Coolant bubbles

[ktdenali]

and yes I have check the small hose going from the radiator to the overflow tank. It is NOT blocked. You can blow right through it.

[Fairtax4me]

The bubbles are pressure being released. Either the cooling system has a large amount of air trapped in it, it is overheating and boiling, or there is cylinder compression being pushed into the system past the head gaskets.

 

Bleed the system first. Park it with the front end uphill and run it to operating temp with the radiator cap off. If the radiator has the bleed plug on the top right side open it as well.

[ktdenali]

well it's been several weeks. the bubbles are still persistent. I drove the car over 1000 miles twice on the Beartooth Hwy going from 5000ft to 11000 elevation. the car never over heated but my overflow tank bubbles like crazy.it even pushed out some coolant through the overflow tank. At the end of a day, the overflow tank would be overly full, and the radiator low. In other words it does not suck the coolant back in the radiator like it should after it cooled down.

The mechanic who did my Head gaskets just one year ago this month has no idea what is causing it. He sees no sense in replacing the HG again 'cause it was done right in the first place. I left the car with him one over night for him to hear what it sound like on cold start (the gurgling noise). he did not hear it. I think he put some kind of powder in my coolant (I am guessing) - something lie a HG sealer. Now the bottom of my coolant in the overflow tank is full of gunk, murky. I assume it is from the stuff he put in.

 

No I have not done the hydrocarbon testing cause every mechanic i talk to in person don't think very highly of it. It there was combustion gases coming through my coolant my nose would be able to tell, as it would smell like exhaust. It doesn't.

 

I do not know what is wrong. I give up and am tempted to sell this lemon.

Any more ideas?

[Rpm90001]

I don't know what help anyone can give you here, I think you need to divorice you mechanic, or at least start seeing other people for a while. There is only a few things that cause the over flow to pressurize, if he can't figure that out with the car in front of him, I would have doubts about his ability. If the system has a air in it, he should be able to figure that one out, but I highly doubt that is the issues. I don't know what you are so afraid to take it to someone other that your trusted mechanic, you have been dealing with this for some time. You are making it way too complicated. My feeling again is with out looking at the car is, if you are getting enough pressure in the overflow to push fluid out and you are not overheating you most likely have a head gasket leaking. I don't know anything in the cooling system that can make that kind of pressure other than the combustion chamber. I can't explain why you can't smell it. Why not just take it to the dealer? They have delt with it enough, and you will have your answer. This way if the gasket is bad, you can take it up with your mechanic.

 

 

 

When your mechanic did the gaskets, did he pull the motor out of the car? Did he resurface the heads even if there was no warping?

 

-I am not loosing any coolant. You may not get a coolent loss

-I have no exhaust smell in my coolant. Can't explain this one.

-my exhaust has no coolant smell. Unless coolent is getting pulled in the cylinder you won't.

-no overheating. It may not always cause over heating depending on the condition of the system

-no coolant in my oil or vise verse. Again... You may not get either one.

 

You have to remember, if there is a leak between the combustion chamber and any coolant passage only, high pressure from the the cylinder on the compression stroke will push exhaust through the leak into the coolant system thus pressurizing the system and pushing air/coolant in to the over flow. Just like putting a straw into a glass of soda and blowing. This type of leak may not show a coolant loss, will not put make your exhaust smell, will not get coolant in the oil or oil in the coolant. And if your system radiator and the rest of the cooling system is good you may not get over heating. You should still smell it in the overflow...can't explain that.

 

Do your self a favor take it to a Subaru mechanic and be done with it

 

Also, highly agree with "the dude's" posts.

 

People here have given good advice, but does not seem like you are taking it. you can be a good mechanic and still have a repair fail. Look how many people have done theirs more than once. You see a lot of HG repairs fail from the dealer, I believe that is because they will not remove the motor to do the HG very hard to clean the surfaced correctly and torque correctly in the car. All it takes Is a gouge in the surface, small piece if missed gasket, even a small piece of dirt to cause it to fail.

