Anyone experienced with subaru head gaskets?

I picked up an 03 forester for my partner a month or so back. We got it for a great price knowing it was using a bit of coolant.

The radiator looked a bit suspect around the upper tank seal, and proved to be very suspect when the top tank split whilst doing a short drive to see how bad it was actually leaking.

After replacing the radiator, it's still using a minute about of coolant, and a pressure test has revealed a small leak at the thermostat housing. I'll be fizing that in the next day or two, but it may also have a tiny leak along the left head gasket which also appears to be weeping oil.

So basically I get the feeling head gaskets are going to be unavoidable and wanted to see if anyone here could offer any advice regarding their replacement.

Not having much experience with Subarus it looks very well set out in terms of being pretty easy to work on, the radiator was one of the easiest I've ever changed and the engine looks pretty easy to pull.

Load me up with knowledge please folks.

I have never seen a Subaru head gasket leak coolant externally. A coolant leak on the bottom (exhaust side) of the gasket is impossible since the oil drainback takes up 100% the length of the engine. There is no coolant passage there.

The water pump IS there, the thermostat bolts to it.

A lot of times an oil pan gasket leak is confused for a head gasket leak. This is why, as a personal policy, if the heads are coming off, the oil pan is going to be pulled and resealed as well. It's a piece of cake with the engine out.

edit - and "Engine out" sounds intimidating but it's actually quite easy, especially on a nonturbo model.

Subarus are weird in that the stuff that is difficult on most vehicles (like head gaskets and timing belts) is easy, and the easy stuff (like sparkplugs) is hard. Seriously, remove a few bolts and the engines practically fall out of a Subaru.

Thanks knurled, that's some interesting info, and that small drip further back on the engine may well have traveled from the t/stat housing given that the car was parked on a slight incline. The sump appears damp and so may well be part of the problem. I'll be cleaning and degreasing the underside when i do the t/stat leak which will allow me to better monitor what's leaking where.

The ej25 looks like a pice of cake to pull compared to most FWD cars so that doesn't worry me. But I also don't want to pull an engine and do head gaskets if it's not necessary.

Yup, change the head gasket. Get the subaru gasket unless you are literally broke and getting your food from a soup kitchen. The sohc 2.5 is super easy to swap timing belt and gasket. Don't forget the ground wire by the pitch stop. You can unbolt the power steering and ac from the block and zip tie them out of the way. You don't need to disconnect the lines. And I would remove the radiator so you don't bugger it up with the oil pan. There are other thing if you have an auto, but those are the main things that come to mind.

They'll happily leak oil forever (a friend has one that is now leaking bad enough he no longer changes the oil, just the filter), but if you want it be dry, it seems to me that you've gotta pull the motor, take it down to a short block, and reseal everything every 100k or so.

NickD wrote: Subarus are weird in that the stuff that is difficult on most vehicles (like head gaskets and timing belts) is easy, and the easy stuff (like sparkplugs) is hard. Seriously, remove a few bolts and the engines practically fall out of a Subaru.

I would not have thought this at all until I pulled one and wow... Easy as hell. Like yank motor to change the plugs easy.

A friend has had amazing luck with the Subaru brand head gasket in a bottle on two separate cars FWIW.

So a couple more questions then.

I've heard from a few sources that if replacing head gaskets on the ej engines that it's a good idea to go to the MLS hg from the turbo engines?

I've heard about the Subaru gasket conditioner, but would have assumed it's more of a bandaid than anything. Does it actually have any merit or like most chemweld type things am I just making more problems for myself?

Also, for those of you that have pulled subie engines, how long did it take? Looking at it, I'm thinking it could be done in a couple of hours tops...?

Cheers for the feedback so far.

In reply to Ross413:

If the engine comes out, long life spark plugs will probably go in

I did mine (01 Legacy Automatic) with the engine in the car. If you loosen the mounts you can swing the engine side to side for the clearance you need to pull the bolts out. I used subaru head gaskets, felpro for intake and exhaust, and a gates timing belt / water pump / pulley kit. That was... almost 40k miles ago I think.

I made a similar thread: https://grassrootsmotorsports.com/forum/grm/diagnose-me-leaky-subaru/41886/page1/

And one from Woody, which you might learn from, if yours is also automatic and you pull the engine: https://grassrootsmotorsports.com/forum/grm/the-dreaded-subaru-torque-converter-situation/92399/page1/

I have never had any issue doing plugs in Subarus.

It's not like they're 307-engined G-bodies, or Mopar RB-engined anything. And I know of one F-body that WILL need the engine removed if the #7 sparkplug needs to be changed, due to the header design. And I may be able to get an EJ25 from driving into the building to oil pan on the ground in 60-70 minutes but dropping a 4th-gen's engine is four hours minimum.

SOHC EJs are cake. DOHCs are a little tricky but not bad. The new 3.0/3.3 sixes kinda suck a little but also not bad compared to many other contemporary vehicles.

