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EJ25 DOHC timing belt idlers, tensioner


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It's time to change the head gaskets in my '99 Outback (81,600 miles). I'm putting together my shopping list, and I'm wondering about the t-belt tensioner and idlers.

 

In my other vehicles (VW, Volvo), I've always changed the tensioner and idler with the belt. They only cost $26, and no extra effort to swap out.

 

The EJ25 DOHC has 4 idlers (2 pulleys, 1 gear, 1 pulley on the tensioner) with a fancy hydraulic tensioner. Replacing all of them would cost well over $300 from 1stsubaruparts or $244 from Advance Auto (Dayco kit). Yikes!

 

Are the idlers and tensioner normally replaced with the timing belt, or only as needed? What do you guys recommend?

 

I will do the water pump and all seals/gaskets/o-rings I can get to.

 

Thanks!

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As I understand it, replace only if they are noisy by listening against your ear. As for the tensioner, look at the tip of the rod - if there is no big wear and tear from loose tensioner, it is okay.

 

See July 2001 issue of Motor magazine at www.motor.com (and following issues for more tips on t-belt job) - it says they rarely fail...

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Bank on replacing the tensioner, they tend to go "soft" even if they aren't leaking oil.

 

The toothed idler that runs inside the belt often has a noisy bearing at your mileage, so that would be a good one to buy straight off.

 

The smooth idle wheels should be okay.

 

I do understand your predicament, if you take everything apart and listen for faulty bearings, you will need to wait until the new parts arrive.....

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<<It's time to change the head gaskets in my '99 Outback (81,600 miles). I'm putting together my shopping list, and I'm wondering about the t-belt tensioner and idlers. >>

 

 

whats the reason to do the headgaskets? did the engine overheat? at 81K you won't need to worry about anything exept TB and maybe crank and cam seals. Do you have the cam "holding" tool for the DOHC?

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I took my idlers to the mechanic at dealership and asked him for his opinion. As setright said, he suggested replacing the toothed idler. Everything else he said was okay.

 

One idea I toyed with was to buy the idler at local dealership, use it and order a replacement from 1stsubaru. Restock it to dealer....Never implemented it!

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whats the reason to do the headgaskets? did the engine overheat? at 81K you won't need to worry about anything exept TB and maybe crank and cam seals. Do you have the cam "holding" tool for the DOHC?

No overheat yet, but that's only because I'm checking the coolant level at least once a day. It's blowing a steady stream of bubbles in the expansion tank, and the coolant smells like exhaust. The bubbles have been increasing over the last 6 weeks.

 

A new symptom this week: the level in the expansion tank rises, and coolant is not sucked back into the radiator. When it gets high enough, I use a baster to transfer coolant from the expansion tank back into the radiator.

 

I'm carrying extra coolant, checking the levels, and avoiding the highway until I get this fixed (hopefully next week).

 

I don't have the holding tool for the cam sprockets. I'll fabricate something once I get in there.

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Thanks for your input, folks. I think I'll order the tensioner and the toothed idler, and source the smooth idlers locally if needed. Searching other threads and web sites, it seems that those are the two that will need to be replaced sooner or later.

 

The t-belt change interval on this car is 105K miles, and I doubt the original tensioner and water pump will make it to 186,000 miles (that would be the next scheduled t-belt change).

 

I'll check/adjust the valve lash, too, but the shims will have to be purchased as needed.

 

Thanks again! This board is awesome!

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  • 1 year later...

replace sprocket idler

 

mine blew up on the way from michigan to califronia

 

got a timing belt kit with timing belt and all idlers and tensioner from ebay oem parts for 155. local auto part shop wanted 370

 

oh yeah now i am in the process of putting new heads on thanks to that sprocketed idler

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