Noob to subies and another overheating issue.

[weshole]

First off, I did search quite a bit and did not find a definitive answer so here goes. I'll try to be as thorough as possible.

So, I bought this car a few weeks ago. Details on the car... 1996 Legacy Outback, 2.5L, 180*** miles. Details from previous owner is that it came in to his workplace (salvage yard) with blown head gaskets. So, he bought it, replaced both hg's, the water pump, and timing belt. All of which was done in April and his wife has been driving it without issue up until the day I bought it.

First known issue, last Saturday, the wife and I were taking this car on a 50 mile trip for the eve. Within the first 10 miles, I noticed the heat was diminishing and I look down to see the temp gauge was just about pegged. Of course I pull over and shut the car down. I popped the hood to investigate. Noticed that the coolant had overflowed only slighlty. I let the car cool down for a while and then limped it back home. I checked everything I could think of such as coolant level, fans operation and all seemed to be OK.

So I decided to check the t-stat. I drop the lower hose/housing and notice not a lot of coolant came out of the radiator end and what did come out was nearly all water. So, I then proceeded to test the t-stat under boiling water. I opened when the water came to boil so, I reinstalled it. At this time I came to the conclusion that as a result of the colder weather (30's) that the water in the radiator froze and but putting a propper mix of water/coolant would take care of issue. I then proceed to bleed the system out. This took quite a bit longer than it should have as I was not able to get coolant to properly flow. I could fill the radiator but it wasnt getting to the block. I did not know about the bleeder screw on the radiator so I resorted to removing the upper hose from the t-stat and filling the engine itself with coolant that way. It seemed to work great. I got heat back and the car seemed to cool like it should. The wife used the car the whole week after to commute back and forth to work with the car without an issue but it never did go very far for very long so it may not have given her any issue because of this.

So yesterday eve. (Friday) I decided that I want to take the car and drive it to my parents place (about 12 miles out of town). I head out of town driving 55 mph and no issue until I slowed down to make a turn. It then started to do the exact thing it did the previous weekend. the coolant gauge normally sits at just below 1/2 way but when it overheats, the gauge climbs rapidly and I lose heat. I pull over and it boils over a little bit. I then proceed to check for any leaks which there is nothing visible. I start to grab hoses. Upper hose is hot and has pressure. One heater hose is hot and has pressure (closest to the passenger side) The other is cold and has pressure (what I would say is the driver side). I reach underneath the car and grab the lower hose and it's ice cold. I let it cool off meanwhile I call for a ride home to get some small tools and coolant.

I get back to the car and pour about a quart of coolant into the radiator and car acts normal again. So, I start the trek home. I get to town and am about 5 blocks away from home and it starts to do the same thing again. Only this time, it gets to full hot and the t-stat opens and it drops down to normal. But, it does seem to act erratically off and on since that. I run it for a 1/2 hour and it gives no issue. Frustrated, I give up for the evening.

The next morning (today) I run to the parts store and get a t-stat and install it. Bleed the system just as I had so many times before and it seemed to be o.k. So, I then test drive it out to my parents again. Well, I made it almost all the way to his place before it happens again. I approach an intersection, stop, and proceed to continue and it starts acting up. It starts to climb to about 3/4 way up the gauge rapidly and then it drops drastically back to normal. It does this a few more times in the last few miles to the parents place and goes to full peg as I'm driving down his driveway. I shut the car off and pop the hood. This time it has boiled over a little bit more than the first time. I then grab all the hoses again. Same result. Upper hose hot and pressure, lower hose cold, one heater hose warm and one cold.

I start to think that I'm not getting all the air pockets out of the cooling system. that's the only thing (other than head gaskets) that would possibly cause such a drastic climb in temp. So, I spend a long time trying to bleed the whole system out and let the car sit and idle afterward for 45 minutes. Again, I figure that I got all the air pockets out of the car and proceed home. Alls well until I almost get home. and then it happens again.

