Overheating, what makes a Subaru a Subaru! But hopefully it's just the radiator cap

[Trav]

Exactly. The way I understand it Subaru had a campaign years ago to add them to cars that didnt have them prior to the factory installing them. Changing the coolant at a minimum at manufacture specified interval or if voltage of the coolant approaches 0.2v. max. Always pop the block drain and use only citric acid only if the system is nasty otherwise use no cleaners.
DVOM set to min DC volts neg to neg battery terminal + to coolant in the radiator.

Edit: This is applicable to all alloy engines.

 

[Rand]

I was unable to watch that .. the beard is over the top.
along with the camera angle highlighting the interior of the nostrils.

 

[nthach]

Trav, I'm intrigued - please explain why poor grounding can cause HG failure. Electrolysis leading to deterioration of the metallic elements in the gasket or the sealing surface of the head? Thanks.

Electrolysis in general can ruin a cooling system - via pitting and when the coolant goes acidic(paradoxically the organic acid components in modern coolant be it sebacate, benzoate or hexanoate work by passivating ferrous metals or aluminum, older silicated green coolant used silicate to protect against cavitation, while the phosphate helped protect aluminum), the coolant becomes an electrolyte. With bad grounds, the whole engine with dissimilar metals acting as the cathode and anode becomes a battery - remember the lemon experiment in grade school?

 

[Trav]

We have all probably seen this and just didn't realize what we are looking at. Aluminum hose nipples that get corroded that are sealed behind the clamp is one example.

 

[Silver]

+1 to the bad news about head gaskets. Overheating increases the chance of them needing replacement. As you replenish the coolant, Subaru has a conditioner you can add. If the head gaskets are bad, the conditioner won't fix them, but it can't hurt and might postpone the inevitable.

I wonder what that conditioner is all about.

 

[nthach]

I wonder what that conditioner is all about.

It’s rebottled Holts(Prestone owns them) Radweld to seal micro leaks in the head gaskets. It’s similar but not a one-for-one copy of Bar’s Leak.

 

[SwampSurvivor]

Exactly. The way I understand it Subaru had a campaign years ago to add them to cars that didnt have them prior to the factory installing them. Changing the coolant at a minimum at manufacture specified interval or if voltage of the coolant approaches 0.2v. max. Always pop the block drain and use only citric acid only if the system is nasty otherwise use no cleaners.
DVOM set to min DC volts neg to neg battery terminal + to coolant in the radiator.

Edit: This is applicable to all alloy engines.

Just like a lot of folks with GM and Dexcool ... If you change the coolany frequently, it doesn't eat the gaskets out of the engine!

Unfortunately people change their oil every 3000 miles and ignore every other fluid in the car.

 

[The Critic]

Unfortunately people change their oil every 3000 miles and ignore every other fluid in the car.

If they only plan to keep the car to 150K, that is totally fine.

 

[nthach]

Just like a lot of folks with GM and Dexcool ... If you change the coolany frequently, it doesn't eat the gaskets out of the engine!

Unfortunately people change their oil every 3000 miles and ignore every other fluid in the car.

The Dex-Cool problems were IMO was mostly due to GM doing an “drop-in” replacement with older engines(the 3.1/3.4 “High Value” V6, 3800 and the Vortec 4.3/5.7/7.4) on the assembly line. The Northstar V8(that eats head gaskets for a different reason), the Saturn 4s, the 2.2L I4 in the J-Body Cavalier/Sunfire as well as the new at the time Ecotec 4 had little issues on Dex-Cool. The older engines needed a hastily-designed gasket.

The theory of air degrading Dex-Cool is a myth too. The LSx-based vans still had open coolant surge/overflow tanks.

 

[Wheel]

I wonder what that conditioner is all about.

If I remember correctly, the conditioner was aimed at the 2nd gen 2.5 ej engines which tended to leak coolant externally from the head gaskets. The 1st gen ones leaked from combustion to coolant, usually blowing coolant out thru the overflow tank. The last of the ej series 2.5 had a tendency to leak oil externally at the head gaskets, but this could easily leak into the coolant if ignored long enough. I've had the joy of a 1st and 3rd gen fail, and my Dad got the 2nd gen leak. This shouldn't be this hard to have done right the first time. Most of the turbo engines don't have this particular fail.
You can get a kit to test for exhaust gasses in the coolant, some garages may have it on hand. The 'conditioner' is unlikely to resolve that particular issue.

 

[nthach]

You can get a kit to test for exhaust gasses in the coolant, some garages may have it on hand. The 'conditioner' is unlikely to resolve that particular issue.

HF has those kits as well.

 

[slacktide_bitog]

I found this video of someone using the Blue Devil Pour and Go on a 98 Forester EJ25D. It was one of the candidates ChrisFx considered using, and it's also used in the exact same car and engine I have. The EJ25D was only used for 98; Subaru switched to the SOHC EJ251 for 99.

Also, the Blue Devil comes in a small bottle that you use all of, which is better than buying a big bottle to only use half. However, the Bars Leaks has a $10 rebate, making it cheaper than the Blue Devil

 

[slacktide_bitog]

Update

The radiator cap is still cold, but the lower radiator hose does get warm. No more overheating so far

 

[slacktide_bitog]

Another update

The radiator cap is still cold, but the upper radiator hose gets hot, and the lower hose gets warm.

 

[Sayjac]

The theory of air degrading Dex-Cool is a myth too....

