98 Subi Forester - time for headgasket

Hello everyone, Are you still out there? Cigroller, Honda Blackbird, OK4450, anybody?? I feel like the guy that hasn’t been to the doctor for a while, and is wonderin’ if the doc is still practicing…

I got a 98 Subaru Forester L, 2.5, manual trans, 120k miles with a blown headgasket - imagine that? I’ve decided I’m going to fix it myself this summer. I’m quite capable and I’m enlisting my nephew, although he doesn’t know it yet. Got a few questions for the experts:

  1. Do you think I’m crazy?
  2. Is there a difference between a $150 gasket set and a $250 one - other than the obvious?
  3. It appears only one side is blown, does that mean I might not need to machine the other head?
  4. Head machining - I’ve seen these u-tube videos of guys using a hand stone and mineral spirits- is that for real?? If not, can you give me any ballpark on what I should pay a machine shop? I mean, I’m gonna go checking around, but I don’t even have a clue.

Thanks for any and all help.

The advice might vary a bit depending upon the situation. You describe the head gasket as blown which normally means it completely gave up and led to coolant into the combustion chambers which means smoking, engine oil mixing with engine coolant, etc.

The other side of this would be if the head gasket is simply leaking externally or weeping a bit.

I’m not sure about the difference in prices, but I prefer “Felpro” gasket sets when I rebuild an engine. There may be more expensive ones, but I’m more interested in the quality than if they are cheap.

I’m not sure if it is an easy job on a Forester while it’s still in the car. I did two Foresters with my buddy, but we pulled the engines to do them. We also replaced the timing belts on both and all the related parts.

As far as resurfacing one at home, it’s a gamble weather or not you’ll get the head flat enough.
All that work and it blows again in 6 months!!! I’d rather pay the machine shop to do it right,

Because you mentioned it I looked up some Utube videos on the subject and I wouldn’t trust any of the ones that I watched. They say it works, but they will never tell you about the ones that didn’t.
Everyone wants to be a movie star!!!
I’ve seen a lot of inept people in these videos.


You have to pull the motor. Not impossible but a lot of steps and time without experience.

Do you have a Haynes manual? It’ll spell out the steps. And have a pro surface both heads, cheap insurance.

Are you crazy? No, but I’d say hopelessly optimistic. This is a major professional job and I wish you luck and lots of available time.

Howdy, Gentlemen, I’ve got a '99 Forester and just replaced the head gaskets (and used the opportunity to be sure everything else was in order while the engine was pulled). I swear by my Independent Authorized Subaru Mechanic - and can tell you the professional machining was surprisingly inexpensive.

Use the opportunity you get by pulling the motor to check all those things you can’t get to whole it is in place. Like the A/C. We did the 300,000 mile check and I’m pretty sure I’ll get another 200,000 miles out of the beast.

Keep us posted on how you do, and what you find. (I keep telling the guys I want to learn how to take one apart and put it together again… the images in my head aren’t enough fun anymore! )

It would be ill-advised to expend time and money in a head gasket replacement without considering the reason for the failure or a little diagnostic before tearing things apart.

Many have gone this route and ended up with a problem child for their efforts.

ok, yeah your’re right, I should say what is happening with the engine. The 1st symptom years ago was occasional coolant blowing out into the overflow, due to air/gas/exhaust/??? getting into coolant. Then it started…I guess “weeping a bit” on one side pretty much describes it. No real serious steam pouring out from under the hood, but the coolant loss got constantly worse until the car was undrivable. Never saw any sign from the tailpipe. The worst the car has ever run is maybe a little rough at times.

yosemite, I agree, I’ve liked and used fel-pro gaskets for awhile, and I’ve seen sets going for $150-$160, but there are sets out there for $220-$240 that claim to be better for this damn headgasket-blowin engine. That’s what got my attention, because in my mind, this engine has a design flaw, and it’s located somewhere in that tiny slice between the head and the block.

This is just my 2 cents, but I don’t consider Subaru head gasket problems a design flaw so much as a process flaw. If head bolts were retightened after some time in operation (say 500-1000 miles) odds are these problems would never surface and yes I’m fully aware of the “doesn’t need it” statements to the contrary.

The heads should be checked with a straightedge for warpage. A couple of thousandths is allowable. If severely warped they need to be machined flat or the DIY method of a large file or emery cloth on tempered glass method. The latter methods can be time and elbow consuming.
Valve leakage is checked and high miles heads get a valve job.

