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Hello,

 

I'm having some coolant weirdness with my 2002 Subaru Forester. I'll give you a brief history of what's been done and what I'm seeing now.

 

In March of this year, I had the head gaskets replaced and the 140,000 mile service done including everything that should be done with that maintenance, timing belt, etc. In April, during a trip from SC to FL, I had to have my radiator replaced. The mechanic did the test that showed the heads were not leaking, I can't remember the name but he put a device in the top of the radiator and showed me the color of the fluid and explained how it should change colors and all that.

 

Since then, I've noticed odd coolant things, most recently with the radiator pushing all the coolant to the overflow tank and not taking any of it back in. This happened once or twice in June, and I took it to my usual mechanic and he could not replicate the problem. I moved from SC to CO in early August and during that drive, the car overheated and all of the coolant was in the overflow tank. I put it on a tow dolly and towed it out here.

 

This week, a mechanic friend and I replaced the thermostat (OEM part), thinking that might be the issue. In the last few days I've driven it with no problems, but I'm noticing that where the hose meets the radiator cap, there are bubbles coming out of that connection with a fizzling sound and a very small but noticeable coolant drip at that connection. 

 

Edit: I should also add that there are sometimes bubbles in the overflow tank. 

 

When we drained the radiator, we kept the coolant and poured that back in as we burped the system. We did not drain the overflow tank and it is definitely still way overfilled, way past the full line, but this is full from before our repair when the problem originally started. It pushed all of that out and didn't take it back in. Now that we've done this repair I've seen the coolant rise and fall, but very little since there is already so much in the tank.

 

Any thoughts on all of this?

Edited by jonnysharp
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Welcome to the USMB.

 

Was the thermostat that you used a Subaru thermostat?  If not, I'd suggest replacing it with a Subaru thermostat.  If you did use a Subaru thermostat I'd say it kind of sounds like head gasket issues.

 

The tester the previous mechanic used was called a hydrocarbon tester/sniffer.  I have one and if the head gasket leak is pretty small it may put enough gasses in the coolant to register in the testing fluid.  You may want to have it tested again for confirmation, but usually bubbles coming from the cooling system are an indicator of head gasket issues.

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Hey Legacy777,

 

It was a Subaru thermostat. I'm no expert on these things, but based on my limited knowledge and Google, it's not showing any other signs of head gasket issues except that bubbling in the tank. The exhaust is fine and smells normal. 

 

Would it not just be something as simple as the hose or the radiator cap? I'm kinda hoping for something simple :/

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Welcome to the USMB.

 

Was the thermostat that you used a Subaru thermostat?  If not, I'd suggest replacing it with a Subaru thermostat.  If you did use a Subaru thermostat I'd say it kind of sounds like head gasket issues.

 

The tester the previous mechanic used was called a hydrocarbon tester/sniffer.  I have one and if the head gasket leak is pretty small it may put enough gasses in the coolant to register in the testing fluid.  You may want to have it tested again for confirmation, but usually bubbles coming from the cooling system are an indicator of head gasket issues.

 

He wrote:

I replaced the thermostat (OEM part)

 

This sounds like it's a blown HG. Do you know what type of HGs they used? If it was anythign but Subaru HGs then they stand a high chance of failure.

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I'm noticing that where the hose meets the radiator cap, there are

bubbles coming out of that connection with a fizzling sound and a very

small but noticeable coolant drip at that connection.

if the hose running from the rad cap to the over flow bottle has a hole in it the rad CAN NOT suck the coolant back into the system.

the coolant is forced into the over flow as designed, but if there is a hole, it cannot create the vacuum needed to suck it back into the rad.,

if this is what is happening i would fix that first.

 

the bubbles are a bad sign, but typically the 02 is not know for internal head gasket leaks.

they usually leak coolant and /or oil to the outside of the engine.

(the 96 - 99 ej25 engine would leak combustion gasses into the coolant creating bubbles in the coolant.)

 

there is a VERY VERY small possibility that the bubbles are caused by lack of coolant , lack of coolant flow, and possibly an air lock preventing coolant flow.

but that is really a small chance given the symptoms.

 

still i would fix the leak , refill the system correctly , including the overflow, and keep an eye on it.

it will either operate correctly or not.

Edited by johnceggleston
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if the hose running from the rad cap to the over flow bottle has a hole in it the rad CAN NOT suck the coolant back into the system.

the coolant is forced into the over flow as designed, but if there is a hole, it cannot create the vacuum needed to suck it back into the rad.,

if this is what is happening i would fix that first.

There doesn't appear to be a hole in the hose. I'm wondering if the hose clamp might be bad? Or just the radiator cap? Again, I just got this radiator replaced in April.

