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1997 outback, 1998 out back, 2006 Outback 3.0r L. L. Bean, 2012 Outback 3.6R
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Discussion Starter #1
Hello
I have a 2006 Subaru Outback LL Bean, 3.0 with about 225k miles on it. It runs great, no issues at all. About a month ago on a trip, I stared noticing that the temp gauge was rising above normal. This is not my first Subaru and I have replaced several head gaskets on the older 2.5 model engines. I knew that this heating up was not normal, and I stared to look into it. I was loosing coolant someplace. Ar first I suspected a head gasket, but I could not smell any exhaust in the overflow tank, and the oil was fine no coolant in the oil. Yet nothing was leaking on the ground that I could see. I dd a pressure test and it held 25 lbs for over 30 min when I stopped the test. Topped off the radiator and overflow and just drove it, paying attention the the gauge, coolant level and leaks.

Over several days, I noticed I was still loosing coolant, and I was starting to see it on the ground etc... I have got it in my shop currently. Have the bottom plastic shroud off it and I can see it has several small oil leaks and evidence of coolant leak. Filled up the coolant in the radiator and half way in the overflow tank and let the motor run for over half an hour or so, looking for leaks underneath it with the shroud removed. I wiped up all the places it seemed to have dripped from, but did hot see any leaks. I saw lots of places it could start leaking from all the rusted array of metal coolant tubes going to the motor, oil cooler etc. But nothing dripping. Sure looks like its leaking some place in front of the motor, or the radiator. Water pump

So I am here looking, reading and asking. Seems to be a lot of places on the bottom of the radiator that could be leaking. Right where the aluminum meets the plastic bottom of the radiator. Also is there a kit that you can get that has all the replacement hoses and metal tubes that are rusting currently?

Any help would be greatley appreciated.

I think I am going to leave the shroud off for a while and drive it and see if I can pin point the leak better. I know this shroud directs air flow and keeps debris out of the motor. But I think I can drive it for a week or so with out the shroud installed.
Thanks!

Greg
 

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1997 outback, 1998 out back, 2006 Outback 3.0r L. L. Bean, 2012 Outback 3.6R
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Discussion Starter #3
there is a weep hole for fluid to escape if the water pump seal leaks.
Thanks for that.

I will look closer at the water pump, but dont think it is the pump. I am suspect of the radiator being bad, but only because I see some green residue on the bottom of it, there is some corrosion around some of the lower fittings. Also some "green" on the motor but I think it got blown onto the motor and then down and back and drip out someplace from the lower shroud, which is where I was seeing coolant on the ground. I am going to drive it a few days (shroud off), and place a large piece of cardboard below it when I get to the house I am working on and see if I can better locate the leak. I may do another pressure test today, but the last one yielded nothing... and after running it for a while while at operating temp in the garage, no leaks appeared. Hard to find a leak if it does not leak. :|

Gonna keep looking on here. Seems I read a while ago about someone with this type problem. Ended up being some of the different metal tubes that hug the motor and go to various places. Mine do not seem to leak, but man are they rusty where the connect to the hoses. Anyone know where I can find out the part numbers for these? Think I want to replace them while I am at this.

Thanks
 

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usually, pressuring the system by hand (I think parts stores loan-out a kit) will help guide folks to any leaks.

crimped-on tanks, hoses, crossover pipes.....there's plenty of places that could develop a leak.

it's a very good idea to maintain the correct level in the overflow bottle, but ALWAYS check in the radiator for actual coolant level - even more important if you are having cooling-rlated issues.
 

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1997 outback, 1998 out back, 2006 Outback 3.0r L. L. Bean, 2012 Outback 3.6R
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Discussion Starter #5
usually, pressuring the system by hand (I think parts stores loan-out a kit) will help guide folks to any leaks.

crimped-on tanks, hoses, crossover pipes.....there's plenty of places that could develop a leak.

it's a very good idea to maintain the correct level in the overflow bottle, but ALWAYS check in the radiator for actual coolant level - even more important if you are having cooling-related issues.
Thanks, agreed and I try to keep overflow in middle and radiator topped off while I have been adding coolant. May not be burping it all the way. Done a pressure test, will do another one today. I am just wondering if it has to get 'hotter' for the leak to show. I am going to look at the between radiator and condenser to see if its got debris in there. From what I have seen of the radiator it looks pretty clean. but I never took any thing off to see directly.