So now I'm pissed off and figure my head gaskets are blown. So, I bring it to work (repair facility) and use our snap on combustion leak tester to see if in fact I do have a blown head gasket and its pushing exh gas into the coolant system and thus creating air pockets causing my issue. Anyone familiar with this tool knows that you put a special fluid (blue in color) into both chambers of the tester and stick it on the radiator where the cap goes. If it detects or comes into contact with any exh gases, the color turns from blue to green and even yellow if its bad enough. Well. it passed the test and the fluid stays blue. I tested it both ways that snap on says to test it. So that tells me that my hg's are good. So I have one of the techs test my rad cap for proper pressure retention and it fails miserably. So, I buy a new cap and install it and bleed the system out (by now I have found the bleeder screw on the radiator by the upper hose) It bleeds out without a hitch. So, I then take it out of town and try to make it re-occur. I drove quite a bit further this time and it works great. So, I take it home and park it for a few hours.

I decide a few hours later to take it for another test drive to verify it is indeed fixed and while I was out of town on the highway, it worked great. But, it started to act up again as soon as I came back to town. It went a little past 1/2 way a few times but the t-stat seemed to open and it dropped back to normal a few times and then it went to full hot again rapidly and I again lost heat. I pull into the driveway within a minute of it pegging again, I pop the hood and check it over. It is no longer boiling over (good cap) but the hoses are the same as before.

So, wtf am I missing? do I have a faulty t-stat? The one thing that makes me question this is all of the OEM ones have a little bleeder poppet on it and they seem to be offset too. My tech program at work (Alldata) says the same thing and to position the little bleeder facing outward. But the aftermarket one (stant brand) is just like a standard t-stat without such poppet.

The parts stores are closed in my small town tomorrow so I cannot get a different one yet. What I want to try is to either take the t-stat out completely or take the old one and gut it out and use it as a restrictor of sorts like we used to do on our race cars. Has anyone tried this before? Is it safe to run this engine without a t-stat?


PLEASE HELP?!?!?!

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[Tony05]

I have some what of the same problem in my 2000 outback 2.5L. It does overheat a lot but thats because I do push it a lot and since I live in Florida it gets to about 90+ degrees + humidity. I to got a new water-pump installed and thought that might fix the problem but nope.

What I suggest doing is going out and driving the car somewhere with no cars around and keep driving the car untill the temp meter goes all the way up, the engine should overheat and smoke will start coming out, if that happens than its not the guage, if it doesnt its the guage.

Though that is a very dangerous thing to do. If you live in a small town id take a wild guess and say you dont have any Subaru dealerships around, which would be your best choice for the problem. Usually independent shop stores like advanced autoparts and autozone dont know crap when it comes to cars, they are all stupid their, and dont know much about car problems.

If you have a Subaru dealership around, id suggest going their and maybe they would be able to tell you the problem, thats what id do at least.

[weshole]

Well I know it is not the gauge as like I stated in my o-so-long description, I lose heat too. Which to me sounds like an air pocket in the cooling system. Whether from not fully purging/bleeding the system or a head gasket allowing exhaust gases to force its way through into the cooling system. And your right about living in a smaller town and not having a local Subaru dealership. Closest is 50 miles away.

[Tony05]

ya thats pretty far but thats what id recommend doing since it hasnt started snowing to hard yet, maybe u can find the nearest subie dealership and call them up and see if they would be able to assist u before thinking of going their

[rockhopjohn]

Originally Posted by weshole

Well I know it is not the gauge as like I stated in my o-so-long description, I lose heat too. Which to me sounds like an air pocket in the cooling system. Whether from not fully purging/bleeding the system or a head gasket allowing exhaust gases to force its way through into the cooling system. And your right about living in a smaller town and not having a local Subaru dealership. Closest is 50 miles away.