 

Here is a post I was reading and though of you. http://www.subaruforester.org/vbulletin/f88/big-bubbles-radiator-overflowing-coolant-40835/

 

One last thing.. You say 3 good mechanics looked at it, and said it's not the head gasket. If they can tell by looking at it, if they are so good...why can't they tell you what the problem is?

Edited July 9, 2011 by Rpm90001

[The Dude]

1. You don't want to do a DEFINITIVE exhaust gas test

2. You don't want to "upset" your mechanic by asking him if geniune Subaru head gaskets were used in the repair.

 

Who the heck can possibly help you with all these strange restrictions that you have placed on yourself?

 

You have "sat on your rights", anyway. It doesn't sound like your mechanic is very interested in redoing your head gaskets even if the exhaust gas test came back positive.

 

You very possibly got a bum head gasket job. You don't want do an exhaust gas test. You don't want to "upset" your mechanic. And it really doesn't matter, because after one year it's too late to do anything about it anyway.

 

If I found a mechanic putting an unknown powder in my car's cooling system without my permission, it might possibly result in a pool of blood on the shop floor. But that's me.

 

Given your self imposed restrictions, what can you do? Continue driving the car while keeping an eye on the coolant level. Once the head gasket blows completely your engine will overheat and you will be able to diagnose blown head gaskets without having done an exhaust gas test. You might have warped the heads. You might have toasted the main bearings. You very well might be stranded on the road and need an expensive tow. You will be towed to a shop, where given your situation, they will pretty much have you by the tender parts. Hopefully, you are towed to an honest shop. One that uses genuine Subaru head gaskets.

 

But you will have your diagnosis without having done an exhaust gas test. Good luck.

Edited July 9, 2011 by The Dude

[ktdenali]

Thanks for all your valuable advice. Even though I have no idea who you are and this is just a virtual conversation what I hear sound right to my ears.

 

You are right my mechanic does not seem to wanna do it over again.

I asked him if he used genuine Subaru head gaskets and he said yes, it the same kind he has been using for over 7 years.

 

I know they pulled my engine out of the car, and that is how they did it. The heads went to a machine shop and got resurfaced. So everything sound and seem right, just like what other mechanics would do. One mechanic I talked said they should have used brand new head bolts as well, and I asked bout that. they did not, and did not think that was a good idea. "My" mechanic speculated that just because the head get resurfaced the block itself may not have a perfect surface or it is warped. we do not know that. It has never over heated since I had it, which is 2 years and 25,000 miles.

 

I guess my biggest issue is dishing out another $1100 for an HG job. I thought that was done a year ago. I have a really hard time spending more money on this $5000 car. That is my biggest hurdle to jump.

 

As far as the powder, and the blood on the floor. I don't think we think alike at all.

[samneric]

Yup this sounds like a psychological issue rather than mechanical.

 

I think you know the answer to your questions but as you are slowly admitting to yourself - you don't want to deal with said answer.

 

At the end of the day - you are going to have to make a decision.

 

The options you have to choose from in my mind are:

 

A) Confront the mechanic with the results of a test. Make a deal with him to repair again or whatever.

Sell the car

C) Keep driving the car until it starts overheating badly then sell/junk it.

 

Steve

[ktdenali]

thanks Steve!

 

Those are the three options I have been thinking about as well. Selling it would be hard as it is not 100% and I do not want to lie.

I have no problem confronting the mechanic, if I have bad test results.

Running it to death is also an option but not the best of them.

 

My next question is. If my mechanic offers to do it all over again, whether it's free of charge of costly, will it fix it? What are some thought on that?

Thanks

[ktdenali]

so I am a psychological wreck....... thanks!:-\

[samneric]

so I am a psychological wreck....... thanks!:-\

 

Lol - the psych part is the hardest part afterall - the mechanical stuff is easy

 

Selling the car - You are selling an old car! You don't have to mention the *theories* of what is going on - only the facts - if that. Look at the positives of the car - apart from a few bubbles in the overflow tank the car's great right? It hasn't even over heated yet - that will come in time and only on long journeys. It just happened to me - my 98 OBW ran fine for 6 months around the city but just took it on a road trip and it overheated. At the end of the day, a fresh owner may feel better about investing in a HG job after he has driven it for a while and come to the conclusion that the HGs are the problem.

