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2011 Outback 2.5i 6MT Ruby Red Pearl
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Discussion Starter · #1 ·
Hello,

Every time I do periodic maintenance on my 2011 2.5i 6MT, I get this nagging question in the back of my mind.

What is the clutch fluid change interval?

It's not in the maintenance booklet or the service manual, so it didn't get added to the maintenance minder software I use on my phone.

Since it's just brake fluid and a similar procedure is used to change it out, do I just change it at the same time as the brake fluid?

I've already changed my brake fluid once (fall 2012), but I did it according to the "severe" conditions schedule (15 months or 15K miles, whichever is first: always months for me) since I'd driven many miles on dusty, steep, mountain roads in extreme heat during that interval.

My unchanged clutch fluid is about the same color (slightly darkened yellowish) as the brake fluid that I changed out last fall, so, while it's very unlikely to be anywhere close to a damaging condition at this point, my gut says it should probably be changed.

What do other manual driving Outback owners who do their own maintenance think?

Andrew
 

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2006 Outback 2.5i Limited 5MT, 1984 Porsche 944
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276 Posts
Here are my thoughts:

Brake fluid goes bad for two reasons: water absorption, and contamination from the seals and linings. Water is only absorbed if the level drops and moisture containing air fills the empty void (such as when brake pads wear down). The other aspect is a factor of time and use (the more the seals scrape against the sealed surface, the more the seals wear).

I'm not sure why severe use would constitute changing the clutch fluid more often. I doubt you use the clutch any more driving off road than you do driving through downtown. And unlike brake pads, the clutch system volume doesn't change as the clutch wears down.

What I said is wrong if air is pulled into the reservoir each time the clutch is used. If that is the case, then dust could be introduced into the system each time the pedal is pressed. I don't think that is the case though.

Based on that, I'd say you're fine for at least 30k, if not 60k miles. Mine is the original at 103k.:eek: That'll change soon though, my motive bleeder just came in!
 

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232 Posts
Hello,

Every time I do periodic maintenance on my 2011 2.5i 6MT, I get this nagging question in the back of my mind.

What is the clutch fluid change interval?

It's not in the maintenance booklet or the service manual, so it didn't get added to the maintenance minder software I use on my phone.

Since it's just brake fluid and a similar procedure is used to change it out, do I just change it at the same time as the brake fluid?

I've already changed my brake fluid once (fall 2012), but I did it according to the "severe" conditions schedule (15 months or 15K miles, whichever is first: always months for me) since I'd driven many miles on dusty, steep, mountain roads in extreme heat during that interval.

My unchanged clutch fluid is about the same color (slightly darkened yellowish) as the brake fluid that I changed out last fall, so, while it's very unlikely to be anywhere close to a damaging condition at this point, my gut says it should probably be changed.

What do other manual driving Outback owners who do their own maintenance think?

Andrew
Hi,

The rule of thumb appears to be every two years. Brake and clutch fluid is susceptible to time, not just miles, typically. On some cars, the service interval is thus specified. I follow the two-year rule.
 

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2011 Outback 2.5i 6MT Ruby Red Pearl
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413 Posts
Discussion Starter · #4 ·
Thanks for the input so far.

Everything except the reservoir is a sealed system, so the only air exposure is at the reservoir. I don't ever open it, but I'm pretty sure it's just a plastic lid on a plastic tub.

I don't think the reservoir is air tight (no vacuum seal), so there's bound to be some gas exchange over time just from simple diffusion due to temperature, pressure, and humidity changes.

I usually drive in very low humidity regions (desert and other arid climates), so it probably wouldn't pick up as much water as Florida or other humid areas.

Since it's not directly a safety issue like the brake system, I don't think it warrants "early" changes, regardless of driving conditions. It's extremely unlikely that the clutch hydraulics will fail catastrophically if the fluid is old, but otherwise clean. It's a pretty small and simple system, unlike the brakes.

Right now, I'm leaning towards 3 years. I don't put enough miles on this car for the mileage to be the deciding factor. In 3 years time, I'll only rack up about 20K miles.

Healey3000, is there something you can direct me to that might explain why 2 years is the rule of thumb for clutch fluid or is it just experience or an old habit?

Andrew
 

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2013 Legacy Lim CVT Car: 2011 OB Prem 6MT Car: 2006 Miata GT 6MT mc: 2003 Honda GL1800A * Reunite Gondwanaland *
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3,565 Posts

One of the primary concerns for brake fluid is that water absorption
lowers the boiling point. Boiling point is a non-issue for the clutch.

...don't sweat the small stuff,

Looby

 

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Thanks for the input so far.


Healey3000, is there something you can direct me to that might explain why 2 years is the rule of thumb for clutch fluid or is it just experience or an old habit?

Andrew
Hi,

I've been a long-time BMW owner and they have always preached the 2-year rule. I would agree that that it's not nearly as critical with the clutch fluid as it is the brake but if you are doing four wheel cylinders, what's an additional slave cylinder? Plus, a pressure bleeder makes the task trivial.

I have heard that other manufacturers have a similar recommendation but without hard evidence before me, it should at best be considered anecdotal.
 
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