I could do the plugs on my EA82-engined Subaru with a three foot extension, standing up next to the car

In reply to daeman:

Get the Subaru mls gasket. The "gasket conditioner" is recommended by the factory for a new headgasket, but you don't have to put in more when you change your coolant (which we all change regularly....right?). I can pull a Subaru engine in well under an hour, but I have done it a bunch of times. Don't worry about the plugs, I can't see your engine but assuming you have the sohc they are on the top of the valve cover and real easy to change. The external oil leak on the head gasket arent a death knell for the engine and as long as the oil is kept topped up I imagine you could drive for years with no problems. It would drive me nuts to have a car that has an unfixed need, but that's just my quirk.

When people complain about Subaru plugs they are talking about the dohc plugs which are horizontal. First you unbolt the coils and then you pull the plugs. For that all you need is a 1/4" spark plug socket on a short extension which you put onto the spark plug without the wrench. After the socket and extension are in place on the spark plug you put on the socket wrench and break the spark plug loose. Then just take off the socket wrench and unscrew the spark plugs by hand. Vastly easier than a bunch of other cars that require cowl removal or other more involved processes. I personally use copper plugs because I was given a bunch of them. I change them every year or so when I change oil and it works fine.

I've only done Subaru head gaskets once, on my 2005 Legacy 2.5i. I spent a whole week on it, but I lost a few days when I messed up the input shaft on the automatic transmission as Mikeatrpi mentioned.

I screwed up

Removing the engine was actually pretty easy. I thought about trying to do the head gaskets with the engine in, but I wanted to get the block surface cleaned up and that would be nearly impossible with the engine in the car.

I didn't have the heads machined. I very carefully wet sanded the heads and the block mating surface with a new sanding block.

It's also a lot easier to do a valve adjustment with the engine on the stand.

There's some good info here, thanks very muchly guys.

A bit of an update for now.

I Replaced the thermostat, bypass hose and thermostat gasket on Saturday morning. Did another pressure test, it was still creeping down from 1.2bar down to 1bar. Had a bit more of a look around, found a small leak at the heater hose bleeder, which I stopped by tightening the hose clamp. I repeated the test, and have found a small leak from one of the throttle body coolant hoses.

Looks like I'll be replacing the heater hoses and tb hoses and retesting again. So far, no sign of head gasket coolant leakage which is a great sign.

I pressure cleaned the underside of the engine and will do a little more hand cleaning of areas that I couldn't reach with the pressure washer and then monitor the source of any oil weeps/leaks.

While I know in the long term I'll probably end up doing the head gaskets, it's looking like I might be able to put it off for a few months while I deal with a few more pressing issues.

I wouldn't do the head gaskets just for the hell of it. If they are only drooling a little oil, it can wait until it is time for a new timing belt or clutch. (Doing the clutch is way easier by pulling the engine vs. pulling the trans, especially if you live where things rust. A LOT of fasteners that need to come out for a trans pull simply won't.)

Obviously if they are mixing coolant into the oil, that needs to be addressed ASAP. This is relatively rare compared to the external oil leak issue. Most people wait until the engine needs out for other reasons, or if the oil leakage is so bad that it causes smoking from getting onto the exhaust.

My parents '02 Forester had external coolant leaks around the headgaskets at around 85k miles. They kept driving it until the temperature gauge started to spike. I pulled the engine and replaced the gaskets with the felpro MLS gaskets. If you're HGs are legitimately bad the smell the that comes from cracking off the head bolts is one of the most disgusting smells you'll ever smell. Which head gaskets are actually better, the felpro gaskets or the improved subaru gaskets?

I've used both, never a problem with either.

Follow the torque sequence religiously. Sing the Hokey Pokey while doing it, you'll feel better.

You torque the bolts down in You thread the bolts back out You torque the bolts down in Then back 180 out You torque the bolts to angle and the center a lil' more That's what it's all about!

Small update time.

I've driven the forester for the last week, it's no longer using coolant. Given that the oil weep from subie head gaskets can stay stable for a long time, it's looking like I'll leave well enough alone for now and revisit wether I need to take action in a few months time.

What a score, I purchased the car expecting a totally blown head gasket and have gotten out of it for a couple of hundred dollars in cooling system repairs.

Thanks to all who took the time to help out. I'll refer back here If I end up doing the head gasket later on.

Canoes deleted.

That was fast!

They were pushing a JDM engine supplier with poor online reviews. This ain't the first time they've spammed us either. Given the patterns, I doubt it's a robot doing it.

In case said company is reading: If you want to advertise on GRM, please contact them directly at https://grassrootsmotorsports.com/display-ads/ or https://grassrootsmotorsports.com/contact/. I promise, they won't bite.

All of this sneaky spamming by trying to ingratiate yourself into the community, then resurrecting zombie threads? It just puts you on our s#!+ list. And it makes you look as shady as your online reviews make you look.