Those are the CLASSIC failed head gasket symptoms. Also, those Stant thermostats are crap, always stick with the OEM thermostat. My guess is the guy bought it from didn't have the heads resurfaced, which has led to an accelerated failure of the head gasket; or he never did the work in the first place and just lied to you. In the mean time, I would recommend drilling a small hole in the plate on the thermostat. This will allow any trapped gasses to get through the thermostat and prevent any vapor lock at that point. Doing this allowed me to drive with a blown HG for almost a year before finally ditching the car.

There is extensive discussion of these head gasket issues here:

http://www.subaruoutback.org/forums/...?s=&forumid=88

[weshole]

I took the old t-stat and took the guts out of it and reinstalled it. Well, it no longer overheats which is a good thing. That's the only good thing. Negative #1, obviously because the coolant is continuously flowing, it doesnt get very warm which is apparent on both the gauge and the actual heat output. Negative #2, after a lil bit of driving, I pull into driveway and open the overflow and see bubbles coming from the tube. either the air pockets are not fully worked out or it is head gaskets. I am ordering an oe t-stat from subaru Tomorrow. What I may try is to drive the car like I did today and get the bubbles going again and if they do, use the combustion leak tester again only this time on the coolant reservoir where the bubbles are going.

Im affraid it is going to be head gaskets.

[rockhopjohn]

Originally Posted by weshole

I took the old t-stat and took the guts out of it and reinstalled it. Well, it no longer overheats which is a good thing. That's the only good thing. Negative #1, obviously because the coolant is continuously flowing, it doesnt get very warm which is apparent on both the gauge and the actual heat output. Negative #2, after a lil bit of driving, I pull into driveway and open the overflow and see bubbles coming from the tube. either the air pockets are not fully worked out or it is head gaskets. I am ordering an oe t-stat from subaru Tomorrow. What I may try is to drive the car like I did today and get the bubbles going again and if they do, use the combustion leak tester again only this time on the coolant reservoir where the bubbles are going.

Im affraid it is going to be head gaskets.

Yeah, it certainly sounds like it. Next time it is bubbling stick your nose in the coolant tank, you will know immediately if that is fresh exhaust bubbling out, versus air that just got entrained in the system.

[weshole]

O.K. It's confirmed. Head gaskets it is. Turns out the guy who didnt replace it failed to replace the head bolts when he did the job. My question now is, when the job is all done, what should I need to know or do when bleeding the air pockets out of the engine when its up and running again. I've read that its hard to get the air pockets out of the engine and there may be a certain sequence to do this.

[Charlie-III]

1-There should have been no issue reusing the head bolts on a NA.
2-If you do the next set, use the turbo torque specs, not the NA ones.
3-There are a ton of "how to's" on bleeding a Subaru cooling system. The NA's are easier than the turbo cars.

[weshole]

What are the turbo specs and why do you use them instead?

[weshole]

Well, that's a mute point anyway as I had it finished before I read the post. Thanks though.Turned out he did replace the head gaskets. However, unlike the mls gaskets Subaru wants you to use, he used a standard graphite faced gasket from Victor. you could see exactly where it was leaking. I used the mls gaskets made by Fel-pro. I did compare them side by side to the Subaru ones and they are identical. I wish I had taken pics to show this. The only reason I used the Fel-pro ones over the Subaru ones was the fact that the Fel-pro gaskets came as a complete kit and once I opened it, I owned it as to with the Subaru individual ones I could return. I did end up using new head bolts just to be safe. They had been used and re-torqued at least twice so that was my reasoning behind that. It bled out just fine. One thing I did find was that the aftermarket (Stant) brand thermostats use a standard t-stat housing without a bleeder nipple and is not offset at all. It may not be that big of a deal but, I did order the right one for the application. I did add half a bottle of Royal Purple Purple Ice coolant additive for added insurance. That was more for peace of mind than anything. Car runs great and the wife is happy. So, I'm content with that. Now, on to the other quirks with the car. Thanks to all who replied with the info.