I am wondering if it is overflowing at the over flow tank and getting on everything that way. Will report back once I drive it some more and investigate a little more. I do know I need to replace all the lower tubing associated with the cooling system... this will be leaking soon if its not already....
 

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Discussion Starter #6
I am currently on my second pressure test. First one help just fine for over 30 mins. I have a different pressure tester than I did with the first test, so I am still learning it, not a big deal but its seems touchy.... This one is mine. Also I tested the cap. The cap was BAD, VERY BAD, would not hold even a pound for a second... So that could be the whole problem. Also It looks like the radiator that is in it is not original. It is a denso, but I am not sure what the original one would be labeled if anything. I tried to see the number a little better and whipped it all right off! ****. Well It held for over an hour at 23 lbs. So again the pressure test passed just fine. I am really thinking that the cap was the issue. I will know tomorrow. The job house is about 45 mins away. I always would have to top the coolant off on the way home, maybe a quart or more. Ill put something under it, card board etc, so I will know if it leaks at all. BUT.... if it was the cap, am I correct in thinking that it would just blow by the cap, when it gets hot, and out onto the motor/road etc and maybe some catch in the plastic shroud on the bottom until lit leaked out onto the ground?? (I smell coolant when I get out out of the car most of the time.)

I am still planning on doing all the tubes I can see on the bottom, they are just ticking bombs as far as I am concerned.
 

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It will blow past the cap and into the reservoir where it will eventually overflow unless it's blowing past the cap seal/gasket where it will simply leak out the sides of the cap.

If you can't hold 1 psi, your coolant system is at essentially 0 psi gauge pressure and your 50/50 coolant boiling point is 223F rather than close to 268F at 16 psi.

https://durathermfluids.com/pdf/techpapers/pressure-boiling-point.pdf
 

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1997 outback, 1998 out back, 2006 Outback 3.0r L. L. Bean, 2012 Outback 3.6R
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Discussion Starter #8
It will blow past the cap and into the reservoir where it will eventually overflow unless it's blowing past the cap seal/gasket where it will simply leak out the sides of the cap.

If you can't hold 1 psi, your coolant system is at essentially 0 psi gauge pressure and your 50/50 coolant boiling point is 223F rather than close to 268F at 16 psi.

https://durathermfluids.com/pdf/techpapers/pressure-boiling-point.pdf
Thanks for the reply Rocket 1. Good info. Headed out now will report back on what I find today after the drive.
 

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Ideally you use a Subaru cap.

Those metal lines in front of the vehicle and the one snaking back on the drivers side are prone to rust and leak. The rust can sort of be multi-layered rather than a hole and leak inconsistently depending on ambient conditions. Maybe it only leaks when it's hot/under pressure.

If the leak isn't obvious - like the cap appears to be, those metal coolant lines or your leanings towards the radiator would be my first guess.

How sure are you that it's a new radiator?
 

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Discussion Starter #10
Ideally you use a Subaru cap.

Those metal lines in front of the vehicle and the one snaking back on the drivers side are prone to rust and leak. The rust can sort of be multi-layered rather than a hole and leak inconsistently depending on ambient conditions. Maybe it only leaks when it's hot/under pressure.

If the leak isn't obvious - like the cap appears to be, those metal coolant lines or your leanings towards the radiator would be my first guess.

How sure are you that it's a new radiator?
Hey Idosubaru, thanks for the comment! I am not sure it is a new radiator at all. I just saw the Denso name and thought it was new or at least different than stock. I replaced the cap with a Stant cap. I will order a new Subbie cap.

So to report about yesterday: I live about 70 miles south east of DC. You may have seen the historic flooding that occurred yesterday. We did not get that, as we are very rural, but I can conclusive report that we got in excess of 6 inches of rain for the day! The reason that is significant is that I could not see any leak because of all the rain running down the driveway where I was working. Prior to leaving the job site, (rain had stopped) I cked the over flow tank and the radiator. Radiator was low, and I added about what I usually do a quart or so. The over flow tank was full, and it was not how I left it the day before, after the pressure test. So Idosuparu, I am still suspect of the radiator, and your description of how the various tubes can leak matches what I think is going on. So is it logical to think something like this: The car heats up, and does it thing, pushing the coolant into the over flow tank etc. It continues to get hot, and whatever leaks, leaks, pushes out more coolant and depressurizing the system so that when it does cool, it does not suck the coolant back into the radiator? I guess it would cause overflowing of the over flow tank too.

