Trying to confirm blown HG

[Gardener]

Hi,

I wish I'd found this board 2 years ago! I know this topic has been beat to death here but I still have a few questions. Almost 3years ago my daughter bought a 98 Outback with 130k. Drove it all summer and to college (225 mi.) in the Fall. Coming home that Christmas in very cold weather it overheated within a half hour - pretty badly I think. I went up and found the radiator empty, filled it, no leaks, drove slowly, no problem, gradually sped up and got home without overheating. Ever since then it overheats if you take it on the highway in below freezing temps. Local driving is fine and warming it up at idle doesn't help but driving slowly for an hour or so does seem to help (but we don't have much data). Two shops (one a dealer) "couldn't find anything wrong". Finally she got it to a dealer while overheating and they said they were "very sure" it has a cracked block and needs a short block at $4400.00. From searching this board a blown head gasket seems more likely. What puzzles me is that it doesn't lose coolant, doesn't smoke, and theres no coolant in the oil or oil in the coolant. Then I found this message:

 

"Well, I hate to tell you this, but when the car overheated the first time it damaged/blew the head gasket some where. What is happening now is that you randomly get a break in the headgasket seal that causes the cooling system to become pressurized by the the engine's gases (intake charge/exhaust gasses) When that happens the coolant stops circulating. This causes the temp gauge to go up and the heater air to go cold. Heat goes cold because there is no more hot collant flowing across it to heat it up, and the temp gauge goes up because there is nothing flowing through the engine to carry the heat away to the radiator. Sorry, but I'm pretty sure you need a head gasket job.

 

Keith"

 

My daugher did say the heat doesn't work well when it gets hot so Keith's explanation fits. Is it possible that cold weather triggers the break in the head gasket? Any point at all in trying "block sealer"? BTW, my 99 Outback with more than 170k runs like a champ (don't know exact mileage because speedometer only works intermittently).

Thanks for any help!

[idosubaru]

they quoted you the price for the block to protect themselves. it's probably a head gasket.

 

imagine if you're a customer and go in with overheating car. shop quotes you $1,500 to replace the gaskets. then it's still overheating and the shop says "oh you have a bad block and that's $4,000". some people get seriously miffed at paying $1,500 and then needing a new block for that kind of change. so the easiest route...just quote a block replacement every time.

 

statistically speaking - making up numbers - you have a 2% chance of having a blown block and that number gets larger the more times you drive it while overheating. if you've been driving it as much as it sounds like then it's gradually degrading the block over time. all of that heat and repeated driving does bad things to gaskets and bearings and even cylinder sleeves. there's really no way to promise anything.

 

your symptoms are very common (for this motor, not head gaskets in general), nothing odd about what i'm seeing there.

 

but - you want to make sure that's it's not loosing coolant somewhere else and something very simple. have the radiator caps, hoses, leak points, thermostat and water pump ever been addressed? all of those are at or past replacement mileage and are over 10 years old now.

 

if you do need engine work, a cheaper alternative is to go for an EJ22 engine swap - it's easy to do on a 1998 EJ25 vehicle and the EJ22 is a more reliable engine.

 

and your speedo issues are common to 1999-ish vehicles for some reason.

[Gardener]

Thank you very much. What you say about the block vs HG makes sense and thanks for the tip about the EJ22 engine. My daughter *says* that since the first overheating she tries to stop as soon as the needle moves above normal and has never let the temp gauge get into the red. There is no coolant loss and the system has passed a pressure test. I've replaced the cap and thermostat but haven't touched the water pump. Somewhere I saw something about exhaust gases in the coolant - is there a way to test for this? You didn't comment on "block sealer". Would that be a "nothing to lose" situation or might it do further damage. Thanks again!

[WAWalker]

Yes, there are tests for HC's in the cooling system.

There is a chemical test, HC's react with the chemical and changes it's color. Tricky test to do on these engines.

A shop with a gas analyzer can "sniff" the cooling system to test for HC's.

 

"Block sealant" added to the coolant will do no good. Combustion is leaking into the cooling system, coolant is not leaking from the cooling system.

