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Discussion Starter · #1 ·
Hello,

ive got a 2005 Outback 3.0 with 110,000 miles
have recently noticed small amount of coolant weeping on the
drivers side top portion of rad and hoses.
appears to have coincided with recent cold snap
(not sure if theres a connection but have heard some HG separate
during cold periods?)

hoses are snugged down as safely and securely as possible.
has new coolant, OEM cap/thermostat and hoses.
has never overheated and havent seen any major coolant or oil losses.

overflow reservoir always seems to be within normal range during operation and
sitting. fans seem to be operating properly.

am going to get it hydrocarbon tested soon.
money is very tight but wondering if there are
any other tests i should do to possibly rule out HG.
pressure test, leak down,compression etc etc
am praying these arent crazy expensive and or necessary.
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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if you have even the slightest inkling of a coolant problem - look in the radiator for coolant level - DON'T trust the overflow level to indicate correct coolant volume.

are you saying it looks like coolant is spraying around chaotically? or some residue at hose connections or ....? Is the residue near the overflow hose's connection at the radiator's neck?


Blackstone and Polaris are labs that might test for combustion products in a sample of coolant.
 

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2005 OBXT Limited, VF37, STI intake, 5MT
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Like @1 Lucky Texan said, does it look like a spray pattern from somewhere? Or is it running down and dripping?

You may have some hairline cracks that develop near the upper hose nipples on the OE radiator due to age. If you cannot visually see the source or it's too messy, you can purchase a UV-reactive dye from most auto parts stores (or online, like Amazon) and a black light bulb for total under $10. Pour in the dye, run the car. At night it will make clear the path of the coolant leak.

But I would not panic about HG problems. With no other signs (not puking from the overflow, no overheating, no loss of cabin heat), I'd say it was an external leak.
 

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Discussion Starter · #4 ·
thanks for the reply LT.

coolant level in the rad is good, no major losses there.

the coolant seems to be weeping from the two
top hoses and cap. no erratic spraying. more indicative of weeping.
noticed coolant residue along the top of rad
along the drivers side
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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eh....10 year old hoses....you might consider a close inspection as mentioned above, new hoses with screw clamps (check them after a few months, then tighten a little every 3-5 years or so)

I like the GEMI clamps - narrow, rolled edges but pricey

I also put a coupla small zipties on the overflow hose at the rad's neck. offset the connector. I've had weeping there on one of my soobs plus, I don't want an old hose to allow air to be pulled in instead of coolant from the bottle.

to me, too soon to blame headgaskets - but be vigilant!
 

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Discussion Starter · #6 ·
thanks for the replies guys.

more i think about it..there is a very slight loss
in the overflow. not a crazy amount ~ 1/2’ over 1 month time frame.
rad level is good.

when i put new hoses on last yr i used
those worm gear clamps and retightened
after about 6-8 months. id be afraid to tighten anymore.

think the rad is only 3-4 yrs old. as there was a recall I believe
and this one replaced the former. (not sure what the issue was)

thats good to hear that its preliminary to think HG
based on symptoms.

car def has adequate heat in cabin (iam in Canada lol –21 this am.)
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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hmmm...it does seem like there could be a crack. I'd follow roughdiamonds advice , there could be a crack or pinhole.

you could also try the Subaru Coolant Conditioner (repackaged Holts rad weld leak stop) , it has helped with dripping/weeping. Install ONLY per directions on bottle. No more than one bottle.

good luck
 

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2008 Outback 2.5
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Get yourself a coolant pressure test kit at your local auto parts store. Most of them have a loaner program where you pay for the tool or kit (deposit) and get your full money back when you return it. Some give you 48 hours, some give you up to 90 days.

Then take the radiator cap off, put the correct adapter on the radiator and pump it up with a hand pump. You will probably see where the leak is at this point

Autozone's $30 deposit pressure test kit:



Autozone's newest $260 deposit pressure test kit (ouch!)



 

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The typical failure mode of OEM Subaru radiators is the seal between the aluminum fins and the plastic end-cap. Typically, the leaks are seen starting around 100K miles.

This seal will start to leak a little antifreeze in VERY COLD temperatures.... then, as the seal deteriorates, it will leak at other times.

The ONLY way to fix it is to replace the radiator (about $80 part). It took me about 30 minutes to replace my radiator which included draining the antifreeze and refilling with "Asian Blue".


BTW: It is my STRONG belief that some people who have encountered "head gasket failure" did not notice low antifreeze due to this seal failing and kept driving the vehicle.
 

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'04 Outback, 2.5 H4, 4SPD Auto, Cold Wx PAckage, 01 Dakota QC 4WD, 14 Equinox LT
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Yep, mine has that leak around the tank to core crimp. As with all my vehicles, all fluids that can be checked are at each fill up. Once the car warms up, problem ceases. As you mentioned only seems to happen on cold AM temps. Is Denso the recommended replacement from Rock Auto?
 

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Does it have the original constant torque clamps or screw clamps? My experience has been that the constant torque clamps do a much better job of sealing especially when the weather gets cooler.
You are correct about the constant-torque hoseclamps being able to withstand large temperature swings while maintaining seal..... however we are not talking about hoseclamps.

Instead, we are talking about the RADIATOR ITSELF leaking where the plastic end-tanks are crimped onto the aluminum fins. After about 100K miles, the seal in this area starts to fail. First, it starts to leak when engine is cold (below 30F) and reseal when engine heats up. It is frustrating to isolate this kind of leak because one will see antifreeze droplets around the engine-bay... but no specific point of leakage.
 

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As brucep said, the seal at the top (aluminium to plastic seam) are common on all makes and models for a leak spot.

It is also common for them to develop hair line cracks right next to the upper radiator hose.
Go in and rent a pressure tester, it will tell you where and how bad the leak is.
 

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Discussion Starter · #14 ·
thanks for all the help guys! really appreciate this.
@brucep your right on with where the leak is happening (aluminum to plastic seam)
have noticed the two top hoses are weeping a bit as well but like dougmac figured
maybe with the extreme cold temps and the screw clamps I have its not getting really good seal.

will get it pressure tested soon
 

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It's fairly normal for rad hoses to seep a little at the connections in -20 temps. They usually stop when warmed to operating temp.
 

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Discussion Starter · #16 ·
had it pressure tested and it does have a leak.

only had the vehicle just over two years and soon after acquiring it
replaced the coolant (Asian blue)as well as new oem cap and t-stat.

interestingly the t-stat that came out was an aftermarket stamped with
170 F (76C) the spec oem one is an 86

few mechanics ive spoken to say 10 degrees wont make any difference
but ive got it im my head its running hotter.
the difference in the cabin heat is substantial comparing the two t-stats

as i look back to when i got the vehicle (76c t-stat)...there was never any weeping of
coolant.

while iam going to replace the rad is there any logic in using the 76 t-stat?
or will running it cooler introduce many other problems?
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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I would only use OEM or Stant Xacstat

it isn't just the temp, the OEM has a larger wax capsule - like for reasons involving hysteresis (?)



 
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