Another question about antifreeze.

[efseiler]

Do the thermal expansion coefficients on various antifreezes differ greatly? 

 

What I mean is...I recently swapped out some very old original coolant in my recently acquired Forester.  Now when I take it for drives the expansion tank fills to a level much higher than originally.  When I take it for very long drives the tank fills almost all the way to the top!  Presumably this is because the mix achieves a higher temperature.  When it cools overnight the level returns to almost exactly the same place.

 

 

I'm just concerned whether putting the new antifreeze (ShellZone yellow stuff) was a good call.  It's not DexCool and I was told that mixing would be compatible.  There is no overheating but I do notice sometimes a little bubbling which occurs mainly after long, hard drives.  I don't think it's a HG because it does appear to be intermittent, perhaps due to water evaporation that may occur when the engine is really horsed.

 

 

Maybe I need to mix in more water?

 

 

Thanks for your input...

 

 

 

--Damien

[Fairtax4me]

Bubbling is a typical sign of head gasket failure.

 

Is this a DOHC or SOHC 2.5?

[Rooster2]

Bubbling is a typical sign of head gasket failure.

 

Is this a DOHC or SOHC 2.5?

The bubbles are an indication of exhaust gas entering the cooling system through a breach in the head gasket. If SOHC 2.5, this can be fixed with a special coolant additive, but I suspect you have a DOHC 2.5

[forester2002s]

I doubt that the coeff of thermal expansion changes much between different brands of antifreeze.

Could be a head-gasket leak.

Or it might just be an air-bubble in the coolant, expanding when hot, and filling the overflow bottle. Get that air-bubble out, and you may be good to go.

[mikaleda]

I would try burping the system again, it sounds like there is air in the system.

[efseiler]

I'm pretty sure it's EJ251 which is SOHC (I think).  Maybe the headgasket is leaky but it doesn't bubble all the time and there's no other symptoms of a blown one.

 

 

So you're saying it's the so-called 'external leak'?

 

 

If the HG is blown then that would explain it's very low price but maybe the seller was too sure that was the case.

[keith3267]

What ratio did you mix it.  If you used a premix, you should not add any water.  If you bought a full strength coolant, it should be mixed with distilled water at a 50/50 min to 2:1 (antifreeze : water) max concentration.  I always go with a 2:1 just to get the additional concentration of corrosion inhibitors.  You cannot use it at full strength as its freeze protection goes down above 67%.  At 100%, it still protects in a way as it does not expand when frozen like water does, so if it freezes, it won't crack the block or heads.

 

With a Subaru, you should go to the dealer and get the stopleak additive they use in the factory mix.  This is preventative maintenance, you need to use it before the head gasket fails, not after.

 

Most antifreezes are Ethylene Glycol, even Dexcool.  The difference between them is the corrosion inhibitors.  The only significantly different antifreeze are the environmentally friendly (less toxic) antifreezes that use Polypropylene Glycol as a base.  It can be used at 100% concentration, but has less freeze and overheat protection.  It is good enough for anywhere in the US except parts of Alaska.

Edited December 26, 2014 by keith3267

[efseiler]

But that stuff won't help with seepage through to the water jacket...will it?

 

What could cause occasional bubbling like that because it doesn't do it all the time...I've checked on more than dozen occasions to sure of that.

[mikaleda]

Antifreeze is made to be mixed 50/50. Adding more antifreeze to the mixture will not help and will more than likely hinder flow. Subaru does suggest using Subaru genuine coolant conditioner to help prevent external head gasket failure. Your symptoms sound like you have air trapped in the system either from head gasket failure (internal leakage) not likely with your engine or inproper burping/filling of the cooling system

Edited December 27, 2014 by mikaleda

[efseiler]

well ok...but what could be causing intermittent HG leakage?  I think it's just blowing off some steam due to evaporation (hoping I'm right).  Maybe the radiator cap is not properly sealed drawing air in.

 

They way those engines are designed and the way they aspirate probably affect how they disperse heat.  It goes against conventional thinking but such phenomena are entirely possible because water can and does exist in all three phases simultaneously. 

 

It doesn't leak a drop of oil...it doesn't leak a drop of coolant.  The OF tank is squeaky-clean.

 

Go figure!

