coolant overflow reservoir is bubbling?

99 2.5gt limited 116k miles. Just bought the car, havnt seen any overheating on the temp gauge or oil residue in the overflow. Ive hear this could be signs of a bad headgasket? Previous owner said Head gasket/timing stuff was all done at 90k and hes in the process of mailing me the proof it was done.

Pretty much yeah. It's likely a bad head gasket allowing combustion gasses to work their way into the coolant.

That sucks.. How much on average is a new headgasket on in of these if i got it done at a local shop?

A lot more than you'll want to spend. Don't let a shop do it if they are not familiar with Subaru's at all. There's a reason they have to be done again, as they weren't done right the first time.

Originally Posted by Kennyfvholla

A lot more than you'll want to spend. Don't let a shop do it if they are not familiar with Subaru's at all. There's a reason they have to be done again, as they weren't done right the first time.

Well the reason i went right to asking about the price was because im not confident i can do it myself

I've never seen or heard of anyone paying to have it done and get out for less than $1,200

Originally Posted by Kennyfvholla

I've never seen or heard of anyone paying to have it done and get out for less than $1,200

Yeah i just looked it up and it seems like anywhere from 1200-1800 ish. Anyways there doesnt appear to be any overheating at the moment but i havnt taken it for more than 5 mile drives at a time. If its not overheating should i just not worry about it for the time being?

Hello;
Before I would freakout, make sure that the radiator cap is up to snuff. A weak one would cause the bubbling. A quality Stat or Oem would be my first choice. What brand of thermostat do you have? An OEM with the bypass ball would be my first choice. Drive it and keep your beady eyeballs on the situation. Contamination of the overflow bottle is a sure sign, Steven.

Originally Posted by Datsik

Yeah i just looked it up and it seems like anywhere from 1200-1800 ish. Anyways there doesnt appear to be any overheating at the moment but i havnt taken it for more than 5 mile drives at a time. If its not overheating should i just not worry about it for the time being?

Originally Posted by snederhiser

Hello;
Before I would freakout, make sure that the radiator cap is up to snuff. A weak one would cause the bubbling. A quality Stat or Oem would be my first choice. What brand of thermostat do you have? An OEM with the bypass ball would be my first choice. Drive it and keep your beady eyeballs on the situation. Contamination of the overflow bottle is a sure sign, Steven.

Like Steven has said, I wouldn't worry about it just yet. Making sure everything else is up to par and keep an eye on it. Even if the car isn't overheating yet, another good sign is that the gaskets are leaking is that general warm time for the engine (how long it takes to get to full operating temp from a cold start) will shorten.


Also, another reason that there could be air bubble in the reservoir is if there is an air pocket in the cooling system. Make sure the entire system is purged of air. Next morning you go out, open the cap and make sure that the radiator is completely full. Make sure the overflow is topped off to where it needs to be as well.

Thanks so much guys i actually think i might know why this is happening. First off the car takes a good while to warm up so thats good. And second i have noticed after driving it there is drips of coolant near the radiator cap so maybe the seal on it is gone or something. Ill check it out tomorrow. And i dont know what brand thermostat i have id have to check. And when i checked the overflow the coolant was very clean in there but on the walls there was a tiny bit of brown here and there, so im not sure how bad its supposed to be to really know but it looks ok to me

also not sure if this helps, it is nighttime but i was able to run out real quick and start the car (cold start) while watching the overflow, and i let it run for about 2 minutes, and there was not even one bubble during that time. So is that any help? My thoughts were that if it is exhaust gas getting into the coolant system, wouldnt that happen anytime the engine is running whether its hot or cold?

Ours cost over $2,500 when my family had it done. Obviously got ripped off considering 75k miles later, I also get a small amount of bubbling in the overflow reservoir...
...and yet I'm going auto-crossing in two weeks! Probably not the best idea but I figure 4 minutes worth of full throttle can't be TERRIBLE for it.

Originally Posted by Datsik

also not sure if this helps, it is nighttime but i was able to run out real quick and start the car (cold start) while watching the overflow, and i let it run for about 2 minutes, and there was not even one bubble during that time. So is that any help? My thoughts were that if it is exhaust gas getting into the coolant system, wouldnt that happen anytime the engine is running whether its hot or cold?

