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differences in timing belt tensioners


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I bought what I assumed to be a 97 dohc 2.5 out of a 97 gt wagon to put in 97 gt.The tensioner is of the single retaining bolt,hydraulic type which I am told is of a later model.My question is when did they change and what other concerns are there?I'm doing head gaskets,timing idlers,seals and such.Both vehicles are autos.Thanks for any input.

Rusty

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1997 is the year they changed them and it was mid production year. If you change the bracket behind the tensioner and idler assembly you can use whatever system you want.

 

Despite what people will tell you, there isn't an advantage to either one. Both are just as good so long as they are serviced and installed properly which is key.

 

The old system must be moved over and then the tensioner bolted to the bracket during timing belt procedure. The new system can't be tensioned in a vice properly and needs to be retracted in a matter of 5-10 minutes, slowly, with even pressure.

The older style one can be retracted and pinned in a vice but again, very slowly. Easy to blow the seal on either one.

 

I say there is no benefit to either at this point because the old kind is just that...quite old by now.

The new system you get a fresh bearing with a tensioner in one unit. I replace this style every time unless the customer declines it. If you have a tensioner failure its far cheaper to buy a new tensioner than the old tensioner and bearing.

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i'm not sure which tensioner you have . hard to tell form your description.

 

the old style is a 2 piece unit, the pulley on a cam lobe type of thing and a small hydraulic piston about 4" long. the new style is a one piece unit with the pulley and piston built into one, sort of.

 

in theory, 98 was the new style and 97 was the old style, but the actual change date may have been slightly before or after the actual model year change date.

 

the old style is generally accepted to be longer lasting, the pulley should be changed at every interval but the piston does not need to be changed unless it leaks or it will not perform. the new should be changed at every t-belt interval.

 

search for ''subaru timing belt kits'' on ebay by ''theimportexperts''. they have good t-belt kits for a good price which lots of folks here recommend. you can see the two different types.

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the old style is generally accepted to be longer lasting, the pulley should be changed at every interval but the piston does not need to be changed unless it leaks or it will not perform. the new should be changed at every t-belt interval..

 

And this is exactly my point. Its a 15 year old timing component. I would agree with you that its a very reliable component but its hard to beat a complete new unit with new bearing.

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glad you said that Shawn. this is a good thing to check into. I searched a little to see trends (or not) on these tensioners. there were more newer style tensioner failures. older ones have higher age and mileages, which suggests the issue could be worse than the feedback indicates. but no doubt a large amount of failures are due to trying to reuse.

 

the newer style tensioners that i've seen fail never caused the belt to jump teeth. maybe they're less prone to that? who knows, too many variables to keep track of but for me maybe it can be said that the old style is a better option to reuse on my non-interference daily driver anyway. i'm more forgiving of the new style after some sifting.

 

the real issue for me is that i'm around too many college students....15 all you can eat chinese buffets :slobber: or a tensioner? :lol:

 

while i was looking for trends this was funny (in an understandable kind of way), looks like your subaru experience has showed you something

Too bad they didnt stay with the old kind. (89-97 or so). Those RARELY failed.
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the newer style tensioners that i've seen fail never caused the belt to jump teeth. maybe they're less prone to that?

 

any chance this was part of subarus thinking which led to the re-design?

 

any chance that the ''slapping'' / knocking sound that some make just prior to failure was designed into the unit to help prevent or at least indicate imminent failure?

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I personally prefer the older style even if I have to buy a new one (about $75 for the tensioner on ebay). Due to the higher rate of failure and the slapping/superceeded bracket issues with the newer one's I just would rather use the piston style tensioner. I have never had to replace one - they seem to last the life of the engine which is good enough for me.

 

As Shawn mentioned - I would not consider doing the timing belt on a '98+ without also replacing that tensioner and possibly the bracket as well if it's one of the superceeded units.... this adds to the cost of the timing belt job and in my experience the '98+ cars are ALWAYS more expensive to do the t-belt's on.

 

Best combo IMO is the early tensioner, 105k belt (CA belt for older models), and all new idlers.

 

GD

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