I recently purchased a 4EAT 2003 Subaru Forester XS. Head gaskets were clearly bad and the car was overheating. I pulled the motor and did the head gaskets(Fel-Pro), cleaning up the mating surfaces diligently. We checked the heads with an machinists level and the drivers side was perfect and the passenger side was not far off (don't remember exact number). In the process I found that the previous owner had put "Stop-Leak" or something of that nature in the cooling system. I did my best again to clean the block and the heads of said material. To be on the safe side I ordered a new Radiator (along with OEM T-Stat). I also did a timing belt and full component kit. Since then I've had overheating issues. Car idles around 95C and if I take it for 2-3 miles it gets over 105C (way too hot). I have flushed the cooling system with the prestone additive and a garden hose (Has good flow). The next thing I plan to do is have a professional coolant flush. My suspicion is that either the head was in worse shape then I thought, or possibly one of them is cracked. Upon inspection of the head gaskets they look perfect from both the top and bottom with no fluid leaking. I basically am wondering if anyone else has experienced a similar situation and solved the problem? If I don't get this figured out by this weekend I'll be pulling the motor (EJ251) back out and heading to the machine shop. Thanks for reading! -Eazy
Thanks for the reply @phi11 . I have attempted to burp the air by letting it idle squeezing the top rad hose. Did this for about 15 mins. I even drained and refilled the radiator by the service manual, being careful not to put the coolant in too fast. It is possible it has air in it, but I don't know how to get it out. Eazy
I have also tested with a thermalcouple in the coolant stream and it basically matched the OBD2 reading.
@Sjogun showed me a nice way to do it but I can't recall exactly what he did, maybe he can post it here
The fact that the coolant at the radiator hose itself was around 100C makes me think its not air, but I am not 100%.
Are you using an OEM thermostat? I'm serious here, there have been many instances of forester owners on SF.org that have used aftermarket thermometers and the problem was immediately solved with an OEM thermostat.
I have a funnel that fits into the radiator fill stalk, fill the funnel half way with coolant, and let idle(hvac off) until the fans come on. Might take 15-20 mins, look at the temp gauge every once in a while, if it starts going above half, shut down(air should burp out) then restart..also I'd pick up an oem radiator cap pronto
For the turbo cars, I thought you mentioned something about pulling off one of the lines from the fill tank and then raising the free end of that line above the level of the funnel, or something?
I don't think you'll need to do that. A coolant funnel should be all that's needed. The decent universal ones are around 30 bucks or so and will save you a whole lot of heartache and headaches when it comes to getting your coolant system squared away.
I am surprised @ShortytheFirefighter didnt mention this fix but it involves a road flare and 5 gallons of gas. -Did the machine shop test the heads after they machined them? -Did you check if the block was within spec? -Like @Sjogun said, get an OEM radiator cap -If you did burp the system correctly, you may try replacing the thermostat again and see if that resolves it.
-Heads were not machined, just cleaned up by me (see my first post). -I checked both the heads and block for being warped, both seemed good. (Drivers side perfect, passenger side almost perfect... dont know exact number) -Will do on the radiator cap. -I have 2 brand new thermostats (one OEM, one non) and I have tested both of them after burping the system. (I have drained and filled the cooling system around 5 times over the past week) I have also tested both thermostats in a pot of water and they both open between 77C and 78C. Thanks for the response. I'm having a professional flush tomorrow so hopefully that will eliminate(or reduce) the question of air in the system.
Is it right that you're supposed to have the HVAC temp control set to full hot while doing the burping, or are the Subaru heater cores full flow/valveless?
Over lunch today I put my radiator cap from my Impreza on (OEM orange sticker with Japanese written on it). From cold I drove the car for about 10 mins. Temps still got very hot (around 110C) before I parked the car. I let it sit in park and put the heat on (heat had not been on at all since cold) and it was blowing cold air. Let it run for about 3 mins and it still was blowing cold(AKA not hot). When I got out it looked like coolant was coming out of the overflow on the drivers side. Not really sure what the heat being cold means, possibly that hot coolant is not getting to the heater core.