I am going to order a radiator and the related tubing along the motor that are toast. Anyone know of a good place to accurately determining what exactly they are and a part number? I have looked and have found some but sure of all of them. Thanks for the help Idosubaru!

Greg
 

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Hey Idosubaru, thanks for the comment! I am not sure it is a new radiator at all. I just saw the Denso name and thought it was new or at least different than stock. I replaced the cap with a Stant cap. I will order a new Subbie cap.

So to report about yesterday: I live about 70 miles south east of DC. You may have seen the historic flooding that occurred yesterday. We did not get that, as we are very rural, but I can conclusive report that we got in excess of 6 inches of rain for the day! The reason that is significant is that I could not see any leak because of all the rain running down the driveway where I was working. Prior to leaving the job site, (rain had stopped) I cked the over flow tank and the radiator. Radiator was low, and I added about what I usually do a quart or so. The over flow tank was full, and it was not how I left it the day before, after the pressure test. So Idosuparu, I am still suspect of the radiator, and your description of how the various tubes can leak matches what I think is going on. So is it logical to think something like this: The car heats up, and does it thing, pushing the coolant into the over flow tank etc. It continues to get hot, and whatever leaks, leaks, pushes out more coolant and depressurizing the system so that when it does cool, it does not suck the coolant back into the radiator? I guess it would cause overflowing of the over flow tank too.

I am going to order a radiator and the related tubing along the motor that are toast. Anyone know of a good place to accurately determining what exactly they are and a part number? I have looked and have found some but sure of all of them. Thanks for the help Idosubaru!

Greg
I hope I'm wrong, as you do, but that sounds more like headgaskets. I'd hold off on throwing more parts at it in case it ends up needing new gaskets or an engine.

Did you buy this car within the last year?

After topping the radiator and overflow off:
1. start the car and let it idle and look in the overflow tank for bubbles.
Do you see any?

2. After a short drive (preferrably before any overheating or fluid pushes out of the overflow) - pop the hood with the engine running and look in the overflow tank for bubbles again (not the radiator when the engine is hot obviously).

Keep repeating those checks and see if there are any bubbles.
 

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Discussion Starter #12
I hope I'm wrong, as you do, but that sounds more like headgaskets. I'd hold off on throwing more parts at it in case it ends up needing new gaskets or an engine.

Did you buy this car within the last year?

After topping the radiator and overflow off:
1. start the car and let it idle and look in the overflow tank for bubbles.
Do you see any?

2. After a short drive (preferrably before any overheating or fluid pushes out of the overflow) - pop the hood with the engine running and look in the overflow tank for bubbles again (not the radiator when the engine is hot obviously).

Keep repeating those checks and see if there are any bubbles.

Quick reply, as I am off to work... Had the car a couple years now. Got it with about 210k on it. I have seen bubbles, but thought it was probably just air getting out after being low on coolant... I saw bubbles yesterday, AFTER I turned the motor off and nothing was running ..... I do have a block test kit that I bought for a different car I was working on but never used... Ill look at it again today... HG I sure hope not.... thanks
 

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Quick reply, as I am off to work... Had the car a couple years now. Got it with about 210k on it. I have seen bubbles, but thought it was probably just air getting out after being low on coolant... I saw bubbles yesterday, AFTER I turned the motor off and nothing was running ..... I do have a block test kit that I bought for a different car I was working on but never used... Ill look at it again today... HG I sure hope not.... thanks
Hopefully I'm wrong and communicating with a keyboard is no way to diagnose a car but I'm pretty confident with those limitations that you're looking at headgaskets. Those bubbles are signs of exhaust gases getting pushed passed the headgaskets into the combustion chamber. Coolant leaks through the headgaskets, into the combustion chamber, and gets burnt off, and some exhaust is getting pushed into your cooling system. And it's often a consistent pattern/amount of consumption depending on loads.

Those chemical block tests can give false negatives.
 

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Discussion Starter #14
Hopefully I'm wrong and communicating with a keyboard is no way to diagnose a car but I'm pretty confident with those limitations that you're looking at headgaskets. Those bubbles are signs of exhaust gases getting pushed passed the headgaskets into the combustion chamber. Coolant leaks through the headgaskets, into the combustion chamber, and gets burnt off, and some exhaust is getting pushed into your cooling system. And it's often a consistent pattern/amount of consumption depending on loads.