This opinion ignores that air in the GM cooling system was just one factor in the failure of systems using DexCool. Speaking from personal experience with a 3800 engine, the radiator angle neck fill hole combined with the unpressurized recovery tank, made it virtually impossible to fill the radiator to the top. Whether it was the air in the system or the fact that the radiator couldn't be filled to the top, the result was the same. Add in the cheap manifold gaskets combined with DexCool's plasticizer attributes, and it was a now proven recipe for the failures seen in those GM cooling systems.

 

[Jake_J]

This opinion ignores that air in the GM cooling system was just one factor in the failure of systems using DexCool. Speaking from personal experience with a 3800 engine, the radiator angle neck fill hole combined with the unpressurized recovery tank, made it virtually impossible to fill the radiator to the top. Whether it was the air in the system or the fact that the radiator couldn't be filled to the top, the result was the same. Add in the cheap manifold gaskets combined with DexCool's plasticizer attributes, and it was a now proven recipe for the failures seen in those GM cooling systems.

A little bit of air at the top of the radiator won't cause the engine to overheat or anything else catastrophic. At worst at little air can cause you to loose heating if the air is trapped in the heater core. Dex-cool is a perfectly good coolant, and it's much hyped and feared platicizer abilities are a bunch of hot air as the popular alternative used in the Asian coolants is also an platicizer. The blame rests squarely on the shoulders of the garbage gaskets that GM switched to on the 3800's that failed regardless of the coolant type you used. It's a well known fact that GM switched to Dex-cool after the introduction of the new junk gaskets and the 3800's that left the factory with the old green coolant failed just as often as the cars that came after them with Dex-cool.

 

[Sayjac]

^^^While some or rather one 'afaik' OEM Asian AF may use an inhibitor labeled as "plasticizer", zero OEM Asian Phoat AFs use 2eha as inhibitor in their formula. The same goes ALL the true Asian aftermarket AFs (e.g. ZAV, Peak OET). As for sebacate used by Toyota, apparently they made a conscious decision to use it and 'not' 2eha. One could infer Toyota found it to be far less aggressive than 2eha. Whatever the reason, Toyota still maintains the no 2eha as inhibitor for OEM Asian AFs profile and it's worked for them. Even the member commenting this thread on GM air in system, when it came time to choose between a true Asian Phoat AF and current Prestone with 2eha, chose the former as explained HERE. This much certain, as long as the OEM Asian AFs avoid use of 2eha, no vehicle I maintain calling for Asian Phoat as spec will see an AF using 2eha.

It would be interesting to see an 'authoritative' citing/citings, study/studies proving as posited, that GM cooling systems using original green AF failed at the same rate as those using DexCool. That said and said before, I've got no problem with DexCool in modern cooling systems that now spec it as their AF. In other words, cooling systems now designed for its use.

Back to topic, I agree with the comment(s) suggesting use a coolant combustion gas test(er) to see if head gasket is the issue.

 

[bullwinkle]

The Dex-Cool problems were IMO was mostly due to GM doing an “drop-in” replacement with older engines(the 3.1/3.4 “High Value” V6, 3800 and the Vortec 4.3/5.7/7.4) on the assembly line. The Northstar V8(that eats head gaskets for a different reason), the Saturn 4s, the 2.2L I4 in the J-Body Cavalier/Sunfire as well as the new at the time Ecotec 4 had little issues on Dex-Cool. The older engines needed a hastily-designed gasket.

The theory of air degrading Dex-Cool is a myth too. The LSx-based vans still had open coolant surge/overflow tanks.

Dex engines WILL rust & sludge if air is trapped in the cooling system-which inevitable when GM used junk nylon LIM gaskets and PLASTIC radiator caps! When they changed the gaskets, went to a dry LIM connection (like my LS 6.0), and used a non-crap radiator cap, the Dex issues pretty much disappeared. Ford learned the same lesson with the Dex-like Specialty Orange and heater core plugging. There's MANY better alternatives if you can't engineer things correctly!

 

[bullwinkle]

Another update

The radiator cap is still cold, but the upper radiator hose gets hot, and the lower hose gets warm.

Shame it's too old for the Carvana buyers! (I know, dumping issues on a future unsuspecting buyer!)

 

[nthach]

^^^While some or rather one 'afaik' OEM Asian AF may use an inhibitor labeled as "plasticizer", zero OEM Asian Phoat AFs use 2eha as inhibitor in their formula. The same goes ALL the true Asian aftermarket AFs (e.g. ZAV, Peak OET). As for sebacate used by Toyota, apparently they made a conscious decision to use it and 'not' 2eha. One could infer Toyota found it to be far less aggressive than 2eha. Whatever the reason, Toyota still maintains the no 2eha as inhibitor for OEM Asian AFs profile and it's worked for them. Even the member commenting this thread on GM air in system, when it came time to choose between a true Asian Phoat AF and current Prestone with 2eha, chose the former as explained HERE. This much certain, as long as the OEM Asian AFs avoid use of 2eha, no vehicle I maintain calling for Asian Phoat as spec will see an AF using 2eha.

It would be interesting to see an 'authoritative' citing/citings, study/studies proving as posited, that GM cooling systems using original green AF failed at the same rate as those using DexCool. That said and said before, I've got no problem with DexCool in modern cooling systems that now spec it as their AF. In other words, cooling systems now designed for its use.

Back to topic, I agree with the comment(s) suggesting use a coolant combustion gas test(er) to see if head gasket is the issue.

If Toyota pink, which uses sebacate as the organic acid wasn’t as “aggressive” as 2-EHA, millions of 1MZ/3MZ/2GR V6s and the UR-series V8s wouldn’t leak coolant from the valley plate or the timing cover/water pump junction.