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2008 OB XT Limited; 2002 Impreza 2.5TS
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Discussion Starter #1
Hi all,

I was looking under the hood, trying to find a place to mount an ATF cooler (that's another thread... ).

I noticed that my top radiator hose was all scrunched together, like it was drawing a huge vacuum.

Turns out that the overflow hose that runs from the radiator to the coolant reservoir was too long, and it had actually sucked itself against the bottom of coolant reservoir, so that no coolant could flow back into the radiator.

So, I cut 1" off the hose and topped off the radiator... Done.

Bimmer
 

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There was a TSB about the overflow hose. #09-52-08, issued 08/19/08. Essentially, as ETC noted -- remove the hose from the reservoir, cut about 20 mm (a bit less than an inch) off the bottom at a 45 degree angle. When the hose is reinserted the lower end of the hose should be hanging down freely and not contacting the bottom.

The TSB also referred to inspecting and cleaning the gaskets and valve on the radiator cap to make sure it is working properly.
 

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2008 OB XT Limited; 2002 Impreza 2.5TS
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Discussion Starter #4
Aha!

Well, it's good to hear that I'm not the only one who's had this happen.

Cutting at an angle makes perfect sense. Maybe I'll pull mine out and cut it again...

Bimmer
 

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2008 OB XT Limited; 2002 Impreza 2.5TS
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Discussion Starter #6
What years were effected by this?
I dunno...

Here's a simple test:

Push down on the hose at the L where it goes into the top of the reservoir.

If you can feel it hitting the bottom, and/or the bottom of it isn't already cut at an angle, then I'd recommend cutting it.

As it is, I think mine now dangles 1/2" above the bottom of the reservoir.
Yes, I know that this means I effectively reduced the reservoir's capacity by 1/2", but that's OK with me...

Bimmer
 

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I know that this means I effectively reduced the reservoir's capacity by 1/2", but that's OK with me...
Yes, far better than the alternative that you noticed. But also, that 1/2 inch represents only a few ounces. Not going to make a big difference. In fact, the bottom of the hose will still be well below the LOW level. Hopefully the reservoir is checked often enough that the level would never, normally, get that low.

Here's the TSB. (I thought I had posted it before but I guess not.)
 

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*** Thread Resurection! ***

Well, I almost blew our virtually new '09 1.5 N/A Impreza two years ago over here and a '09 2.0 N/A Forester reported similar overheating symptoms last year.

This problem must be much more common than what this old TSB implies.

Maybe many of the 2.5 N/A head gasket failures could be attributed to this simple stupid problem: When I was trying to diagnose our intemittient Impreza coolant overflow and overheating problem the symptoms were very similar to blown head gaskets but without any exhaust gas odours when sniffing the radiator after removing the cap while watching bubbles popping up. Without obvious reasons, on the bulletproof closed deck 1.5 N/A engine I have had coolant blown out from the expansion tank and lack of coolant in the radiator every now and then without tracing a pattern for this beahavior. Symptoms went 100% away after similar to the TSB treatment. If only I new this TSB earlier it would have saved me 2 years of head scratching on the issue and I would still trust our Subie...
 

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^ adding to the above: The expanion tank hose was so long it reached the bottom of the tank on our Impreza when pushed in the tank down to the 90 degree bend (easy to do when inspecting the engine bay for anything looking irregular like the hose seating too high in the expansion tank intake hole) and the VIN number of our car is earlier than the ones mentioned on the TSB. As the hose gets softer when up to temperature, I am sure it just got sucked against the bottom and blocked coolant return so the new and clean radiator cap on the new and clean replacement radiator of our car sucked air once more and had the expansion tank overflowing all its content last July, before I finally traced the problem on a too long hose - a clear error of the assembly line that almost caused big trouble for me 2 years ago...

 

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*** 1 year later update ***

Our N/A EL15 '09 Subaru Impreza has been 100% ok after the hose length treatment without a single coolant related hiccup during the past 12 months under mixed running in temperatures from freezing point in Winter to heat waves in Summer.
 

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06 Outback 2.5i
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Good thread. Mine was way longer, 20mm and 45 degree cut actually made it worse - it was facing flat on the bottom of reservoir. I ended up cutting too far and will be buying the updated hose.

New hose is 45162AG02B.
Old hose is 45162AG02A.
 

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It is not a bad thing to have the end of the hose a little off the bottom of the reservoir... this allows for sediment to settle and not get sucked back into the system.

I firmly believe that cutting the tip of the hose at an angle is FAR better than assuming the end of the hose will hang in the proper position for the lifetime of the vehicle.

Do not forget that when the hot, pressurized, coolant blows thru the hose into the reservoir... the end of the hose moves about.
 

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2006 Outback LL Bean 3.0 H6 - 1989 Range Rover Classic
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*** Thread Resurection! ***

Well, I almost blew our virtually new '09 1.5 N/A Impreza two years ago over here and a '09 2.0 N/A Forester reported similar overheating symptoms last year.

This problem must be much more common than what this old TSB implies.

Maybe many of the 2.5 N/A head gasket failures could be attributed to this simple stupid problem: When I was trying to diagnose our intemittient Impreza coolant overflow and overheating problem the symptoms were very similar to blown head gaskets but without any exhaust gas odours when sniffing the radiator after removing the cap while watching bubbles popping up. Without obvious reasons, on the bulletproof closed deck 1.5 N/A engine I have had coolant blown out from the expansion tank and lack of coolant in the radiator every now and then without tracing a pattern for this beahavior. Symptoms went 100% away after similar to the TSB treatment. If only I new this TSB earlier it would have saved me 2 years of head scratching on the issue and I would still trust our Subie...

*** Thread Resurection! *** [AGAIN]


I hope this cutting of hose business solves my issue as this all sounds very familiar to me.....but with the H6.
 

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*** Thread Resurection! *** [AGAIN]


I hope this cutting of hose business solves my issue as this all sounds very familiar to me.....but with the H6.
I hope it works for you as well it did for us: 3+years without the slightest smell of a cooling system problem! :smile2:
If only I had seen this issue before we changed the radiator in vain! Thank gods we did not start a gasket job that would not solve this ridiculous problem!
 

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I hope this cutting of hose business solves my issue as this all sounds very familiar to me.....but with the H6.
well, is the issue resolved for you as well?

3 days ago at my local Subaru mechanic I came along a '09 3.0 H6 5EAT Outback with 400 000 kms on the clock - it was holding up very well but needed some coolant so I had a look and ... the **** hose was all too long since day 1... I informed the owner and the mechanic and 30 seconds later the hose was pulled out-verified too long-modified-put back in its place in about 1 minute total time...
 
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