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how to tell which head gasket is bad


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99 outback wagon. 

I bought it with bad head gaskets, blowing water out of the radiator. Changed the gaskets, and ran ok, but always worried me it was not quite right. recently did the same thing to me. 

I have a wrecked car, so moved all the components over to the engine, and it will not turn all the way over, so something in it is bent. 

Now I have this engine out of the car, on a stand. the leak down test does not put air in the cooling system. I get about 40 psi on all the cyl. using a ratchet. I have no idea what is up. maybe only leaking when hot? if so is it a cracked head? how do I tell. I really am at the point I feel like I am throwing good money after bad. trying to decide if I should replace both again, or just junk the car and move on. 

all advice and tips welcome. 

Thanks 

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Ok;  Let me see if I got this straight.    Your post is slightly confusing.

You bought a 99 with bad HG , you repaired it yourself and it worked for a while but now it has gone out again?

Then you have a different motor from a wrecked car that you want to use but it will not turn all the way over ? 

If your looking for a bad head gasket , remove the head and look at the gasket ...  you can always see where it blew thru.  cracked heads can happen if the motor gets hot enough.  Of course if it got that hot the rod bearings are next.

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sorry, it made sense in my head. as much as anything does... 

Yes you are correct. the engine from the wrecked car that i planned on using will not turn over all the way, so something is bent in it. 

So I went back to the engine that has the blown head gasket. which I have repaired before. I was trying to find a way to only do the bead head gasket, but I do not know which one it is. 

It is blowing water out of the radiator, so I thought if i did a leak down test, that it should leak into the coolant. but It does not do that. I guess I am just going to do them both again. last time i did not know i needed to have them machined, so I will do that this time. probably at home. i am really trying to keep the cost down, i have spent way more than I thought i would.

sorry i was so confusing.

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I would just resurface them with new OEM or equivalent gaskets on both sides and be done  

theyre notorious for having intermittent symptoms  I’ve seen them go weeks/months between overheating events - I would assume the weeks/months during no overheating would pass a leak down test and it’s likely load dependent or not a complete failure  

One of the plugs didn’t look differ did it?

You could pull one head and check it first - maybe it’ll be obvious it was that one and you can avoid the other side (fingers crossed)?

EJ22 swap?

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car ever set a misfire code? that cylinder's bank would be my best guess.

wonder if you could idle or even drive until system is bubbling, park and idle engine, then quickly pull and replace plug wires 1 at a time while monitoring the bubbles? when you kill combustion in the leaking cylinder, bubbles should decrease right? Or, killing the leaking cylinder would affect idling the least?

may need a helper to keep the engine running?????

 

Edited by 1 Lucky Texan
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maybe, but the engine is out already. 

I started changing the head gaskets. Subaru gaskets are $81 each. and not even gold plated. but i got those, last time it was fel-pro. 

What causes a head bolt to creak when finishing the tightening procedure? the last 90. yes i used motor oil on the bolts.

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Switch to engine assembly lube for head bolts, use no oil.  Grind slots in an old head bolt, fill with assembly lube and chase the threads.  Run all the bolts down the threads after chasing.  Replace rusted bolts.  Lube the top of the washer and the mating surface of the bolt head.  Leave engine side of washer dry.  

Edited by 89Ru
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so I have this one bolted down do I have to replace it?  can I just remove the bolt, (center intake side) and chase it and install it again. or just leave it.

What dealer are you using? the one in Vancouver Washington wants 80.99 each. i got to find a better dealer. maybe I can get them at a different dealer and return them to this one?

Here are the surfaces before bolting it together. I do have a spare bolt, so I will see if I can slot it and chase the other side. 

head.jpg

engine.jpg

Edited by whynot
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Any of the dealers in Portland..... our account is through Lithia Subaru in Oregon City. Subaru of America MSRP is 49.95 retail. 

parts.subaru.com

Gresham Subaru is good. Carr Subaru in Beaverton has largest inventory and lowest wholesale pricing for high dollar customers. I have been offered 33% off retail to do my business with them but the distance is too far and I get 28% with Lithia. Having that relationship 1 mile from my shop makes it much easier to run down between deliveries if we need something quick (pretty much a daily). 

If you haven't run it - just take it back off and chase the threads - retorque it with Amsoil assembly lube. If you can't find anyone up there that has it I carry the assembly lube here at my shop in Milwaukie. It's like $6. 

GD

Edited by GeneralDisorder
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so I can take the head back off, and use the same gasket again? never done that before, always had to change them. Just making sure. If I can then I will do that. 

Also how big of a slot in the bolt. I have a cut off tool, and a 4" hand grinder,

Thanks again.  

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I would put the bolt in a vice, and use the cut-off-wheel. Slot the threads 180 degrees apart all the way up the threaded section. Width of the cut-off-wheel, 3/16 depth or as close as you can. Try to keep the edges nice and tight and sharp. 

Yeah the gasket should be fine. It probably needs more torque than it got with the creaking bolt anyway. 

GD

Edited by GeneralDisorder
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another question. 

I used 220 grip paper to surface, is that good enough, or in an old post I found to use 220 then 320. I am taking it apart again, is it good enough, or hit it with 320 before going back together. 

Thanks again for all the help.

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We actually use a 150 grit cloth backed media. 

https://www.amazon.com/INDUSTRIES-4245-Emery-9-Inch-11-Inch/dp/B000BPNMZ4/ref=sr_1_cc_6?s=aps&ie=UTF8&qid=1541177698&sr=1-6-catcorr&keywords=ali+150+grit

We make two passes - the media sheers down to a finer grit so on the second pass it's much finer than 150 grit anyway. 

GD

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  • 2 weeks later...

back again. maybe I should start another thread.? 

  1. Got the engine back in. Very hard to start. but when started idles fine.
  2. Also have code p0117 coolant circuit low input.  can you tell me where to look for that?  if I did not plug something in, would that also relate to the hard start? 

Thanks

Doug

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so i found thee 2 plugs, the spade connector i found where it goes, the 2 pin one, i can not find a home for.  i assume it is one of the two you mentioned. going to go look again,, also on the crossover near the other one?

 

also, the alt. is not charging. does it go anywhere except to the battery? the bolted wire and the plug connection. 

plugs.jpg

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found them. man the one is right under the wires. hard to see hard to get at. working good now. 

Alt is putting out 10V, at idle. 14 if i rev the engine. so it is working. but maybe weak? or ok to leave on the car for now. 

 

Thanks so much, a few left to button up, then a drive.. 

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