 

--Damien

[mikaleda]

Antifreeze bonds with water and raises the boiling temp. If your antifreeze is boiling you are needing a stronger mix, a good antifreeze tester would be good here. Your cap isn't going to cause air to be sucked in while your driving. An intermirent hg leak is quite common, that is how mine went. It would run fine till I went to drive it long distances then the head gasket would start to seep. My thought on this is thermal expansion, as the engine gets properly warmed up the metal gets up to temp compleatly and when you give it a little more gas the gasket starts leaking.

Personally its worth the money for the block test to be absolutly sure what is going on. Especially if your positive you got all the air out of the system when you filled it.

There is no additive that will stop an internal leak on a Subaru hg failure, the only thing these will accomplish is the clogging of the heater core

Use OEM headgaskets only on the 2.5l, would be good to replace the timing belt, idlers, and water pump while your there.

I hope its not a head gasket failure, they really suck.

[keith3267]

Ethylene Glycol Antifreeze is made to be mixed with water.  It is not made to be mixed at 50/50.  It is made to be mixed at anywhere from 30% to 70% concentration, but the peak effectiveness occurs at 67%.  That is where the mix has the highest boiling point and the lowest freeze point, and 67% does not hinder flow.

 

50/50 is the concentration that works for most of the lower 40.  It is good down to -34F.  In very hot climates, there seems to be some question about whether mixes higher than 50% carry as much heat, therefore are not as effective as the higher mix concentrations, but I have used 67% concentrations for about 40 years in very hot climates, including pulling the grade out of Death Valley into California (in my Saturn) on one of its hottest days on record, and did not have an issue.  I even had the AC on at the time.

 

Right now my Subaru has the factory fill in it which is 50%, but if I ever change it, it will be to the 67% concentration level.

Edited December 27, 2014 by keith3267

[mikaleda]

Ethylene Glycol Antifreeze is made to be mixed with water. It is not made to be mixed at 50/50. It is made to be mixed at anywhere from 30% to 70% concentration, but the peak effectiveness occurs at 67%. That is where the mix has the highest boiling point and the lowest freeze point, and 67% does not hinder flow.

 

50/50 is the concentration that works for most of the lower 40. It is good down to -34F. In very hot climates, there seems to be some question about whether mixes higher than 50% carry as much heat, therefore are not as effective as the higher mix concentrations, but I have used 67% concentrations for about 40 years in very hot climates, including pulling the grade out of Death Valley into California (in my Saturn) on one of its hottest days on record, and did not have an issue. I even had the AC on at the time.

 

Right now my Subaru has the factory fill in it which is 50%, but if I ever change it, it will be to the 67% concentration level.

You need to state fact not opinion. Antifreeze is made to be combined 50/50

When I use this mixture with low silicate green antifreeze it tests good to -45.

Antifreeze raises boiling point, lowers freezing point and lubricates water pump and keeps corrosion down in thesystem.

[efseiler]

Oh I didn't know it also raised the boiling point. 

 

 

Well there's a mix of OEM Subaru green and yellow stuff in there now.  Clearly the two are different and they share different physical characteristics. I was amazed at how much the yellow stuff would expand into the tank.

 

 

If corrosion on those gaskets is a problem thermal characteristics could play a key role.  The right mixture of coolant could draw heat from the cylinder walls and reduce entropy like that.

 

 

Anyway I'm bracing myself for the bad news cuz...I could hardly believe the low sale price!  It's a nice car tho...now the chiggers and mosquitos leave me alone...  Sounds a little bit like a diesel, too...maybe the compression ratio in there is a little higher than on other similar engines.  I bet that's also part of the reason why those gaskets blow, as well.

 

 

 

Imagine putting d2o instead of h2o in your radiator!

 

 

Cheers!

 

--Damien

 

p.s.  Slaves ain't cheep!

 

 

 

 

 

 

[papajam]

You need to state fact not opinion. Antifreeze is made to be combined 50/50

 

I think you may be confusing full strength antifreeze/coolant with the plethor of 50/50 pre-mixes that are available. Neither the Prestone, Valvoline (Zerex/DexCool), Peak or Dow Chemical websites say anything about their products being made to be mixed 50/50. On the contrary actually. All give a range of percent concentrations that can be used to obtain the end users freeze and boilover protection requirements.

But, it is obvious that my quick search did not reveal a manufacturer whose product is made to be combined 50/50. Please provide a link(s) to a product(s) that is made to be combined 50/50.

[idosubaru]

If it's a SOHC (99 or up forester) then more than likely the headgaskets were already replaced with low grade gaskets and/or head not resurfaced

If it's a 1998 then it's DOHC and this is typical headgasket symptoms - very common, classic symptoms. 