Use that funnel trick, it sounds like you have a bubble in there still. Bottom hose is probably cold too. If you pull if your cap while running...cold! ..do you see bubbles coming out that could be exhaust gases, is the overflow tank dirty(soot, or oil coating the inside of the overflow reservoir)? Also this. Good luck!
Yeah that just a way to minimize air being trapped in there while filling it, also it fills faster, time is money . This not being a turbo car, and no to bleeder screw(like the old ones) just the funnel and time is all you need..you can try revving the engine to push some air out, jacking the front of the vehicle up can help as well.
Having the heater on will only make it take longer to reach full temp, there is no heater valve in Subarus, unless Midas or someone added one.
Why didn't you deck the heads (at a minimum, or fully rebuild them) when they were off? I'm not that familiar with over heating issues, but since the head's weren't perfect when they were reinstalled, perhaps that is the issue. It seems like common sense to redo the head's when they are off...
As the page from the factory manual that Sjogun posted shows, did you make sure to install the thermostat with it rotated so the jiggle pin is at the front of the car? I think It needs to be in order to allow the trapped air to be released. BTW that is a terrible technical illustration, the (A) callout line points at nothing ; )
Almost 100% sure it's your heads. I had the same issues with my 07 LGT tried alllll of the things above. Ended up pulling the motor and decking the heads, been perfect for the 2 months
Had a professional flush today, didn't help at all. I agree with everyone who said it could be the heads and I am taking them back off and sending them to the machine shop. I'll update once the deed is done. -Eazy
Does the bottom hose get hot? y/n? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Where was this "professional flush" done?
I'm putting my chips on its the heater core...stop leak is aweful nasty stuff and and will clog the ever living $h*t out of the heater core, which always has coolant flowing through it. I'd say flush just the heater core before trying anything else. And I mean just the heater core...very narrow bars and piping can hold a lot of crap and restrict a lot of flow.
I did notice the bottom hose does not get hot. I had the flush done at Babcock in Rochester. I questioned them about exactly what they would do (they did not connect it directly to the heater core). They said they got the air out of it, but it took a long time. They did not hook up direct to the heater core, which I will be doing as suggested by Yusef. Once I drove it back from getting flushed (as it was getting hot) I parked in my driveway and looked under the hood. I saw it bubbling out of the overflow and I saw bubbles coming out of the top of the radiator (I took the cap off). It was consistent for about 5 mins until just after I shut it off. I took this as exhaust flowing into the coolant.
That is probably the case. Overheating due to air in the system from bad seal around the cylinders. I would buy oem turbo head gaskets when you get around to putting it back together. Subaru did have a campaign back then to put a stop leak substance in the cooling system to prevent head gaskets from failing...
Just got the heads back from the machine shop. The reported no cracks and they were not warped. They machined them and did the valves so now I can be confident that they are not going to cause problems. Tonight I will attempt to flush only the heater core and see what comes out of it. The only other thing I can think is that the block could be cracked somewhere.
I noticed this and No I didn't think to ensure this. Next time I put it back in I will be sure to face it forward.
I hope it works out for you this time! FYI you can use a Block Check/Tester kit to test for hydrocarbons coming through the coolant: http://www.importtuner.com/tech/impp_1108_blown_head_gasket_diagnostic/ http://www.napaonline.com/Catalog/C...ock-Test-Tools-Inc-/_/R-BK_7001006_0361139896
Flushed the heater core. I found that filling ti with water from the hose and the putting air through it worked best. Here is what came out. You can see that some of this stop leak is around the same size as the hose.
After cleaning out the heater core and getting the heads decked I dropped the engine back in. All seems well. I drove it around for about 15 miles and the temp stayed solid around 90C. (Previously just going around the block would get the car well over 100C) I can't say for sure weather it was the head gasket failing again or the heater core, but since the machine shop said the Heads were not that bad I'm leaning towards the heater core. If anyone runs into this problem one thing you can do is removed the heater core from the coolant loop and see if that helps overheating. If so flush it out or replace it. Thanks all for the help!
Another tip I've heard from folks troubleshooting coolant issues is if you suspect a bad thermostat, even if it passes the boiling water test, you can stick in a gutted thermostat (basically just the flow restriction with no valve) and see how it runs with that...