 

Fixing the car - That's a poser - there is an area of the "unkown" there. Did he use the right gaskets? did he torque the bolts down right? was the block warped? You do have to realise - even a great, experienced mechanic can mess up.

 

If it came to tearing the heads off again, I would definately have the block surface checked - it seems that was the only thing that wasn't done the first time.

 

I'm not the most mechanically knowledgeable when it goes this deep - I'm going to do the HGs on my OBW and am only going to follow the great advice on this board. If it comes to pass that my block is warped - I'm not going to know that but if I get the same symptoms after all the other things have been done, I'm going to suspect that.

 

Its a tricky dilema, I'll admit - one only made worse by not being able to do the work yourself - its always better peace of mind that way - if you do it wrong yourself its easier to blame yourself

 

Anyway, good luck with the decision making

 

Steve

[Fairtax4me]

I saw mention of head bolts. While Subaru does not require replacement of the head bolts during installation of a cylinder head, they do recommend tapping the threads of the bolts and the threads inside the block to prevent the bolts from sticking and giving inaccurate torque readings.

The block surface is rarely machined during head gasket replacement. It can lead to future failures, but the chances are slim. There are many causes for repeat head gasket failures, improper cleaning, improper torque, poor quality gaskets. Warped block surface is pretty low on the list of probabilities.

 

Will replacing the gaskets a second time fix the problem? Only if the job is done properly and all steps taken to ensure proper form of the gasket to the cylinder head and block surfaces.

 

If you don't want to spend the money to fix it, your next best option is an engine swap, which means spending money on it. Selling it in that condition would get you maybe $1000 - $1500 depending on the market in your area.

[Rpm90001]

This info came from tegger.com I believe in another post you changed the T stat and cap wit OEM. If you are sure there is no air in the system I just don't have any idea accept failed HG. Sorry so long..I ran across this on a Honda forum...credit to them, sorry so long. Not all applys to your problem, but still a good read.

 

Bubbles in coolant expansion reservoir

back to top

 

Bad radiator cap

Failed head gasket

Failed water pump seal admitting air from suction side

 

 

Air in radiator, but expansion reservoir full

back to top

 

Coolant leak

Too much air in system after fluid change

Bad radiator cap

Bad seal between radiator cap and expansion reservoir

Failed head gasket

 

 

 

Low coolant level

 

Can be caused by many, many things. Among them,

Failed head gasket

Worn water pump seals

Lack of maintenance

Hoses leaking

Radiator core leaking

Radiator upper tank cracked

If the coolant is allowed to get low, the water pump can't circulate it through the radiator at idle, so heat cannot be removed. Normally the pump can circulate even low coolant if the pump spins fast enough, so a low coolant level generally will not cause overheating at speed.

 

If the low coolant level is accompanied by an expansion reservoir level that's much higher than normal, your rad cap or head gasket is suspect.

 

Age, or the use of inexpensive silicated coolants will wear the water pump seals rapidly, causing premature leakage.

 

The water pump has a small "weep hole" in it, and a noticeable drop in coolant level over several months is normal. You need to keep an eye on the level and top it up once in a while.

 

Air in the system is very bad. Your cooling system is meant to operate with all parts and surfaces completely immersed in coolant, as that's how the anti-corrosion properties of the coolant work. Air equals corrosion. Also, with air in it, the system cannot be pressurized, which is one way boiling is controlled. Boiling (or vaporization of the coolant) is just as bad as a low level.

 

If the engine starts to overheat at idle, or in heavy traffic, and the gauge goes down when you rev it, the coolant is probably low. Best to check.

 

 

Radiator or block internally clogged with rust, scale, silt, gel, or externally blocked with road debris

 

The radiator is the engine's main heat exchanger. Unless coolant can pass freely through it at the speed the water pump and thermostat want to push it, it can't get rid of the heat it needs to get rid of, and deposits prevent fluid movement.

