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EJ25D Heads: Nothing Looks Wrong To Me


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Your headgaskets were at the beginning of failure, plain and simple. No doubt about it, especially after looking at the seal rings on the gaskets. The clean-ish part is where they failed.

 

When they fail, compressed gases leak through and super heat the coolant. Hence, the overheating and smell of burning coolant. When the gaskets first start to fail, the overheating will not happen every time you drive and it won't always be very bad, and it might only be heated enough to the point you only smell burning coolant.

 

This is the stage your car was at. As it gets worse you overheat more and more often and you lose more and more coolant and it overflows right out of the overflow reservoir. This is the ONLY way you lose coolant. You do burn some coolant, but hardly any whatsoever.

 

Your gaskets are the OE gaskets and are not graphite.

 

The black crap in your overflow reservoir is some carbon build up from the hot gases escaping the chamber.

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Your headgaskets were at the beginning of failure, plain and simple. No doubt about it, especially after looking at the seal rings on the gaskets. The clean-ish part is where they failed.

 

When they fail, compressed gases leak through and super heat the coolant. Hence, the overheating and smell of burning coolant. When the gaskets first start to fail, the overheating will not happen every time you drive and it won't always be very bad, and it might only be heated enough to the point you only smell burning coolant.

 

This is the stage your car was at. As it gets worse you overheat more and more often and you lose more and more coolant and it overflows right out of the overflow reservoir. This is the ONLY way you lose coolant. You do burn some coolant, but hardly any whatsoever.

 

Your gaskets are the OE gaskets and are not graphite.

 

The black crap in your overflow reservoir is some carbon build up from the hot gases escaping the chamber.

 

It seemed like I was always low on coolant... Not a ton, but enough to notice. The new gasket set I bought was the Felpro MLS Headgasket set with all of the other gaskets included (for about $200). I looked up the torque specs for this specific HG set and will be abiding by those, rather than the Haynes book which only gives specs for dealer parts (bastards).

 

When you burn coolant, there are 2 key things to look for. The exhaust always comes out white, because its steaming. The second is that it will smell sweet. If you're loosing coolant, and don't see it dripping anywhere under your car when you park in a clean/dry parking spot, then it has to be going somewhere right!?

 

Your pics show some greasyness on your valves. Are you adding a lot of additives? perhaps thats where the fluid is going. If your rings are good, then you won't notice any coolant in the oil, as the leaking coolant is just going straight out the valves, thru the hot exhaust and evaporating it. You should notice an extreme amount of water coming thru the exhause at start-up.

 

Did you do a compression test before you tore apart the engine? Always a first step! What about the timing? You need to verify things are right before you go and tear apart the block. I do agree, that head gasket looks F'd! Take the heads in, get them checked. No point putting them back on if there's a chance they're warped..

 

Cheers

 

I'm PRAYING that my rings are good and my block is square, cuz I'm NOT taking that shit apart... I bought the car less than 1k miles ago. It was almost due for an oil change when this blew up. I highly doubt there were any additives in it, but I can't be positive. I didn't do a compression test, but I did mark the timing on the new belt before I took it all apart. I bought a Haynes book and verified everything I did before I did it.

 

Why is a compression test so important? To identify which cylinders are the problem areas? My mechanic kept asking me if I did one, but we never actually did one before we took the block apart. I should do one once I have the engine back together right?

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Thats why you do a compression test first. If your #'s are low, then you know there's somethings wrong. Then, once you start taking it apart, you look for things, ie: timing off. If the timings fine, then you're looking for mechanical failure, such as rings, pistons, cylinders, cams, valves, springs, etc! Its hard to guess, but first hand is easy to see.

 

Your engine overheated, once? Twice? more? The problem with aluminum heads on an Iron block is that they expand differently, which is due to different metal characteristics. Aluminum dissipates the heat a lot easier, so they expand slower. When you over heat an engine, the iron will expand faster, and being the 2 are bolted tightly together, the Iron block pulls and stretches the Aluminum heads. A compression test is one simple step to a proper tear down and rebuild. Plus with the threat of washing the one or more cylinders with the coolant, you might have to at least get the cylinder walls honed - if not bored out and getting some over sized pistons.