 

I don't know if there is anything to it, but in the winter time with the extreme temp. changes, I seem to see a lot more head gaskets failing on these cars than is the summer months.

[subsince77]

My experience, which is different from expertise, which others here can give, was that temperature didn't seem to make the overheating issue worse, but time on the highway did. Even in far sub-zero temperatures, mine would not overheat, even when I would drive it around the valley for multiple hours on errands, as long as I didn't go over about 55. As soon as I got out on the highway for somewhere between 15 minutes, and 40 minutes, it would suddenly overheat. I got away with driving daily for about two months while getting ready for an engine swap. But, I live near a small community, and can do all of that without ever getting over 50 mph. The only reason I'm chiming in, is that during the days, and weeks, that the car does not overheat, it runs just like normal. I found it EXTREMELY tempting to decide it was OK and head out of town with it. I am convinced that had I done so, I would have eventually fried my engine and the core would have been worthless. Don't do it, save what you can.

[idosubaru]

i would not use block sealer if you plan on keeping this vehicle for any length of time. whatever engine ends up in there - a new one or the original, i wouldn't want that block sealer all through the cooling system - heater core, radiator, hoses, etc.

 

you can do tests and if it fails that's a bad thing. but they don't confirm that the head gasket is not leaking. the EJ25 is a freak. it can pass compression, leak down, and hydro carbon tests. being known locally as having some subaru knowledge i've gotten questions from mechanics that couldn't figure out an overheating EJ25...passed all the conventional head gasket tests.

[nipper]

Give your daughter a pat on the back for knowing enough to watch the temp sensor and not letting the engine cook.

 

This is a very fixable engine. Yes you have a blown HG. Usually when people notice the car has over heated, the temp gauge has been pegged for who knows how long and ruin the bottom end.

 

Replace the HG with one from subaru, get a valve job, get the heds milled and continue on untill the doors fall off (about year 2020). Do not one just one HG.

 

Do not use any sealers, as they only operate at 14-16 psi, not the 10-15,000 psi in the combustion chamber.

 

nipper

[subaru360]

This seems like a typical head gasket. But if you have been driving for years like this, I would be very careful about putting money into this engine. The more you drive it the more likely it has warped or cracked heads and/or block.

[Gardener]

Thanks everyone! Obviously I wish we'd addressed this sooner, but it has behaved just like Subsince77 describes below except it has to be highway driving AND subfreezing so it only happens once or twice a year (when she's at school it's all local driving). I think we'll probably try the head gasket/ valve job approach and hope that the block is ok. I'll let you know. If not - her previous car is a 91 Legacy that we retired due to worn out axels, body damage and more but we still have it. I'll have to figure out what motor is in it.... Thanks again!

 

My experience, which is different from expertise, which others here can give, was that temperature didn't seem to make the overheating issue worse, but time on the highway did. Even in far sub-zero temperatures, mine would not overheat, even when I would drive it around the valley for multiple hours on errands, as long as I didn't go over about 55. As soon as I got out on the highway for somewhere between 15 minutes, and 40 minutes, it would suddenly overheat. I got away with driving daily for about two months while getting ready for an engine swap. But, I live near a small community, and can do all of that without ever getting over 50 mph. The only reason I'm chiming in, is that during the days, and weeks, that the car does not overheat, it runs just like normal. I found it EXTREMELY tempting to decide it was OK and head out of town with it. I am convinced that had I done so, I would have eventually fried my engine and the core would have been worthless. Don't do it, save what you can.

[idosubaru]

it has to be highway driving AND subfreezing so it only happens once or twice a year (when she's at school it's all local driving).

once or twice a year sounds very odd, make sure you're not loosing coolant. bubbles in the overflow tank when it does overheat - that's a sure sign of head gaskets on this motor. tell your daughter to listen for that next time it does it. once/twice a year is not indicative of headgasket unless it is really only driven more than a few minutes that number of times a year.