 

Any deposits at all in the radiator are bad and are caused by one of more of the following:

Incorrect coolant

Mixing incompatible coolants

Old, corrosive coolant

Use of tap water to mix with aftermarket coolants

When you pull the rad cap off and shine a flashlight inside, the coolant should be transparent (plus whatever color it was when put in), and the fins should be clearly visible.

 

If the fluid is murky, brown, smells like rubber, goopy, or if the fins have white, crusty deposits on them, you've got circulation problems, and likely corrosion problems inside the engine.

 

Old coolant gets acidic and corrosive, and will eat all sorts of internal parts, from your head gasket to the water pump impeller. It also cannot carry heat as effectively as fresh coolant.

 

Inexpensive silicated coolants (the cloudy stuff) can cause silt to build up in the engine's water jacket as well as the rad, providing an impediment to free flow of coolant. Honda emphatically recommends that you use their coolant and no other in their cars.

 

Coolant should be changed every two years with a non-silicate, non-borate type. Long-Life coolant is supposed to be good for five years, but I've never personally been comfortable with that. I change mine every two years or less.

 

Mixing coolants of different formulations can destroy the corrosion-inhibitors, leaidng to rapid corrosion, water pump, thermostat and radiator failure, as well as head gasket problems.

From Valvoline's Web site comes this PDF file on that subject.

If that PDF doesn't work, try here for a local copy.

 

More on coolant and coolant compatibility from Car and Driver magazine's Patrick Bedard:

http://www.caranddriver.com/article.asp?section_id=27&article_id=2334&page_number=1

http://www.caranddriver.com/article.asp?section_id=27&article_id=2264&page_number=1

 

It's always best to be safe and use Honda's own Type 2 premix.

 

A radiator problem peculiar to Northern regions is external corrosion of the fins. This is caused by winter and road salt, and reduces the fins to a white powder. The fins then crumble and fall off, and once they do, that section of the radiator cannot exchange heat with the outside air. Run your hand gently over the fins at the middle of the rad's core, at the very bottom, under the bumper. If they're crumbly, you'll know.

 

Warmer areas may suffer from sand, pine needles and other debris embedded in the lower half of the rad, which prevent air movement through the rad and thus impair heat exchanging.

 

 

Bad radiator cap

 

The radiator cap does several things. It

seals the system against the outside world (main seal function)

keeps the system pressurized when needed, so as to raise the boiling point of the coolant

allows excess pressure and coolant expansion to vent to the expansion reservoir (pressure seal function)

allows coolant to return to the radiator when the engine cools down (return seal function)

As you may have gathered from the above section, the radiator cap has three seals, any of which may fail independently of the others:

The main seal is the one that seals the cap against the top of the filler neck. Just a rubber gasket that operates just like one on the lid of a pickle jar. Simple and reliable.

A failed pressure seal will allow the coolant to boil at a lower temperature, and coolant will be able to travel freely and foamily to the expansion reservoir. This will cause localized hot-spots inside the engine, which can lead to premature head warpage, and may hasten head gasket failure. It will also cause the rad coolant level to be low, just like a failed head gasket.

A failed return seal will prevent the coolant from returning to the radiator as the rad cools off, causing a vacuum that can collapse the radiator's hoses. This will prevent the coolant from circulating if the hoses don't re-expand as the engine warms up.

A bad rad cap can cause similar symptoms to a failed head gasket, so it's a cheap first step to try before bringing it in. If you replace the rad cap and you still have bubbles in the coolant (or foam in the reservoir), then suspect the head gasket.

If the engine starts to overheat at idle, or in heavy traffic, and the gauge goes down when you rev it, the coolant is probably low.

 

Moreover, a neglected cooling system can load up the cap with crud and corrosion, preventing proper coolant flow in and out through it. Peel the seals back with your fingernail to check for goop. If you find any, a blast with a garden hose and probing with a toothpick should clear most of it out.

 

But anyway, a new rad cap is less than $20. Make a habit to change it every 5 years, just in case. It's pretty important.