 

This is not an external failure - it's internal. The exhaust gases are pushing past one of the lower fire rings into a lower coolant passage, coolant pushing into overflow, is typical internal headgasket failure.

 

that it happens randomly is also typical of internal failures. they can go a year or more between repeat failures. i guess a brief overview woudl be to say the expansion exposes the gasket breech only at certain specific conditions (long hard drives for example).

 

98 forester has the DOHC phase I.  99+ has SOHC Phase II. 

 

SOHC's dont' generally fail internally unless the headgaskets have already been replaced.  you can peak at the head/block interface and likely tell the gaskets have been replaced and are not MLS.  so that's why i said at the beginning the heads have likely been removed before. 

 

repair:

1.  use Subaru Turbo EJ25 (if 99 and up SOHC) head gaskets or Six Star

2.  resurface the heads

[keith3267]

To answer your original question, the answer is no.  There is something else at play here.  Changing your coolant should not cause a blown HG, if that happened, it would be just a coincidence.  Did you change the concentration of the mix?  That might have an effect on the expansion.  Was the new antifreeze a premix or full strength, and if it was full strength, did you mix in some water (preferably distilled) so that the concentration is somewhere between 30 and 70%?

 

Did you drain the block and radiator or only the radiator?

Edited December 28, 2014 by keith3267

[mikaleda]

I think you may be confusing full strength antifreeze/coolant with the plethor of 50/50 pre-mixes that are available. Neither the Prestone, Valvoline (Zerex/DexCool), Peak or Dow Chemical websites say anything about their products being made to be mixed 50/50. On the contrary actually. All give a range of percent concentrations that can be used to obtain the end users freeze and boilover protection requirements.

But, it is obvious that my quick search did not reveal a manufacturer whose product is made to be combined 50/50. Please provide a link(s) to a product(s) that is made to be combined 50/50.

I never buy premixed, ever. I don't like paying for water. I have always been told to run 50/50 and have never had any issues with freezing or boiling at this mix. Reading the back of the bottle I do see mix strength chart and do see what you are talking about, but I do see five steps that most people will read

 

1. Drain cooling system, and flush with plain water

2.let system cool and drain

3.check owners Manuel for system capacity and fill system to achieve a 50/50 antifreeze/water ratio

4. Run engine 10 minuets with heater on high, let coo and check coolant leval

Oh and step five

5. Check resivour and radiator levels and top off with a 50/50 mix of same brand antifreeze

 

These are the instructions on the back of Napa extended life antifreeze

Edited December 28, 2014 by mikaleda

[efseiler]

Its an '01 EJ251 which supposedly has the redesigned gaskets. 

 

Well I took it out on the highway today for a 30 mile stretch from a cold start...it was interesting because the temp gauge didn't rise to its usual level.  When I parked it, got out and looked in the OF tank it was bubbling out some kind of gas so I though d***...I'm screwed again.   But the interesting thing what that the coolant level was much lower than normal (usually when it is fully warm it rises to a level much higher in the tank).

 

 

So I drove it back home and this time on the highway I really gunned it...but when I got back and inspected the tank again there was no sign of bubbling and no residual bubbles at all indicating that the bubbling had stopped somewhere on the trip back.  My guess (no pun intended     ) is that perhaps the gas that gets trapped in there is water vapor anyway and pushes more coolant than normal into the OF tank.  Some sort of 'vapor lock' perhaps within the radiator.  I think that because if it were exhaust gas in there the OF tank level wouldn't return the the usual level when it cools as it always had. 

 

Maybe those engines generate enough heat to cause boiling within the water jackets (which I suppose could be bad anyway).  It didn't smell like HC in there anyway and the tank is squeaky clean.

 

That why I asked about the coolant mix because if it's boiling in there I want to eliminate that so the vapor doesn't lead to cooling irregularities which would in turn cause shear stresses and strains that would completely cause a block failure.

 

I drained the radiator once (which had the original Subaru green stuff) and filled it with 50/50 ShellZone yellow stuff.  I figured it would be a good idea cause what was in there didn't seem like it had been changed once since the life of the vehicle (and it's pushing 135K miles).  I heard that the so-called Subaru green has a special formulation but there seemed to be some skepticism about that claim.

 

 

 

Perhaps that's normal operation because most people don't notice anything is wrong until it really blows up!

[mikaleda]

Sounds like you released the air bubble in the system, your probably fine now.

