'98 Legacy Outback blown head gasket? Spark plug analysis, CEL, comp test etc...

[annointed]

I just bought a '98 Legacy Outback Ltd (DOHC EJ25/5mt, 137k miles), with what the owner told me was a blown head gasket (coolant is empty, engine gradually overheats, and the heat blows cold, etc). I plan on using the car to do an EJ257/6mt swap, but first I want to get it up and running in stock form, get it inspected, registered, etc.

At any rate, I just recieved the car from the shipper last week, and my replacement head gasket from subaruparts.com arrived on Monday. Today I pulled the plugs expecting/hoping to find a "steam cleaned" plug or two. Instead, 3 of the plugs look fairly normal, with a considerable amount of charcoal deposit, but nothing really out of the ordinary. But cyl #2's plug is drastically darker, particularly on the threads, on the metal at the base of the threads (where the ratchet/wrench grips to install/remove the spark plug), as well as the upper section of the porcelain extension that the spark plug wires connect to. I took several pics (phone digicam, so forgive the quality) of the plugs that hopefully show enough detail to be of some help.

Anyway, at this point, should I rethink the head gasket problem? It still sounds like the best diagnosis. I noticed the car had a CEL when I drove it the half mile to my house from where I picked it up from the shipping truck. It starts fine and drives smoothly. I have OBD2 software on my Palm, but the Palm's battery just died, so by friday I'll have the new battery to pull the code and see if it sheds any light on possible problems. Until then I don't want to disconnect the negative terminal on the car for any reason, as I would like to see the CEL(s). I also plan to do a compression test to see what kind of results I get. Finally, I'm thinking I should probably just re-fill the coolant, and run/drive the car and see how long it takes for the coolant to drain and/or the temp gauge to rise beyond normal levels, rather than just go on the owner's word that its a blown head gasket.

I should have the pics hosted later tonight, and I appreciate any insight from my fellow nasioc'ers.

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[annointed]

[Diz]

From the pictures, the gunk on the #2 plugs has a reddish tint to it. It almost looks like ATF. That usually happens to #1 if there is as PS leak at the pump. Do you notice anything unusual on the deck?

[annointed]

Ok, got my Palm up and running again, and pulled the codes:

P0400 Exhaust Gas Recirculation Flow
P0420 Catalyst System Efficiency below threshold
P0483 Cooling Fan Rationality Check

I would assume that only the 3rd code really relates to the head gasket. I forgot to check Freeze Frame while I was out there, so I'll have another look in the morning.

[annointed]

Well, finally had a chance to compression test the car over lunch, since work has been so busy that I haven't touched the car in 2 weeks. Unfortunately, the engine was completely cold, as I didn't want to re-install all the spark plugs to warm it up, then pull them all back out to compression test

Cyl 1: 218
Cyl 2: 204
Cyl 3: 198
Cyl 4: 210

These numbers were way higher than the 140-175 psi that I expected (maybe I'm just used to low compression WRX engines?), but at least they are all within a 10% window.

I'm starting to wonder about the blown head gasket, as neither the plugs nor the compression test hint at a blown gasket. The engine oil is also clean and normal looking.

On Monday I think the next step is to replenish and bleed the coolant system (it was empty when I recieved it), and let the car run, and see if it still overheats, or if its drinking coolant. Maybe its even as simple as an external leak in the coolant system somewhere, although I would think the previous owner would have thought of that. At this point I've been going on the previous owner's word that it overheats and heat blows cold in the cabin due to a blown head gasket, but I haven't taken the time to personally verify either...seems like a logical next step.

Any thoughts and insight are appreciated.

Mark

[annointed]

Not that anyone cares, but I had some time this evening to refill and bleed the coolant system on the Outback. The car runs superbly...smooth as silk...I cleared the CELs, and plan to register/insure the vehicle tomorrow morning. That will give me 14 days of street usage before I have to get her inspected by the state. If no codes pop up in the first 7 days, I'll probably take it into the state for inspection next Monday. This should also allow me to moniter whether or not the car drinks coolant, since I log 800-1000 miles/week for work...better believe I'll be packing several gallons of distilled water in the trunk to play it safe

As for tonight, I probably had it running for at least 45 min tonight, with at least 5 key on/key off cycles...no codes reemerged, and nothing unusual in any way, so we'll see what this week holds

[annointed]

Well, my pussyfooting around with this car continues...I always have been a procrastinator, but now it looks like at least one of the heads has to come off

I put the car on the road yesterday (my 27th birthday, ironically), and last night I drove 2 miles away to get gas...the attendant asked if my car was running hot, saying he felt heat from it when he filled the gas tank (I'm in NJ - full service required)...I was like I thought maybe the jdm Legacy b4 wheels were rubbing the rear struts, since clearance was tight, but they were cool to the touch...the car was somewhat hot by the gas cap, but it had cooled off by the time he mentioned it to me.

