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I did my HGs myself about 20k mi ago and haven't had any issues until recently. I have done EA81, EJ255, EJ25D HGs before and didn't have any problems with them. I however used the Fel-Pro gaskets on this car. Hopefully that won't come back to bite me??

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3 hours ago, 1197sts said:

The headgaskets have been replaced, I did them myself with OEM MLS gaskets they have about 45K since it was done. I have done lots of them with no failures but this could be the first. I'm curious, is there a reason they're prone to this kind of problem after HG have already been replaced? Thanks.


 

 

I like data. Being around hundreds of EJ25s over long periods of makes it incredibly obvious as a fact that replacement headgaskets have higher rates of additional failure modes.

Discussing why ends up in dreadfully anecdotal opinions which I can’t stand, or long winded nuances of what exactly we are talking about to make any real progress - history of decades old vehicles, prior ownership, repair choices, and then design elements. I find that efficacy of that limited and too filled with anecdotal commentary.

But I would start the conversation by qualifying what we are comparing:

1. Newly cast materials that have never been heat cycled being assembled by robotic instruments calibrated on tight schedules in near clean room environments developed by QC driven departments focusing on 6 sigma, ISO 9001 (which in some ways don’t really mean anything sometimes but as an illustration it still stands)

And:

2. Decades old heat cycled multi owner unknown history and maintenance materials being assembled with facilities and tools that are unlikely to be as good, accurate, clean, well maintained and calibrated as the former. 

Edited by idosubaru
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1 hour ago, tylertrend said:

I did my HGs myself about 20k mi ago and haven't had any issues until recently. I have done EA81, EJ255, EJ25D HGs before and didn't have any problems with them. I however used the Fel-Pro gaskets on this car. Hopefully that won't come back to bite me??

I use OEM, but have used them a couple of time and i would use them again if there was a reason too. there are shops that have installed gobs of them on EJ25s over the decades without issues. 

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3 hours ago, 1197sts said:

The headgaskets have been replaced, I did them myself with OEM MLS gaskets they have about 45K since it was done. I have done lots of them with no failures but this could be the first. I'm curious, is there a reason they're prone to this kind of problem after HG have already been replaced? Thanks.

 

Load dependent is classic sign of clogged radiator. Make sure it flows great with no resistance.  It should flow all the water supply of a standard well pressurized 45psi home hose.  If you have a well or long runs or otherwise weak volume it may not be a good test. 
 

It is not the most common scenario, But I’ve seen replaced EJ25s do the same.  Pretty common for them to only do it under load for a few months.  Get slowly progressively worse - they’ll exhibit overheating at lesser loads over time and then water loss from internal consumption.  issues get worse quicker over time.

If you’re that confident in your HGs then just focus on the radiator since you already have classic clogged rad signs. 

Edited by idosubaru
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I am wondering if it would be a good test to remove the Thermostat and see if that fixes things. Would indicate if combustion gasses are getting in and messing with the T-stat or if the rad can't dissipate the heat anymore. I may try that tomorrow while I'm fixing the coolant leak that my GLF sprung right when I got home tonight (cut in heater core hose over a worm clamp).

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I just started having this same problem myself on my 2009 Forester X Limited non-turbo. There is bubbling in the radiator overflow tank and the fluid never gets sucked back into the radiator like it should. After the engine cools down (overnight), when I open the radiator can I can hear a bit of a suction. When I rebuilt it in 2018, I used FelPro gaskets and seals (including HG). I've burped the radiator twice after I just replaced the water pump, thermostat and both radiator fans. I have an uneasy suspicion that my HG is failing but I wanted to see if there is anything else that could cause this. If it does turn out to be the HG, I will pull my engine again and replace them. Thank you in advance for your help on this.

Edited by Monacle-Pete
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8 hours ago, tylertrend said:

I am wondering if it would be a good test to remove the Thermostat and see if that fixes things. Would indicate if combustion gasses are getting in and messing with the T-stat or if the rad can't dissipate the heat anymore. I may try that tomorrow while I'm fixing the coolant leak that my GLF sprung right when I got home tonight (cut in heater core hose over a worm clamp).

You have to gut the tstat since the outer circumference holds the gasket in place for sealing the housing. It's easy to rule out everything else but HG's and radiator.  And those two are not hard to differentiate so I wouldn't go through the effort. 

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59 minutes ago, Monacle-Pete said:

I just started having this same problem myself on my 2009 Forester X Limited non-turbo. There is bubbling in the radiator overflow tank and the fluid never gets sucked back into the radiator like it should. After the engine cools down (overnight), when I open the radiator can I can hear a bit of a suction. When I rebuilt it in 2018, I used FelPro gaskets and seals (including HG). I've burped the radiator twice after I just replaced the water pump, thermostat and both radiator fans. I have an uneasy suspicion that my HG is failing but I wanted to see if there is anything else that could cause this. If it does turn out to be the HG, I will pull my engine again and replace them. Thank you in advance for your help on this.

Headgaskets.  Resurface the heads and make sure all the head bolts and head bolt holes are clean and lubricated during assembly. 

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1 hour ago, idosubaru said:

You have to gut the tstat since the outer circumference holds the gasket in place for sealing the housing. It's easy to rule out everything else but HG's and radiator.  And those two are not hard to differentiate so I wouldn't go through the effort. 