[Gardener]

It is odd, which is partly why it's taken us so long to address it. She really doesn't do much highway driving at all and in warm weather she's never had a problem on the 3.5 hour drive to or from college. It doesn't lose coolant so I was convinced that it had to be a circulation issue of some kind, but I didn't know that a blown gasket could pressureize the system and stop circulation. All I can guess is that some kind of differential expansion/contraction in cold weather breaks a marginal seal. In any case we sent her back to school in our 99 Outback - I was tired of rescuing her - so I have the car now and I can check for bubbles. Thanks for the tip!

 

once or twice a year sounds very odd, make sure you're not loosing coolant. bubbles in the overflow tank when it does overheat - that's a sure sign of head gaskets on this motor. tell your daughter to listen for that next time it does it. once/twice a year is not indicative of headgasket unless it is really only driven more than a few minutes that number of times a year.

[idosubaru]

probably a head gasket with good timing on the road trips home. but time will tell.

 

the bubbling in the overflow tank is a sure sign - that's the gases in the coolant getting pushed out the expansion tank. you can often hear them bubbling once the car is shut off.

[mnwolftrack]

A blown headgasket will force air into the cooling system, and air bubbles get trapped here and there and are also responsible for the loss in heat through the heater because an empty heater core does not stay hot.

 

The coolant has to go somewhere, and it mainly gets pushed into the overflow tank on this engine. On other makes/models, it can get blown out the exhaust in the white billowie clouds (but this is not what happens on the subi's). Another key sign of a headgasket let is 2 fold in the overflow bottle. 1) make a mark with a magic marker when the engine is cold and mark the location of coolant over time. Always check it when it's cold (checking it hot when you marked it cold would be expected to show a change) if you marked it cold. In addition, combustion gases getting blown into the cooling system inevitably will bring along some oil with it. If the headgaskets are blown, you will likely see black nasties floating in the overflow and clinging to the walls. The combination of oil in the overflow bottle, overheating after getting into town after a drive on the interstate, loss of heat, and the temp gauge going up and down real fast were enough for me. The gauge going up and down real fast is from it getting hit by bubbles, then coolant, then bubbles, etc....

 

I would doubt you have a cracked block considering the car sounds quite drivable. You will likely be able to get away with new gaskets (dealer updated multi-layer steel only), resurfaced heads, and a possible valve job (may not be needed). Worst case scenario, the block might have to be resurfaced if it is found to be warped or pitted.

[Gardener]

Thanks mnwolftrack, I'm learning a lot! When this all started I assumed a circulation problem since no major coolant loss, but I didn't know blown HG could do that - I would have expected the white smoke. The overflow tank IS black on the inside (and when I drained the coolant it seemed slightly thicker than normal) so the evidence is mounting. I don't really trust the local dealer and there is a good mechanic in town (though not a Sub specialist) so I'll insist on the official gaskets. BTW I lived in Deephaven, MN as a kid. Fond memories of canoe trips Up North.

 

A blown headgasket will force air into the cooling system, and air bubbles get trapped here and there and are also responsible for the loss in heat through the heater because an empty heater core does not stay hot.

 

The coolant has to go somewhere, and it mainly gets pushed into the overflow tank on this engine. On other makes/models, it can get blown out the exhaust in the white billowie clouds (but this is not what happens on the subi's). Another key sign of a headgasket let is 2 fold in the overflow bottle. 1) make a mark with a magic marker when the engine is cold and mark the location of coolant over time. Always check it when it's cold (checking it hot when you marked it cold would be expected to show a change) if you marked it cold. In addition, combustion gases getting blown into the cooling system inevitably will bring along some oil with it. If the headgaskets are blown, you will likely see black nasties floating in the overflow and clinging to the walls. The combination of oil in the overflow bottle, overheating after getting into town after a drive on the interstate, loss of heat, and the temp gauge going up and down real fast were enough for me. The gauge going up and down real fast is from it getting hit by bubbles, then coolant, then bubbles, etc....