Those chemical block tests can give false negatives.

Hey Idosubaru,

Thanks for taking the time to consider this issue. So I got home and let the car run while I popped the hood and then looked in the overflow tank. Steady ******* stream of bubbles... could not smell exhaust gas in them, butI doubt that there would be any air left in the system, after driving some 45 mins at 60 mph.

So it does make sense that it could be the HG failure. No real sign of a leak anyplace on the motor, but there is places it could or will be leaking as I have said on the rusted tubing. So I do have a 3.0 in the garage on a stand that someone gave me. Said that it has a head gasket leak.... its got less than half the miles mine does on it.... I dont remember the year of it...y.. how can I find out if that will work in my car? (if I think it will be an ok motor to repair)

Thanks!
 

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Discussion Starter #15 (Edited)
The issue of coolant loss has not resolved it self. Still same deal, coolant low after 45 min to an hour drive. Top off prior to driving. repeat. So yesterday I put the car in the garage. Got my yellow coolant funnel inserted in the radiator and attempted to burp the system as best I could... took it for a short drive, maybe 10 miles. Got home popped the hood with it running and there were no bubbles in the overflow tank...I did this again today but sorta in reverse. topped off the radiator, over flow a bit above normal so I can see any bubbles etc. I put the car on my lift and let it run for over an hour. Prior to starting it I attempted to inspect for obvious leaks. I wiped off any area I thought might be leaking etc.... I am still suspect of the radiator. The bottom area where the aluminum is crimped to the plastic has residue there, looks like cooked or dried coolant. Started it up and watched for leaks, bubbles in coolant tank and temp gauge. Temp gauge climbed nicely to normal operation. No bubbles in tank at any time, none while on the lift. Nor did the coolant level rise much if at al. (I would have expected it to just for the expansion of the coolant) I looked for leaks and found a couple small weeping leaks at transition to some hoses and the metal tubes. never got hotter than it was supposed to do, and never saw any bubbles. Fans seemed to work ok, came on and off, kept AC off as well. Kicked up the RPMs a bit to between 1500 and 2k. Kept it there for two to three minutes. Checked the over flow, no bubbles. After an hour plus of the engine running on the lift, mostly idle, I took it for a drive. Not far, just a few miles and back. Got out and looked at the over flow tank, and did see a few bubbles, I watched but not a constant stream. I watched a bit and they did stop...I put it on the lift again and looked for leaks. There was coolant dripping from a few places around the area of the overflow tank, below it from the radiator hose and the area around it. When I looked at the overflow tank, I saw no bubbles and I could not tell if it leaked out the tank or not. The overflow tank lever was raised but not over flowing. Oh and I cked the exhaust for signs of coolant being burned/blown out etc... but I did not smell it or see any coolant (would I see green coolant?). Some normal condensation was all.

I do not think any of this is conclusive of a head gasket leak. I know the coolant is going someplace. It may be coming from the over flow tank.... But I guess the question is why. If the head gasket is leaking, , then there should be constant bubbles coming from the radiator into the over flow right? In the other 2.5 ez-25's I have done they all had that symptom and I could smell exhaust in the over flow.

If the radiator is compromised then it would not pressurize like it should and then the coolant would boil and push into the overflow tank.

I ordered a new radiator last week... Should be here tomorrow. I will install it, deal with the weeping leaks and go from there. I almost pulled the trigger on a motor this am, but thought a couple more hours to ck this may be worth it. (Found a motor with a trans included for about 1200 bucks... So if I do need it, hope it is still there. )

So am I way off base on my thinking of this situation? Or does all this mean head gasket and I just don't see it yet?
 

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Discussion Starter #16
Also meant to add/ask this:

Have done several pressure tests on this cars cooling system. All of them held pressure. longest test was just over an hour. If it were a head gasket or even a bad radiator, how is this possible? In the case of the radiator, maybe the thing is full of sludge or who knows what. That would limit cooling capacity and could cause the issue I am having. But, and I am asking, if the head gasket was blown, it would leak at that spot and loose pressure and the test would indicate a leak someplace. If I can remember, I am going to put the tester on it over night and do a 12 hr or so test and see what that shows.
 

