessary to replace tensioner?

[eseiler]

Hi Subaru folks!

I will be getting my timing belt changed in my 1996 OB and I was wondering if, in addition to all the seals, what else ought to be changed while we're in that part of the engine. In particular, I was wondering if the tensioner should be changed.

 

 

Thanks!

Damien

[idosubaru]

yours is a non-interference motor so if the timing belt (or an associated pulley) did happen to break it would not hurt the motor. so in those terms it's not as critical to replace pulleys as the 1997 and up motors.

 

the ideal situation is to replace the belt, water pump, oil pump seals, all the pulleys and tensioner and the cam seals. that's the short answer...here's the long answer.....

 

this is a mileage dependent question. over 60,000 miles and the water pump and pulleys should be changed in my oppinion. at or before 60,000 and you could hold off until the 120,000 mile point for the next timing belt to do the water pump and pulleys. but you should inspect all pulleys while it's apart...more on that below....

 

any pulley that has a bearing go out on it will cause the timing belt to fail very quickly. in my experience the tensioner actually seems to degrade less than the other pulleys, particularly the cogged sprocket pulley (the only one with teeth, the others are followers and have smooth surfaces for the back of the belt to ride on). that one always seems to be too loose (lack of grease in the bearings). blindly replacing the tensioner is not the way to go, it should be checked (just spin it, it's very easy to test as explained below). as well as the other pulleys should all be removed and inspected as well. only takes a couple minutes.

 

on 1997 and newer soobs i use only subaru parts since the motors can experience damage due to a broken belt. on pre-97 models with the non-interference motors you can get away with aftermarket parts if you really want to, though OEM is still the best route for this stuff. it's a big job and not a good area to cut corners on , so it is dependent on your financial attitude towards car maintenance.

 

if you want the best of both worlds....not spending loads of money on all new pulleys then the best method is to replace only the pulleys that don't feel good. stop by a dealer and ask to have any timing belt pulley and feel how tight it spins, they don't spin very much at all due to all the grease packed in the bearing. this is how it should feel. one or more of your pulleys will likely be very loose, spin it and it may be loud or it will spin for a long time and not feel tight at all. you will want to replace any pulley that sounds/feels like this. any pulley you install or leave in the motor should feel tight and have no noise to it at all. if the pulley isn't noisey and is tight then it has adequate grease and there is no need to replace it.

 

they sell timing belt kits on ebay for under 200 bucks i believe that includes the belt and all the pulleys/tensioner. they are NOT OEM subaru parts though. but again, you don't necessarily need every pulley just the ones that are described like i mentioned above.

 

if you're resourceful you can even have the pulley bearings replaced by a machine shop. it'll cost 20-50 dollar per pulley to have that done. they may even be able to re-grease them if they aren't sealed bearings but i'm not sure about that. the bearings though can be replaced for sure, but it'll take a machine shop press to do it....unless you're really good. and sourcing the bearings is annoying as well if you've never done it before. easier to just buy the pulleys you need.

 

if time is an issue it would be a good idea to have one of each pulley in hand and install only the ones that are as described above and then return the others that you didn't need.

 

oil pump seals and cam seals should always be done, they are cheap.

[eseiler]

Sorry I should have mentioned the motor type. It is an interference 2.5L engine...so if the belt should snap...I'm in the market for a new car (at least in 75% of cases I've read).

[idosubaru]

okay...what i said was for the 2.2....but all of the above information still applies to your motor except that you should have everything replaced right now. if any of the pulleys are tight and feel like new then they are retaining the grease and no need to replace. i'd say roughly 50 percent of the pulleys need replacing...obviously that varies wildly dependent on a zillion things and mileage but in general....some need replacing and others are perfectly fine.

 

as a side note - timing belt failure does not require replacement of the car or even the motor. only requires a good mechanic. a friend of mine just fixed the valves in the head of a broken timing belt 2.5 about a month ago. it's not that horrible of a job...the only hard part is finding an honest mechanic willing to pull the heads and fix it. most likely will see bent valves, pistons should be fine. replace the valves and be on your way, much better than replacing the motor or the car. and if done right you've got a great motor ready for another couple hundred thousand miles.