sportsfan1026 Posted July 15, 2006 Share Posted July 15, 2006 97 OBW 2.5 AT w/ 98K Bought of E-Bay not running w/ know head gasket problem. Motor ended up being in fairly bad shape. Compete Rebuild of motor (Including machine shop work to have the heads done) Used a generic gasket set from NAPA (including head gaskets) Had to work through a couple of CEL once the car was running. (That’s when I found this board and learned about the infamous 2.5 DOHC) Car ran great for 3 months and 10K miles. June came and I started using my Air Conditioner Let my mechanic friend (the one that did most of the work on this car) borrow car for a long weekend trip. He brought It back and said that it quickly overheated once on him but it went back to normal never to move again for the rest of the trip. He told me to watch the Temp closely. I drove for couple of weeks with no problem. One day I was driving and noticed my AC had stopped working. Looked down and the Temp Guage was all the way to the top. (Possibly drove it 3-5 miles @ 50 MPH like this) After that Overheating begin to occur more often. Never slowly always in the matter of 20 seconds it goes from normal to the red For awhile it would only overheat when I shut it off warm and then started it with in the next 5 minuets. (getting gas, running in to the store ect) I was able to work around this and drove the car while I tried some obvious things (thermostat, ect) It has now started to overheat more frequently mostly when suddenly slowing down after being on the hwy for an extend period of time. It now has to cool down for at least 20 minuets before the cooling system starts working again. @ Idle and immediately after shutting off the car I have bubbles coming out of the overflow hose. No black stuff floating in the tank but I am sure that is coming. Car has now become un-reliable and I want to get it fixed ASAP Here is my diagnosis: I Need new HG’S (Good ones this time) But what was the original cause of the OH? I only had about 9K miles on the new (Cheap ) Head gaskets. I don’t know if they are the original cause of OH or if they failed due to the car overheating but they need to be changed. Because the one time I drove the car while it was in the red was enough to make my new HG fail regardless. My current over heating is occurring when under a load exhaust gas gets in the coolant and forms a bubble that then causes an air lock when I start the hot engine (or now when I slow down) I never cleaned or checked my radiator after the rebuild. And maybe it was full of junk from the previous HG failure. It kept up with cooling for a while. But when it got warm out and I started using my AC it was too plugged to work properly and this may have contributed to the original overheating incident. Please let me know if you agree with me. Is there any reason to hold off on removing the engine, and doing the HG’s again.? IF I change the HG’s for good ones, clean or replace my radiator. I should be in good shape, correct? If you have taken the time to read all of this I really appreciate it. and THANK YOU For all of your help. Quote Link to comment Share on other sites More sharing options...
2X2KOB Posted July 15, 2006 Share Posted July 15, 2006 I've heard it said, here and elsewhere, that trapped air in the cooling system can cause this. This is by no means a conclusive conclusion. Quote Link to comment Share on other sites More sharing options...
Setright Posted July 15, 2006 Share Posted July 15, 2006 HG failure, is pretty likely. Especially since it's overheated a few times now. Make sure you get the latest version from a Subaru dealer. They are silver, not black. (At least in Europe) When time comes to fill the cooling system, fill as much as you can directly into the block through the upper rad hose and then re-attach it to the rad. Fill as far as possible through the rad cap hole, then run the engine without the rad cap on and wait until the fan starts running. At this point you know for certain that the thermostat is open and allow air bubbles to circulate up and out of the rad filler neck. Top off the level in the rad, and mount the rad cap. It'll burp along the way as it heats up so have a cloth wrapped around the rad hole to catch the spillage. A new rad cap would also be a good idea. Quote Link to comment Share on other sites More sharing options...
Subie Gal Posted July 15, 2006 Share Posted July 15, 2006 Please, go get a hydracarbon test before you crack the block chances are, it's HG failure keep driving on it, and you'll need an entire shortblock replacement Jamie Quote Link to comment Share on other sites More sharing options...
nipper Posted July 15, 2006 Share Posted July 15, 2006 you said it yourself. CHEAP headgaskets. Subaru HG should be bought from Subaru. It takes time for engineering changes to get to aftermarket suppliers. Also Aftermarket suplliers will not pull off unsold stock to replace it with a redesigned part. Also you have baked the engine oil. If you keep driving it like this you will need an entire engine since youll spin a connectiing rod bearing. nipper Quote Link to comment Share on other sites More sharing options...
sportsfan1026 Posted July 17, 2006 Author Share Posted July 17, 2006 Is a hydorcarbon test something I can have done localy? Or do I mail it out. If so please give me recomendation to have one done. (perferably a site sponsor or something becasue this site is great and I really appreciate it) I realize it may be a waste of money but I would like to be sure before i remove my engine again. Also please advise a good web site to get some good OEM parts (sponsor again) Closest dealership is 300 miles away and they dont stock any thing. Thanks alot for all of your help. Ben Quote Link to comment Share on other sites More sharing options...
jasinwa Posted July 17, 2006 Share Posted July 17, 2006 Is a hydorcarbon test something I can have done localy? Or do I mail it out. If so please give me recomendation to have one done. (perferably a site sponsor or something becasue this site is great and I really appreciate it) I realize it may be a waste of money but I would like to be sure before i remove my engine again. Also please advise a good web site to get some good OEM parts (sponsor again) Closest dealership is 300 miles away and they dont stock any thing. Thanks alot for all of your help. Ben A good soobie mechanic (dealer or not) will be able to do the test. They measure the HC coming out of the radiator... I think on this site there is info on it. There are kits you can buy also, to test yourself... Check this link out for my local soobie guy... Click me "If you don’t have the luxury of a 4 gas analyzer you can purchase an engine block leak detection kit from your local NAPA autoparts store. Part Number 700-1006 for under $50. This kit uses a fluid that changes color when it chemically reacts with coolant containing exhaust gas." Quote Link to comment Share on other sites More sharing options...
dxrflyboy Posted July 17, 2006 Share Posted July 17, 2006 Your heads may also be warped. You didn't specify whether or not they were resurfaced during the rebuild. They must at least be checked for flatness and machined if necessary. Quote Link to comment Share on other sites More sharing options...
sportsfan1026 Posted July 17, 2006 Author Share Posted July 17, 2006 The heads were faced at the time of rebuild but I will check them again. I am also concerned that my problem may not be a head gasket but a cracked head or block. Since my head gaskets were changed 10K miles ago and are allready gone. I had the heads checked for cracks when they were done at the shop but is supose they could have missed a crack? How can I be sure that my problem is really my head gaskets?? Thanks for all of your help Ben Quote Link to comment Share on other sites More sharing options...
tunered Posted July 18, 2006 Share Posted July 18, 2006 Let me say first that i am no expert, come from the old school. A blown head gasket should repeat the same symptoms time after time, not come and go. i have seen low coolant level do the exact same thing, including bubbles, trying to release the trapped air in the system. a simple pressure check should reveal any leak the system has. ed Quote Link to comment Share on other sites More sharing options...
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