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Discussion Starter #17 (Edited)
@idosubaru
Been reading, leaning things etc, found this thread: https://www.subaruoutback.org/threads/yo-yo-coolant-h6-3-0.305450/#post-3443210
Does the situation I am having fit under what your said in that thread? You said:

"Most likely initial head gasket failure signs.
Maybe it's a simple overflow hose, radiator is damaged not allowing the cap to properly seat, a leak somewhere. Make sure to rule that out.

I know it's not performing bad, loosing compression, mixing oil/coolant, leaking externally, coming out the exhaust. This engine doesn't fail that way. But people routinely throw those out as incorrect confirmations that the head gaskets are good.

When they first start to fail the only symptom they have is pushing exhaust gases into the coolant. And it can be meager amounts and only happen under certain conditions - usually under load like interstate driving, mountain driving, towing, or high heat with the A/C on. Given that ambient temps are so much lower than ICE temps and the temps are regulated by the tstat for a set temperature that surprises me it can make a difference, but it does and I've seen it multiple times. I've seen them have zero issues - none at all - over the winter - but have issues in the summer.

But it's usually an initial head gasket sign - I've seen them take about 2 years to get worse so you might be able to ignore it for a long time, replace a lot more parts, be puzzled until it gets egregious, start to overheat, loose significant amounts of coolant after 2 years.

When it's bubbling a 5 gas analyzer (expensive equipment used by only certain shops) can usually track it down if the person using it is good. You're in seattle, All Wheel Drive Auto would probably know how to verify quickly/easily without throwing parts at it:
https://allwheeldriveauto.com/subaru-repair/

All other tests are nearly pointless on initial HG failures of this variety - so make sure you don't waste time on compression tests. Although lockmedic likes pressure tests - is that pressure testing the cooling system @lockmedic? I haven't tried that yet."

So do you think this is where this engine is? Guess I am still hoping its not the HG's
Thanks... I am still curious about the no leak on the pressure test....
 

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I'm curious about this for myself because I'm battling my own h6 issues. I have largely discounted my h6 having head gaskets issues but now, I'm not so sure.

Like you, my experience with h4's and headgaskets yields a coolant system with lots of bubbles in the overflow or radiator spill free funnel. My h6, however, doesn't seem to blow bubbles unless under certain circumstances. I've been trying to track down a way to tell definitively if it is indeed exhaust gases, but, sometimes, after running my engine 3-4k rpms for several minutes, and getting the subsequent temp spike, I get bubbles in my spill free funnel. They're brief, and go away quickly and never return but I do get some.

Again, I don't know if it's exhaust gases, trapped air in the system or localized boiling/cavitation that's causing the bubbles but it's something I've only recently become aware of.

My h6 started "overheating" (meaning 3/4 mark or so on the temp gauge) only after it overheated due to a clogged radiator.

I've wondered if higher temps or rpms caused what little breach there was in the headgasket to get worse--like the aluminum head was expanding just enough or something--if that makes any sense.

$1200 for a engine and trans combo is a great deal. I haven't seen any ez30r's by themselves less than $1200.
 

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Discussion Starter #19
Hey aesthetic.rake

In this thread: https://www.subaruoutback.org/threads/yo-yo-coolant-h6-3-0.305450/#post-3443210
they talk about an over heating situation like a clogged radiator etc, causing a head gasket failure. To me that makes sense. But in my case, I have never had this problem, unless all this is the result of the said cause of original over heating, whatever the cause...

Mine did the same as yours, never hit the red, just at the 3/4 mark was about as high as it got... it was when I was driving hard on some steep hills in western MD going on a fly fishing trip... this was mid May. Been fussing with this ever sense. I think the coolant is over flowing the over flow tank.... oxymoron? And I think the radiator has an issue, clog, or some issue with seams. But not sure what... I am fearing head gaskets, but hoping not... regardless my car has 225k on it and I shot that guy an offer for the motor/trans so we shall see.

Keep me posted as to what your find as will I.
 

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Discussion Starter #20
I put my coolant pressure tester on the radiator last night around 4 pm. I cked in this am prior to leaving for work. It was down a couple lbs, from 23 to about 20.5 or so. I dont think there was a leak, I attribute this drop to the drop in temp from when I installed it to when I read it at about 8 am this am... So again not sure what to think about this situation.
 
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