Well since my overheating only happens under highway load, in the heat of the day, no oil/coolant mixing, no white smoke, and perhaps a small amount of arrogance that I did the HG job properly so they shouldn't be a problem points me towards the radiator. It's 16 years old/ 188K and the original unit. The one on my '99 OB literally cracked apart when I was out of state traveling when it was 18 years old so maybe it's just time.

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Interesting observation as I was out doing another bleeding of the system. There are a lot of small chunks that look like graphite and are very soft. I was able to get a couple large ones and smear them on the funnel and they are full of a brass looking flake, I can see it pooling on the bottom of the filler neck too. Maybe old deposits from a HG problem years back? I never did a complete "flush" of the system when I did them. Maybe the rad is plugged up with this stuff. Curious about where all that metallic flake is coming from.

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1 hour ago, tylertrend said:

Interesting observation as I was out doing another bleeding of the system. There are a lot of small chunks that look like graphite and are very soft. I was able to get a couple large ones and smear them on the funnel and they are full of a brass looking flake, I can see it pooling on the bottom of the filler neck too. Maybe old deposits from a HG problem years back? I never did a complete "flush" of the system when I did them. Maybe the rad is plugged up with this stuff. Curious about where all that metallic flake is coming from.

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That doesn’t seem like great news, If it’s really bad it’s worth noting.

How did the gaskets fail the first time - what all symptoms presented ?

 

Keep in mind it’s a 16 year old overflow bottle with normal old age ambient grime on the inner walls that’s never (or once maybe) been cleaned and is now exchanging overheating coolant with the radiator daily. I would be careful to assume too much unless it’s egregious or I can see and diagnosis the car history and amount in person.

Edited by idosubaru
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8 minutes ago, idosubaru said:

That doesn’t seem like great news, If it’s really bad it’s worth noting.

How did the gaskets fail the first time - what all symptoms presented ?

 

Keep in mind it’s a 16 year old overflow bottle with normal old age ambient grime on the inner walls that’s never (or once maybe) been cleaned and is now exchanging overheating coolant with the radiator daily. I would be careful to assume too much unless it’s egregious or I can see and diagnosis the car history and amount in person.

Original HG failure was just oil leaks, Didn't run hot for me or the PO to my knowledge. I had the overflow out a few weeks ago and gave it a good scrubbing. It's this metallic flake stuff that's weird to me. I've been reading about issues with heater core blockages causing issues but this car has always, and does today, have great heat. No exceptions. The hot running didn't really start until I moved from ME to OK so maybe it just needs a good flushing and a new rad. 

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15 minutes ago, tylertrend said:

Original HG failure was just oil leaks, Didn't run hot for me or the PO to my knowledge. I had the overflow out a few weeks ago and gave it a good scrubbing. It's this metallic flake stuff that's weird to me. I've been reading about issues with heater core blockages causing issues but this car has always, and does today, have great heat. No exceptions. The hot running didn't really start until I moved from ME to OK so maybe it just needs a good flushing and a new rad. 

have you ever added Subaru coolant conditioner to this vehicle ?


Heater cores on Subaru’s can usually be ignored in situations like yours and comments about them on Subaru’s are often anecdotal, incorrect, guesses. I’m almost positive the 100 times I’ve heard “.....the heater core.....” about diagnosing a Subaru has been 100% wrong. 

There are Subaru’s, like Tribecas, with heater cores that do clog up and cause lack of heat to either the drivers or passengers side, or both. They never overheat eventhough that have egregious internal heater core degradation. 

My guess is that At most it’s a symptom of hot inconsistent coolant flow patterns and characteristics dislodging debris internally and not a clue, or hint, to causation.

Edited by idosubaru
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45 minutes ago, idosubaru said:

have you ever added Subaru coolant conditioner to this vehicle ?


Heater cores on Subaru’s can usually be ignored in situations like yours and comments about them on Subaru’s are often anecdotal, incorrect, guesses. I’m almost positive the 100 times I’ve heard “.....the heater core.....” about diagnosing a Subaru has been 100% wrong. 

There are Subaru’s, like Tribecas, with heater cores that do clog up and cause lack of heat to either the drivers or passengers side, or both. They never overheat eventhough that have egregious internal heater core degradation. 

My guess is that At most it’s a symptom of hot inconsistent coolant flow patterns and characteristics dislodging debris internally and not a clue, or hint, to causation.

I have never added coolant conditioner, but I can't speak to what the PO may have done. I can't say I saw any evidence of the stuff when I did the HGs.

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1 hour ago, tylertrend said:

I have never added coolant conditioner, but I can't speak to what the PO may have done. I can't say I saw any evidence of the stuff when I did the HGs.

Gotcha.  I don't think it matters and wouldn't cause what you're probably seeing anyway but thought it would be good to get on the table since we're in this far. Good luck!

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I just went on a test drive and it consistently runs hot under high rpm/load. On the highway, turning the heat on full brought it down to about 210F steady vs high 220's so I just ordered a new rad and will do a complete flush of everything this weekend and report back.    I checked the TB tension also and it's good and tight, just for semantics.

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22 hours ago, tylertrend said:

Interesting observation as I was out doing another bleeding of the system. There are a lot of small chunks that look like graphite and are very soft. I was able to get a couple large ones and smear them on the funnel and they are full of a brass looking flake, I can see it pooling on the bottom of the filler neck too. Maybe old deposits from a HG problem years back? I never did a complete "flush" of the system when I did them. Maybe the rad is plugged up with this stuff. Curious about where all that metallic flake is coming from.

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Those brass flakes reminds me of oldschool bars stop leak powder.  

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