By the time I was almost home, the temp gauge decided to shoot for the stars....I put the heat on full blast, and made it home with the gauge nearly maxed out, and my obd2 scanner saying coolant temps were 244 F.

So much for no problems. Just to make sure it wasn't just air in the coolant system, I spent an hour and a half feeding it coolant and letting it gradually burp out any air...the coolant temps won't drop below 205 F at idle w/heat off. With heat on high they'll come down to 190 F and the fans will shut off, but as soon as you take it for a drive, the temps will gradually rise again to 225-240 F within minutes.

Today I drove the car, let it start to overheat, then pulled the plugs and did a warm/hot compression test to see if the numbers were any different from the cold test I did the last week...I'll put last weeks figures next to this weeks for easy comparison:


------cold-hot
Cyl 1: 218 213
Cyl 2: 204 209
Cyl 3: 198 218
Cyl 4: 210 210

Both with the cold and hot tests I actually did 3 tests of each cylinder, so I'm pretty confident in the numbers. The only thing noteworthy is that cyl 3 is 20 points higher when warm...so I'm going to start with that head gasket (right side). I'm tempted to just do both gaskets, though, since by the time I have the manifold, timing belt, motor mounts off, and engine jacked up, I may as well replace the left side as well, just to be safe.

If I can get up early tomorrow, I'll get this started, since I only have 14 days to get it inspected...

[annointed]

Ok, time to bump this thread. Winter looms, and I need my Outback up and running

I had a RARE day off today, and starting last night, a buddy and I pulled both heads from the car, and to our surprise, there is no clear sign of head gasket failure on either side

I'm taking the heads in to be looked at for cracks/warpage on Monday.

The front head studs were noticably looser than the rears, so its possible that coolant was seeping somewhere due to insufficient tightening, although that scenario is unlikely.

Any advice is appreciated. Unfortunately, I am replacing two of the camshaft gears (to the tune of $100 each) that were abused/damaged during removal (what kind of special tool is needed to get those suckers off???).

Needless to say, I'm a bit discouraged, as I was positive this was a routine head gasket problem, but now I'm not so sure

Assuming the heads are fine, my only hope is to put in the two new head gaskets, reassemble the entire thing, and hope that somehow the problem is fixed. I won't have time to start putting this back together, as I work non-stop, until next Thursday. Any insight is appreciated.

Mark

[annointed]

Bump for any thoughts from the weekend crowd...

[Patrick Olsen]

I agree with you that the indications certainly sound like a head gasket issue. Did you do the "simple" cooling system fixes first - new thermostat, new radiator cap? When my head gaskets went the first time I replaced those two things first, but then the car continued to overheat if I pushed it at all, so at that point I let the dealer take a look at it.

I could be wrong, but I thought the leak-down test was a better indicator of head gasket health?

Oh, the other thing worth looking at is the water pump. With that said, one would think if the problem was related to any of the 3 things I've mentioned it would rear its ugly head more consistently, rather than only every once in a while.

Pat Olsen
'97 Legacy 2.5GT sedan (blown the gaskets twice, but hasn't happened again in over 70k miles)

[Devan M]

I would say your heads are warped. Your head gaskets are made of metal so they cannot "blow" like the organic type.
The new gasket that Subaru provides for your motor has been re-designed from a three piece to a five piece gasket because of the problems they had with the old gaskets.

My dad uses an old timing belt to wrap around the timing gears to get the bolts loose!

[EastsideLegacy]

try checking the timing i had a similar problem and it was the timing....

Good luck main

[linsavy]

Sounds like the classic blown headgasket issue to me. Your heads are likely warped.
Cause is air pockets in the top of the engine, leading to overheating and warpage. Car then pukes coolant out of the overflow and temp soars.
Check all your pistons for slap while you have the heads off. This is another common unrelated issue that you may wish to fix while things are out.

[annointed]

I just dropped the heads off to a local shop to have them cleaned, checked for warpage, and possibly refinished.

We noticed that one of the cylinders does indeed look washed clean, and that you can see the coolant chamber that was leaking the coolant into the cylinder. The machinist said that the head didn't look bad from a glance, and pointed out that there was only one small spot on the head gasket that showed overheating, so I'm crossing my fingers, and hoping everything's going to be alright.

Hopefully Thursday my new cam gears come in, and the car goes back together with new gaskets...

Thanks for the continued feedback!