I always replace valve seals and check lash whenever the heads are removed.

I always spray the head gaskets with aerosol Copper Coat. Head bolts are tightened and the engine allowed to sit for a while; preferably overnight. This allows the gaskets to relax so to speak.
Retighten the head bolts and odds are you will find they have loosened overnight due to gasket crush.

That’s the short form of how I do it and it’s never failed me.

The reason I asked about why the gasket failed is that I run a compression test before tearing it apart. A badly overheated engine that has piston ring/cylinder issues can become a real problem if new head gaskets are installed so the compression test is a heads-up to possibly stop the process before it begins.

Coolant going into the overflow could be due to an iffy cooling fan, weak pressure cap, balky thermostat, etc. A head gasket job should also mean an oil change and new thermostat.
Hope that helps in some way.

@ok4450 the head gasket issue is a above average occurrence with the 2.5L non turbo EJ series.

The process will help potentially but the motor is flawed as the 2.2L ej, 2.5L ej turbo, 2.0 EJ, ej 1.8 never had any real issues with head gaskets. The motors have a lot of similarities as they are like legos somewhat to each other.

I ask this in a respectful manner in regards to the faulty engine block theory.
Who says?

ok, thanks, that’s all good advice. I can say the coolant blowout is not the cap, the thermostat, or the fan. I can actually see air/exhaust/whatever bubbles coming to the surface (looking into the radiator cap hole) or when capped, looking into the overflow and I remember thinking (when this all started) that the coolant smelled like gas or exhaust. I’ve never seen any bad signs in the oil or out the tailpipe. Under the hood, the drivers-side head (bottom edge toward the firewall) is where steam appears to come from. All these symptoms and talking to people have led me to say the engine has a blow head gasket. I’ve never confirmed it any other way. Would a compression test be a good idea? Do you think it’s a blown head gasket?

Do you think it's a blown head gasket?

No doubt whatsoever.

If you want to be more certain, use a block tester to confirm combustion gases in the coolant


from the sound of things, the fluid will turn yellow in a hurry


I believe you should do both head gaskets at the same time, even if you’re absolutely certain only 1 of them is bad. Straightedge the heads and block. My opinion is that if they’re straight within specs, don’t mill them just to mill them. Why remove material if you don’t need to?

I’d add a careful inspection to see where the exhaust gas was leaking. That could require milling, even is th head is flat.

Yes Yes the doctors are indeed IN. Sorry I was doing a Proctology exam on a Blazer… Anywho…NOOO your not crazy…this is right up my alley actually.

This is a GREAT Vehicle that has been let down by a faulty head gasket DESIGN and also they are let down by the fact that its IMPOSSIBLE TO RETORQUE the Head Bolts as the engine ages. Subaru has admitted a gasket design problem tho who knows the real culprit. Heres what you do…YANK THE ENGINE…Those engines come out in a Jiffy…My current record is 35 minutes working alone…

Then pull the heads…have a machine shop check them for level and if they pass they pass…if not have them cut until they are nice n flat. I usually pay about 100 for a mill job about 150 for the two Subi Heads cause they “Cut” me a break…they know I will return in time. THEN…go to Subaru themselves and buy the UPDATED AND IMPROVED head gaskets and go to town. I would also of course do the FULL timing belt service at that time as well and then drop her back into the vehicle. Ive done 5 of these so far with the Subaru gaskets and a mill job and havent seen problems yet…then again…I would imagine only 40K could have been accumulated. I hate to hear that there may be a block design issue like Andrew mentions…Jeezu I hope not. I thought I had this licked. I do also use a dot of Lock tite on my head bolts…yeah a no no so sue me.


Blackbird, Thanks, good to know you’re still around. You know, I kind of thought the same thing, it doesn’t look to daunting to me. But you must have done a few of these to knock it out like that.
Yep, I plan to do the timing belt/water pump and R/R the clutch too - I figure what the heck, I’m already in neck deep.

Indeedy you will be neck deep… But this is the fun stuff. I think you can handle this no problem. I have to admit I am a bit worried about this inherent block problem I believe Andrew mentioned. I dont even want to think that is an issue…certainly makes me want to investigate it tho. I have indeed done several of these and nobody has returned with any problems since I put them back on the road so…I dunno.