 

I cranked the car up earlier and let it get up to temperature with the radiator cap off to get out any air. The thermostat appeared to open up correctly, the car never overheated. I saw a bit of the gurgling and bubbles from the hose connection and readjusted it. I drove around the block a few times and then parked. When I turned it off I checked the hose and it was not gurgling out bubbles like it was before.

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Just replace the hose that runs to the overflow jug to the radiator (it's cheap) and replace the radiator car as well (that's cheap too)... What are you running for an air filter? and what type of gas do you use? I run a cold air filter and high octane non-ethanol fuel in my 01' Lego just to keep her cleaned out and because of that it increases the engine temp just enough to run a little coolant into the overflow jug, But I don't care it's worth it and it's not bad if i check it once a week, but I also put close to 1,000 miles on the one a week. But I know that is the prob for sure on mine because the head gaskets were redone, the water pump, thermostat and the cap also flushing the system out regularly. But If you run a cold air and/or high octane fuel in a non-turbo scoob that may be the cause..The bubbles are throwing me off though....

Good Luck! 

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I had the same issue (95 Liberty/Legacy) last weekend after I replaced my leaking water pump. I thought I'd "burped" the cooling system correctly, the temp gauge needle slowly climbed to the halfway mark and stayed there, so I went for a drive. The needle remained in the middle of the gauge for the first 20 miles, then suddenly climbed up to the "Hot" mark. Bugger.

 

 

I parked and waited for it to cool (middle of winter here, so it didn't take long) and then lifted the hood. To my surprise, the coolant overflow tank was full, and actually overflowing, judging by the coolant that had been sprayed over the engine and battery, etc.

 

 

I siphoned the coolant back into a 1 gallon jug and then slowly poured it back into the radiator. I checked the hoses, both were secure, but whereas the top hose was hot, the bottom hose was cold. I assumed that the thermostat wasn't opening. I'd checked the thermostat in a pan of boiling water the previous day so I knew it was good, so I realised that it was probably still a "burping" issue.

 

 

I drove it home (it overheated again after around 20 miles) and once back home I let it cool down for a couple of hours. Once again, the overflow tank was full. I drained it again as previously described, and slowly poured it back into the radiator. I then started the car, and with the radiator cap off I continued to slowly pour water into the radiator.

 

 

There were lots of air bubbles again as I did this, but this time, the thermostat opened, and as the thermo fans came on, the coolant would suddenly drop, so I'd add more water, and the thermostat would close again. Once the coolant in the block heated up again the fans would come on, and the thermostat would open, and I could get another pint or so of water in before the thermostat closed again. This happened another few times until there was no discernable drop in coolant in the radiator, and the temp gauge needle stayed in the halfway position.

 

 

I've driven it all week in peak hour Melbourne traffic, and the needle hasn't moved past the halfway mark, so I'm confident that it's now fixed. It was very frustrating though, and each time I "burped" the system, I was sure that I had all the air out, but until that bottom hose got hot, I hadn't.

 

 

Re: your leak around the hose, the hose fittings on my radiator (and yours, I presume) are plastic, and a PO destroyed the fitting for my top hose by over-tightening the clamp. I've bought a new radiator which I'll be installing this weekend as I'm not confidant that my top hose is as secure as it could be, on the broken remains of the fitting. I bought mine on eBay for $100.00 including delivery, so I'm betting you can get a new one (if needed, of course) for less money in the US. Cheers, Terry.

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i'm beginning to think it is the top rad hose, not the overflow hose.

i have never seen an overflow hose with a clamp.

 

but you are right, replace the hose.

This is what I'm looking at. Let me know if this video works for you:

https://www.dropbox.com/s/f83x6epb25j9sz5/2013-08-22%2014.17.22.mov

 

And thanks for your help, everyone. I'm really holding out hope that the HG are not the problem. I'm going to replace the hose and radiator cap (you recommend a Subaru cap even though the radiator came from some random shop in FL?).

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the 2.5 engine is notorius for any coolant change/radiator change leaving air in the system. The air pocket heats up & H.G. leak... the "burping" is incredibly important but not as easy as other cars due to the system's design... get the air out.

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Pull that hose off and trim off the cracked end. Should be fine after that.

Remove the radiator cap and check that the inner washer is clean and the seat for the cap inside the filler neck is clean.

If the washer is cut or split the cap will not hold pressure and needs to be replaced.

It may be a good idea to just replace the cap anyway.

 

Also, when filling the cooling system the engine block has to be filled with coolant through the upper radiator hose before filling the radiator. This will minimize the amount of air in the cooling system and prevent overheating due to low coolant level.

Edited by Fairtax4me
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  • 1 month later...

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