 

I would doubt you have a cracked block considering the car sounds quite drivable. You will likely be able to get away with new gaskets (dealer updated multi-layer steel only), resurfaced heads, and a possible valve job (may not be needed). Worst case scenario, the block might have to be resurfaced if it is found to be warped or pitted.

[idosubaru]

the tank being black isn't necessarily very meaningful since they get dirty and even vehicles with perfectly fine head gaskets have dirty, nasty overflow tanks. but like you said when multiple things start pointing one way....

 

if you get an independent to do this job we can help you put together a list of things that might be specific to subaru's that he may not know. like what parts to only use Subaru parts on and what other items may need addressed. when you're ready, ask for some info on that and we'll help you get a top notch job out of it.

[nipper]

No one cleans the tanks, its because they are a real pain to do. I cleaned mine and it took some chemical experimenting to do it. Arm and hammer and warm water and a large test tube cleaner worked best.

 

nipper

[aircraft engineer]

I used a pressure washer and blasted it out.

 

Most of it came right out.

 

Some borax or dishwasher dry soap might have helped, though, to cut thru the "gunk" that had collected over the years.

 

Then if you have a contrasting color paint pen (I used a purple pen - yeah, it was on sale at an art store), go around and mark the hot/cold lines on the tank so they are more easily read.

[davebugs]

To clean the reservoir. Rocks/gravel and I have a favorite cleaner called Blaster that I buy by the gallon at the parts store. I don't think it's a national brand.

 

Typically Cascade gel works well. Learned it from a rediator guy. Works better than a lot of commercial radiator flush products. Some cars you add it to the water and drive for a day or so before a flush and fill.

 

My bottle of Cascade gel is used only for cars (actually it works pretty well in ceramic shower stalls too). So make sure you shake it up first.

 

The gravel works just like when you use it to remove rust in a gas tank.

 

My overflow tank had a factory pin hole. When you're shaking put your finger over it or you'll get wet.

 

Dave

[nipper]

To clean the reservoir. Rocks/gravel and I have a favorite cleaner called Blaster that I buy by the gallon at the parts store. I don't think it's a national brand.

 

Typically Cascade gel works well. Learned it from a rediator guy. Works better than a lot of commercial radiator flush products. Some cars you add it to the water and drive for a day or so before a flush and fill.

 

My bottle of Cascade gel is used only for cars (actually it works pretty well in ceramic shower stalls too). So make sure you shake it up first.

 

The gravel works just like when you use it to remove rust in a gas tank.

 

My overflow tank had a factory pin hole. When you're shaking put your finger over it or you'll get wet.

 

Dave

 

I never tought of the gravel before

 

that would work.

 

nipper

[telemarkskier]

hey guys, great info on this thread. My 97 legacy gt has been overheating after long highway drives over greater than 100 miles, only when i slow for a toll or get off the highway. I am thinking its hg, after doing much of the trouble shooting listed in thread. any recomendations for parts (genuine subaru hg, what else) and a good mechinic in the boston area?

 

Thanks.

[nipper]

hey guys, great info on this thread. My 97 legacy gt has been overheating after long highway drives over greater than 100 miles, only when i slow for a toll or get off the highway. I am thinking its hg, after doing much of the trouble shooting listed in thread. any recomendations for parts (genuine subaru hg, what else) and a good mechinic in the boston area?

 

Thanks.

 

head gasket must be from subaru, everything else can be a good name brand. Its important that a good machine shop mills the head, thats 97% of the reason why they fail again.

 

nipper

[idosubaru]

My 97 legacy gt has been overheating after long highway drives over greater than 100 miles, only when i slow for a toll or get off the highway..

those are not typical EJ25 head gasket symptoms. you need to check for coolant loss, thermostat sticking and the water pump. you might have a very simple problem.

 

call the local subaru dealer and see if they use a particular machine shop in town, that might be a good place to start. i like finding someone with subaru experience.

[telemarkskier]

thanks for the input. I have noticed bubbles in the overflow tank of for coolant. I am thinking HG, as i have ruled out most other issues. Would the bubbles be a clear way to diagnos?

 

Thanks.