 

There are a lot of other things you can do first, such as reading the computer with a scan tool, but at least when you get it back together, you should be able to salvage most, if not all the new gaskets after you do some of these tests... Its fun to do! Enjoy!

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I think what honestly happened was this: The dealer overfilled the oil (as it was overfilled when I got it). I didn't do an oil change because I couldn't get the oil pan plug off. I figured it couldn't do much, but with a high compression engine with bad gaskets, it's only a matter of time before crap goes wrong. Anyway, too much oil = too much oil pressure. When I started draining the oil, it had almost 7 quarts in it. I thought I smelled coolant in my oil, but coolant floats and there was none on the (oil) dipstick when we checked it. When I drained it, it just looked like normal oil that had been just about used up.

 

So I had bad gaskets with too much oil pressure out on the highway for 45 minutes straight. Disaster. To be fair, I didn't take it very easy on the car. The combination of my driving habits, the unscrupulous auto dealer, and the OEM gaskets was just too much.

 

Does this sound like a plausible scenario?

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Oil pressure will not increase with volume. It is generated by a specific flow of the pump and restrictions in the oiling system.

 

Like Kenny has said, your head gaskets were and are showing signs of failure. Have the heads re-surfaced and slap them back on with new MLS gaskets. Was it overheated for a seroius amount of time?

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Oil pressure will not increase with volume. It is generated by a specific flow of the pump and restrictions in the oiling system.

 

Like Kenny has said, your head gaskets were and are showing signs of failure. Have the heads re-surfaced and slap them back on with new MLS gaskets. Was it overheated for a seroius amount of time?

 

Yeah if the engine was overfilled with oil, the worst that could happen in your case is oil would flood the engine (would get into your intake system and be burnt, causing smoke from the exhaust system) because the oil would froth up from the crankshaft beating the oil as it turned, filling up the crankcase and pulled through vacuum lines. That would cause bearings to fail. This obviously didn't happen to you, and it most definitely does not happen often. You would have had to massively overfill it and driven quite far.

 

Those gaskets look like any other gasket that I've seen where the gaskets have failed. And increased oil pressure would not cause the gaskets to fail, especially in the way they did according to the head gasket. Plus, overfill usually causes pressure loss.

 

Your car seems to have not been driven very far during any overheating, so honestly, your heads are more than likely perfectly fine.

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Well guys, I'm not sure that I understand the "danger zone" of overheating very well... It overheated enough to kill the engine, I pushed it to the side of the highway, and then I had to drive it off of the highway. I never let the needle touch the "H" after the initial heat up though, so I figured that the heads wouldn't be that bad. The whole process probably took about 10 minutes of total running time over the span of a few hours.

 

To be on the safe side, I'm going to have the heads resurfaced to make sure the gaskets get a good grip. I have a couple questions for when I get it back together though:

 

-What kind of oil should I use?

The car is at 175k miles. I live in Colorado (around 5k feet above sea level).

 

-What's an equal alternative to Subaru's coolant additive for the EJ25?

I talked to a tech about my gaskets. He told me Subaru makes a coolant additive that essentially helps prevent coolant leaks in the system. I can't remember what alternative he told me to buy, but I remember him saying that there's a couple out there.

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If the temperature was elevated, but not at H, I don't forsee any damage. It's an easy check though - just measure the squareness with a straight edge.[/Q]

 

For the initial overheat, it was slammed far past the "H" on the temperature. I let it cool down to normal operating temperature and it was sailing between half-way and "H".

 

I'm going to get the heads milled right now. Should I get the block checked too? What are the odds that the block isn't square because of this incident?

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Well i'll see how warped the head was. If they take off too much material, it probably won't be worth salvaging the block anyway. I might take a look at an EJ22 that I could probably get for free, but it's been sitting for idk how long so it's probably rusted and needs new bearings.
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