 

 

Bad thermostat

 

This part is the traffic cop that controls when the coolant is allowed to circulate and when it isn't. It's the device that's meant to quickly allow the engine to warm up to its design temperature, but no hotter than that.

 

Thermostats can stick shut or open, get lazy, or fail to open at the correct temperature. Depending on how and when they fail, they will cause either overheating or underheating. Overheating usually happens when the thermostat fails to open, or fails to open enough. If it fails to close, the engine will run too cool, causing all sorts of other problems.

 

A cooling system full of rust, scale, silt, or gel will interfere with the thermostat's operation, causing even more cooling problems. Gunk can plug up the thermostat, causing overheating, or make it stick open, causing underheating. Incorrect installation of the thermostat (can be done, even by professionals!) will also interfere with thermostat operation.

 

Normally mounted in the top of the lower rad hose in modern Hondas, the thermostat senses engine heat in the coolant. It is supposed to open up when the coolant in the block has warmed up enough, allow the cooled coolant in the rad to flow into the block, pushing the hot coolant from the block into the rad.

 

When the thermostat is closed, a small bypass hose allows coolant to circulate through the engine block, around the business end of the thermostat, through the water pump, and back around again. This keeps block temperature even, and helps the thermostat warm up as well. Once the thermostat opens, the bypass is closed off by means of a special extension on the bottom of the thermostat.

 

Aftermarket thermostats are highly associated with overheating and underheating. Most Hondas require 78C (172F) thermostats (that's the opening temperature). Too many aftermarket thermostats are wrongly rated for your car and are poorly made. Your emissions system may not work correctly with a different rating installed. In addition, some aftermarket units lack a bleed hole, the absence of which can trap air and lead to overheating.

 

A new genuine Honda thermostat is about $30 and is guaranteed to work properly in your Honda. In my mind, it's foolish to trust such an important job to an aftermarket part. Changing it every 5 years is excellent preventative maintenance.

 

A good link with more info. "Jack" is not the best writer, but he's got lots to say:

http://www.users.bigpond.com/jack_stands/automotive_advice/cooling_system/engine_cooling.html#TSTAT

 

 

Electric fan not coming on

 

The engine's heat is removed from the coolant through the radiator. When you drive, the motion of your car is enough to push sufficient air through the radiator to effect proper cooling, but when you are stopped, or moving slowly in heavy traffic, your radiator needs help. This is what the fan does: It pulls air through the rad when the rad isn't moving.

 

The problem is that, in order to work, it needs to be turned on. There are various fuses, sensors, switches, relays, and several yards of wiring and connections concerned with turning the fan on, and they do go bad. The fan motor itself is very robust, and rarely goes bad.

 

The fan switch is immersed in coolant. When the coolant gets hot enough, the switch closes, and grounds either the fan itself, or a relay, which then provides power to the fan.

 

In some cars, if the coolant in the rad iCs too low, the fan switch may not be fully immersed in coolant and would thus sense a false temperature and not switch the fan on. Some cars have the fan switch deep at the bottom of the cooling jacket, others have it higher up. Higher up is more prone to this issue. Keep in mind that all but the very newest Hondas use two

 

Wiring and connectors on older cars begin to corrode and break down, which cause their own headaches.

 

Older Hondas (my '91 Integra for instance), have no relay for the fan switch. The switch simply grounds the fan, allowing current to flow, and the fan to come on. (The fan itself still has a relay though.)

Here is some troubleshooting information on this setup.

 

Newer Hondas use a relay to help insulate the switch from having to carry the full current that the fan's drawing. The idea is to help the switch last longer, but the downside is a bit more complexity and more parts to fail.

Thanks to poster Remco, here is an extensive troubleshooting guide for this type of installation. switches: One for the fan, one for the temperature gauge. This means that a gauge reading will not necessarily coincide with what's actually happening inside the engine. Bottom line: Check your coolant level in the rad AND the expansion tank, just in case.

 

(Note to users of Netscape, Mozilla and Firefox: Remco's page was designed for Internet Explorer. If you have trouble with the text being jumbled and difficult to read, reset your Fonts down one size as shown below, view the page, then set it back up again).