Not necessarily, because the coolant circulates differently until the engine is warmed up. Though, honestly, I'm not familiar with the exact workings, so I suppose I'm not the best one to answer this question.

first step is to make sure the cooling system is bled properly. take the bleeder screw out of the top of the rad on the passenger side, make sure the rad is full and let the car come up to temp with that removed. once the car is hot and there arent any bubbles coming out of that hole, put the plug back in. the car will not overheat in just 5 miles if they aren't THAT bad yet, usually it takes 10-30 miles, sometimes more. also smell the overflow, if it reeks like raw exhaust, that is a giveaway.

fire it up, let it get warm, drive it pretty hard for 10 miles. then pop the hood and check the overflow bottle. if it is more than a little too full, you need head gaskets. they overheat when a lot of the coolant gets pushed out of the rad and into the overflow

Originally Posted by Datsik

And second i have noticed after driving it there is drips of coolant near the radiator cap so maybe the seal on it is gone or something. Ill check it out tomorrow. And i dont know what brand thermostat i have id have to check.

Your radiator cap may not be functioning correctly. Get a new one, along with a bottle of coolant. And then make sure that you purge any air from the system.

Originally Posted by Kennyfvholla

Also, another reason that there could be air bubble in the reservoir is if there is an air pocket in the cooling system. Make sure the entire system is purged of air. Next morning you go out, open the cap and make sure that the radiator is completely full. Make sure the overflow is topped off to where it needs to be as well.

After you do this, install the new radiator cap.

Originally Posted by Datsik

also not sure if this helps, it is nighttime but i was able to run out real quick and start the car (cold start) while watching the overflow, and i let it run for about 2 minutes, and there was not even one bubble during that time. So is that any help? My thoughts were that if it is exhaust gas getting into the coolant system, wouldnt that happen anytime the engine is running whether its hot or cold?

You will not see any bubbles until after that car has pretty much completely warmed up. Coolant is ONLY circulated within the motor until the coolant has come to temperature and starts to open the thermostat. The thermostat opens and closes as necessary to keep the coolant inside the engine at optimal temperature. Once it gets hot enough, it opens to pull the cooler coolant mixture from the radiator. As that enters the engine, some of the hotter coolant mixture leaves the engine and gets cooled by the radiator. It is constantly circulating.

Originally Posted by Datsik

And when i checked the overflow the coolant was very clean in there but on the walls there was a tiny bit of brown here and there, so im not sure how bad its supposed to be to really know but it looks ok to me

You won't see anything mixed in with the coolant. The crud will start to buildup on the walls towards the top of the reservoir, and some will float around.

Originally Posted by adb140275

first step is to make sure the cooling system is bled properly. take the bleeder screw out of the top of the rad on the passenger side, make sure the rad is full and let the car come up to temp with that removed. once the car is hot and there arent any bubbles coming out of that hole, put the plug back in. the car will not overheat in just 5 miles if they aren't THAT bad yet, usually it takes 10-30 miles, sometimes more. also smell the overflow, if it reeks like raw exhaust, that is a giveaway.

fire it up, let it get warm, drive it pretty hard for 10 miles. then pop the hood and check the overflow bottle. if it is more than a little too full, you need head gaskets. they overheat when a lot of the coolant gets pushed out of the rad and into the overflow

I did exactly as you said. First i replaced the cap with a new one. Then i check the coolant level its right at full mark on bottle. Then i completely removed the purge plug, started the engine, and let it run for about 20 minutes untill it came up to temp. I didnt really notice any bubbles per-say buy i did noticed a little whirling and waving in there, it could have been bubbles. Well after waiting that 20 minutes i was satisfied. So i plugged the purge hole and not 30 seconds later the fan kicked on. ( should i have waited till the fan kicked on before i plugged the whole? Almost like an indicator the car is now above temp so fan comes on..) so then i just got in and drove off. On my way to the store the Check engine light came on and that was that. I probably only drove 5-8 miles and i did not beat on it or drive it hard like you said because it needs some TLC (oil change trans flush, diff fluid change) and i want to do those things before i drive it hard or try to overheat it for diagnostic reasons.

So now im more concerned with the CEL.

Also the previous owner said sometimes the speedometer stops working and i never noticed it until this drive ( only driven it 3 times since i registered it a week ago). Could tha have something to do with the CEL?

EDIT: WOW, i just researched the speedo and its a common problem with the 99's. Apparently the miles stop going up when the speedo is out? So i could have bought a car with 180k miles but it says 116k on the odomoter.. not a great feeling right now and actually really stressed out about this car now.

I'm almost sure there's a lemon law in Mass. I would bring it to shop and see what they say. Maybe you could get your money back unless you bought as is.