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Head gasket blown after three months since replacement?! - 97 Outback 2.5


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Well, I've done it again. I think. Several times I drove it ten miles or so, overheated it, bled out LOTS of air, refilled it, then overheated it again (not too hot). Of course this got progressively worse then 100% terrible 37 miles from home. About to go out and do the compression test, but wanted to ask a few questions first:

 

  • Is there any chance this is NOT a head gasket?
  • What are potential reasons for a repeat blown gasket? Could there be some underlying problem that is causing too much heat? Something else?
     
    Assuming it is a head gasket...
     
  • The tow truck driver mentioned that some heads are fastened with stretch bolts. Should I buy new bolts?
  • Since I replaced all the seals three months ago, can I get away with just replacing the head gaskets? Or do I need to re-seal everything?

 

Thanks folks. :o

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If this is a repeat failure then it wasn't properly done or the block is hosed.

 

Properly done means Subaru only on the headgasket (for this engine), machined the heads, and cleaned the block and torqued properly. If all of that was done they should hold.

 

There are examples of blocks that can't hold a new gasket because of deformity of the block. It's rare, I haven't seen it happen, and probably happens in cases of really bad overheating. There are some Subaru dealers that replace engines rather than do head gasket jobs due to this possibility. It's overkill but it's dealers that have been burned - charge $1,500 for a repair that doesn't work. That doesn't make a happy customer.

 

These things overheat if not properly bled, so make sure that's been done properly. New radiator cap and Subaru only thermostat would be nice to make sure as well.

 

In stock form these rarely fail compression tests even when the headgaskets start to fail, so in that case a compression test isn't likely to tell you much. but being a replacement job it's probably more likely to be different than usual.

 

replacing the head bolts is not your issue, they aren't replaced in Subarus. he's not wrong since other engines require it, but he's wrong about Subarus.

 

no need to replace the seals you replaced. you'll only repair/replace things specifically head gasket related, like the head gasket.

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Drop in a 95 2.2 and be done with it!

 

I do this all the time, as it's cheaper, I feel I have a better product and there is not that much difference in HP.

 

I've seen may 2.5 that had the HG done only to throw a rod a year or so down the road.

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When I had my heads measured in November they were warped by .003". The spec was .002" so I went ahead and had them machined. I can't imagine that the block is warped if they were so straight. I followed the torquing procedure to the letter but it's possible I made a mistake due to the cheap hand tools I was using. I suppose it's possible that some type of debris landed in there but obviously I was trying to be careful. Granted I am a newb at this so it could have been any combination of the latter two, or the machinist messed up.

 

The 2.2 engine idea is a good one I think. Where's the best place to look for one? How much should a 15-year-old motor cost, and how many miles is too many?

 

Thanks guys!

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This time around it wasn't nearly as expensive as the last time since I didn't bother replacing any other seals. I got the heads re-milled on Friday because I was worried that the last machinist might have messed them up. I also BOUGHT A GOOD TORQUE WRENCH (the kind that clicks). On my list of things that may have gone wrong in the first HG job, using a needle-type torque wrench is #1. Finally, I should note that three of the camshaft cap bolts in the front camshaft cap (with the oil seal) sheared off when I tried to remove them. Most likely I over-torqued them when I reassembled a few months ago. Beware, folks, the front caps get less torque because the bolts are smaller.

 

I'm happy with the recent job. Blew on Tuesday. Wednesday I bought the gaskets. Thursday I disassembled. Friday I got the heads machined and found replacement bolts for my camshaft caps. Saturday I reassembled. Sunday I added fluids and started her up, then went joyriding through the country. Not bad for a newb working in the dirt without air tools. :)

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I sure hope youused subie gaskets. In my experience, repeat failures have been due to using non subie gaskets. I even did a few with "certified OEM" gaskets from another manufacturer and had all three come back in fairly short order. Once the gaskets were replaced with subie gaskets the engines ran like a champ and had no further problems.

 

Good Luck

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I'll let the myth perpetuate itself. I make a lot of money buying and repairing the blown head gasket cars. :)

 

Followed by cars that whoever did the timing belt job didin't tighten the crank bolt tight enough. I just passed on another one of those this past weekend. Have too many projects now.

 

Or generic plug wires on a 2.5.

 

They are pretty much bullet proof other than the HG's and stupidity.

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did you replace the o-rings that seal the crossover tube? It doesn't have to come out to do headgaskets, so alot of people overlook those o-rings. But I always do them. I have actually SAVED people from doing headgaskets a second time, just from noticing that there is weepage from around those o-rings.

 

Also, did you get replacement bolts for the cam caps? the front most ones are standard bolts, but all the others have a stepped shaft that fits snug into the caps and located them exactly. I've broken a few as well.

 

Overall, good job.

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  • 2 weeks later...
I sure hope youused subie gaskets. In my experience, repeat failures have been due to using non subie gaskets. I even did a few with "certified OEM" gaskets from another manufacturer and had all three come back in fairly short order. Once the gaskets were replaced with subie gaskets the engines ran like a champ and had no further problems.

 

Good Luck

 

How interesting. The first repair was done with those OEM gaskets from 1stsubaruparts.com and the second was from the local dealer. I sure hope that makes the difference!

 

Of course as soon as I start driving the thing again the brakes start to stick. If it's not one thing... :rolleyes:

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