[keith3267]

I know this will start an argument, but here goes.  If you have an operating cooling system and have followed the recommended maintenance schedule, then never, never, never:

 

1. Flush the cooling system with plain water

 

2. Flush the cooling system with a chemical flush

 

3. Flush the cooling system with a power flush machine.

 

All the above will only contaminate the cooling system and lead to early failure.  You can never get all of the fresh water or other chemicals out of the engine, some will always be trapped.  The minerals found in tap water will immediately start consuming some of the corrosion inhibitors in the fresh antifreeze.  Chemical flushes are hard on seals and no matter haw much fresh water you pour through the system after, there will always be some residual chemical left behind.

 

Power flush machines use a reservoir of coolant that can be of unknown origin.  Your old coolant will get into the reservoir along with the used coolant of other vehicles.  It is supposedly filtered somehow to make it good, and that may have worked back in the day when all antifreezes were the same, but not today.

 

Power flushes and chemical flushes should only be a last ditch effort to save a neglected and non functioning cooling system.  They may not work, but they are usually not too expensive so its a risk/reward decision.

 

Drain the radiator and the block.  Refill with the desired mix of antifreeze and distilled (or purified or demineralized) water.  Follow the recommended maintenance schedule.  For Subaru's, do put in the additive called for.

 

One last thing, my understanding is that Peak antifreeze is the only antifreeze that meets the Japanese spec that Subaru's use, but in my opinion, any major brand, longlife, universal (HOAT or G06) antifreeze changed every 5 years will do just as well.

Edited December 29, 2014 by keith3267

[mikaleda]

I'm fairly sure they tell you to flush with plain water just to get any other type of coolant out of the system so they don't mix and cause issues.

I'm not saying that flushing the system with plain water is correct and that's not how I flush a system, I was just stating what was written on the bottle.

 

You are just trying to start an argument and I am not going to satisfy you. No matter what I say your going to insist that im wrong and your right. All I'm saying is I've always used green antifreeze mixed 50/50 and have never had issues. When I flush a car I use the chemical flush and then afterwards I use water pump lubricant and new antufreeze , I've never had an issue doing it this way.

 

I have worked on cars from 67 to 2011 model years and unless they specifically state to use a certain brand/mixture of coolant I use green low silicate antifreeze mixed 50/50. I have never had any issues doing this period.

Edited December 29, 2014 by mikaleda

[keith3267]

My goal was not to start an argument, but often when I say anything against flushing the cooling system, someone will take the opposite stance.   Flushing with tap water just to prevent mixing is not valid.  That would be like hosing out your crankcase every time you change the oil so the different brands don't mix.

 

The only issue with mixing types of antifreeze was with dexcool and the old high silicate formula antifreeze.  I don't know if that old stuff is even on the market anymore.  Dexcool is an OAT antifreeze, all others are HOAT.  HOAT is a hybrid version of the OAT type and is compatible and can be mixed together, though I personally would not do that except for the small amount left in the system when changing over from OAT to HOAT.  I have done this conversion a couple of times and have never had a problem.

 

I've been working on cars since high school, class of 67.  After about 20 years, I noticed that every time I used a chemical flush, I had problems with seals and hoses leaking within a month or two.  It was a trend.  I stopped using chemical flushes and since then, in the last 30 years, I have had very few cooling system problems.  The occasional stuck (open) thermostat, oil soaked hose that leaks or a leaking rubber seam on the new aluminum/plastic radiators and of course, the radiator cap that stops holding pressure, but no major problems.  Well one leaking waterpump but that one had 265k miles on it.

 

I do not like flushing automatic transmissions either and I get some flack over that from time to time.  The only two things I flush are brakes and toilets.

 

If anyone disagrees with me, thats OK.  You are paying for your car and I am paying for mine, so you do what you think is best and I will do what I think is best.  I will listen to your arguments for the way you do yours, but I will make mine too.  Please don't take offense, I didn't mean any.

Edited December 29, 2014 by keith3267

[efseiler]

Well I dropped by our local Subaru dealership today and picked up a bottle of...uh...medication for my Subaru.  (They only charged me $2.73 for it, too!)

 

As a final note, I think regular oil changes is also key to keeping those HGs intact, as well.  I think old oil causes a pressure buildup within the crankcase....

 

 

 

Cheers!

 

--Damien

 

p.s. If the hair on your head was a spark then your baseball cap would be like a headgasket, wouldn't it?

[efseiler]

Well so much for all my wishful thinking.

 

Now there's antifreeze in the oil so another EJ251 gonzo after 135K miles.