 

***************************

 

 

Failed head gasket

 

When the gasket goes, typically the first thing that happens is that combustion chamber gases are pumped into the water jacket. You will see this as bubbles in the expansion reservoir. This will quickly lead to low coolant level in the engine, and overheating at idle, even if the fan comes on, since the water pump can't move the coolant around properly any more.

 

If the engine starts to overheat at idle, or in heavy traffic, and the gauge goes down when you rev it, the coolant is low.

 

The symptoms are similar to a failed rad cap. If you top up the rad, replace the rad cap and the problem persists, the head gasket is definitely questionable. To confirm this, a garage can apply a pressure test (NOT a "compression test"), where air is blown into each cylinder in turn until the technician sees bubbles in the radiator. If no bubbles are seen, the problem is elsewhere, such as an external leak.

 

This can be accompanied by an expansion reservoir level that is much higher than normal, and which does not go down once the engine cools off.

 

If you choose to simply add fluid and ignore the issue, eventually oil and coolant will begin mixing together, and coolant will get sucked into the combustion chamber. Ignoring this is a good way to toast a perfectly good engine. Get it fixed early and there will be no further issues.

 

More on coolant and how corrosive coolant can cause problems, from Car and Driver magazine's Patrick Bedard:

http://www.caranddriver.com/article.asp?section_id=27&article_id=2334&page_number=1

http://www.caranddriver.com/article.asp?section_id=27&article_id=2264&page_number=1

 

 

Bad seal between radiator cap and expansion reservoir, or too much air in system after fluid change

 

When coolant expands, it needs to go someplace temporarily so it doesn't burst hoses or blow the rad. The expansion reservoir is where it goes.

 

The fluid pushes out of the pressure seal in the rad cap, and travels down the skinny rubber hose at the filler neck to the expansion reservoir.

 

As the engine cools off after you shut it down, the return seal in the cap opens up, and the coolant is sucked back in through that same rubber hose.

 

If the reservoir has run dry, the amount pushed out may not be sufficient to cover the bottom of the reservoir's intake pipe, leaving the system unable to pull the coolant back in, so you'll end up with air in the rad, and resulting loss of pressure. If the rubber hose is disconnected or split, the expanded coolant may end up on the road instead of the in the reservoir, leading to the same situation. And air in your rad is a bad thing.

 

If you've just changed the coolant, there will be some air trapped that will work its way loose back to the upper radiator tank. If there is a lot, there will be too much for the expanded coolant to push all the way into the reservoir. What this means is you'll have a situation similar to that immediately above, where the engine will be unable to suck in coolant from the reservoir. When you change the coolant, take the car for a drive after. Let it cool down, then check the rad for air. Top it off, do the same thing the morning after the next drive, and you should be OK from then on.

 

Regular checks of your coolant level, both in the expansuion tank and the rad, are important in any case.

 

 

Lower radiator hose collapsed

 

If you're using genuine Honda hoses, you'll never see this problem unless your rad cap has gone bad and won't allow coolant back into the engine.

 

When the water pump is turning, it's sucking water through the thermostat and the lower rad hose. That suction can cause the same sort of hose collapse as you get in a drinking straw when you try to suck a thick milkshake through it. If the hose is insufficiently reinforced on the inside, it can get sucked flat and coolant flow will stop. When you let off the pedal or shut the car off, the hose pops back to normal. If you use aftermarket hoses, not all of them will be of high quality, and may be prone to this phenomenon.

 

To check for this, rev the car hard with your hand on the throttle in the engine compartment, and watch the lower hose. If it doesn't collapse, it's probably fine.

 

This can also happen as the car cools off, if the rad cap return seal has gone bad.

 

 

Water pump impeller corroded

 

The only time you'll ever see this is if

you're using a low-quality aftermarket water pump, or

you've mixed incompatible coolants, or

the coolant has never, ever been changed.

If the impeller is gone or much reduced in size, coolant can't be pumped into and out of the rad, so it will boil and overheat.

Edited July 10, 2011 by Rpm90001