Hey all! 04 WRX got me wrenching above my weight class.

LeafMeAlone · 05-18-2025, 07:28 PM

Hey! I bought a 2004 WRX 2.0L back in January, and despite it being a bit leaky, it's a wonderful car to drive. I've never done much of my own maintenance, but a 20 year old car with tons of available parts won out against buying from a dealership, so I've been getting my hands dirty the past couple months.

Sadly, I do think it's time to replace the head gasket. I have already done some other work to the vehicle (replaced the right side valve cover gasket, as well as swapping some interior stuff, and am replacing front struts and an axle in a couple of weeks. I still have to do the right side VC gasket, but due to a snapped bolt on the right, I am planning on redoing the fix I've already done. Between removing the struts, and the right CV Axel in a couple weeks when I have time, I realized it's probably better for me to just go in and replace everything I can, to avoid any other surprises in the future.

So, to get to the point of this post; I already have done a bunch of research, and have most of the kind of tools I'd need (thanks to this forum answering most of my questions years before I even have them, y'all rock) as well as the Hayes manual for the car, which has been helpful.

What I'm curious is, I have a decent budget, and plan on doing everything I can to avoid problems, but since I'm not experienced, would anyone be willing to offer other things I can replace/update for when I have half the engine open? My plan is already to do the following, so if you think of anything else that might be helpful, or save me some headaches, I'd appreciate it.

Valve cover gaskets (Both sides)
Head gasket (bought new head bolts as well)
Water pump/belt

Ill also have replacement gaskets for the exhaust and intake manifold, which I'll probably do as well if it makes sense.

Would it be smart to grab new hoses as well? Most are old, but functional, but I don't wanna have to go back if something happens, yaknow? So, If so, what are the hoses I should search for?

I'm getting the water pump and head gasket kits, to try and avoid having to ride a bicycle to an auto store, but if you are knowledgeable, please let me know if there's anything else that's super easy to do while down there.

Thanks for the time, I am indebted to this forum, and appreciate all of you!

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Unabomber · 05-19-2025, 08:30 AM

https://forums.nasioc.com/forums/sho....php?t=2740715

There is no water pump belt, that's the timing belt and its a larger job.

You do not need/want to replace the head gaskets unless you are 100% sure they are leaking. That's a whole motor out job and requires decking the heads which is not a DIY thing.

All hoses should be checked and replaced. You need a new OEM MAF and BCS and likely an aftermarket turbo inlet.

Jack · 05-19-2025, 08:36 PM

As Ron asks, you probably want to bring the car to a good mechanic very familiar with Subarus to prove that either the head gasket is bad or that it's not. This is NOT a newbie friendly thing to repair and with a car this old is often a reason people junk the car.

LeafMeAlone · 05-19-2025, 10:28 PM

I appreciate the input. The head gasket is definitely at the end of its lifespan regardless, it's got 140k miles on the original gasket, and when it drives hard, you can tell there's a leak. There's smoke on the passenger side from a drip onto the exhaust, so if anything I'll try and look closer to see if it's just a hose or the whole gasket that's causing it. Thankfully I have a couple knowledgeable people that I can call on if I get too deep, but I'll definitely keep that in mind before I commit to pulling the head. Thanks for the responses!

cmiovino · 05-19-2025, 10:58 PM

Fellow 2004 WRX owner here.

Usually speaking, the headgasket isn't a problem on these EJ205's. Yeah, they can go with extreme modifications, but usually speaking they're rather robust.

I've had my car 12-13 years now and I've been wrenching specifically on Subarus for near 20. I wouldn't date do a headgasket job myself yet. A buddy and I resealed and did the HGs on a Baja turbo a few years back. Full engine out job, heads off to a machine shop, setting timing correctly, remembering all the bolts, etc. He's a mechanical engineer and has many years experience working on personal cars and flipping others. I helped.

You really need to know what you're doing though. Sealing it all correctly, torquing in the correct order and specs, being decently clean.

Clutch replacements, headgaskets, and timing belts are on my list of "give it to the shop" time. It's just easier when they have a lift, engine hoist, and if it's a Subaru shop they know all the little ins and outs.

MyWRXbreaks390 · 05-21-2025, 04:38 PM

I made an attempt on this in my 08 wrx. Its very hard to do without a lift and knowing your way around the car. Absurdly enough it was cheaper for me to buy a new engine and just dump it in than do the gaskets and valves. Took way less time as well. I know that is the case for the EJ255 I don't know all that much about the cost out the box of the 2.0.

mconnell · 05-21-2025, 05:22 PM

If you are getting a bunch of white smoke yeah it is probably head gaskets but it really is SOO much work to do them. I am having oil smoke issues and im not really sure if its just blowby or if its turbo seal, but if you can take off your inlet and check for oil you might be able to narrow it down, and turbo seal isnt too bad, you can send the turbo out to get rebuilt for like 300$. I get want to take care of it while your in there but head gaskets would mean dropping the motor and you shouldn't exactly have to do that for struts lol.

Ernest · 06-08-2025, 06:14 PM

Bring it in. Smoke of the passenger side is typical of valve cover leak. Oil drips on the uppipe which runs real close to it. I have had the passenger valve cover changed twice in 22 years and 163k miles. Headgasket is still fine. Stage 2 tune since about 40k. But mine is a 4eat so it’s not beat on, but driven briskly. Good luck.

05-18-2025, 07:28 PM	#1
LeafMeAlone Scooby Newbie Member#: 540938 Join Date: Apr 2025	Hey all! 04 WRX got me wrenching above my weight class. Hey! I bought a 2004 WRX 2.0L back in January, and despite it being a bit leaky, it's a wonderful car to drive. I've never done much of my own maintenance, but a 20 year old car with tons of available parts won out against buying from a dealership, so I've been getting my hands dirty the past couple months. Sadly, I do think it's time to replace the head gasket. I have already done some other work to the vehicle (replaced the right side valve cover gasket, as well as swapping some interior stuff, and am replacing front struts and an axle in a couple of weeks. I still have to do the right side VC gasket, but due to a snapped bolt on the right, I am planning on redoing the fix I've already done. Between removing the struts, and the right CV Axel in a couple weeks when I have time, I realized it's probably better for me to just go in and replace everything I can, to avoid any other surprises in the future. So, to get to the point of this post; I already have done a bunch of research, and have most of the kind of tools I'd need (thanks to this forum answering most of my questions years before I even have them, y'all rock) as well as the Hayes manual for the car, which has been helpful. What I'm curious is, I have a decent budget, and plan on doing everything I can to avoid problems, but since I'm not experienced, would anyone be willing to offer other things I can replace/update for when I have half the engine open? My plan is already to do the following, so if you think of anything else that might be helpful, or save me some headaches, I'd appreciate it. Valve cover gaskets (Both sides) Head gasket (bought new head bolts as well) Water pump/belt Ill also have replacement gaskets for the exhaust and intake manifold, which I'll probably do as well if it makes sense. Would it be smart to grab new hoses as well? Most are old, but functional, but I don't wanna have to go back if something happens, yaknow? So, If so, what are the hoses I should search for? I'm getting the water pump and head gasket kits, to try and avoid having to ride a bicycle to an auto store, but if you are knowledgeable, please let me know if there's anything else that's super easy to do while down there. Thanks for the time, I am indebted to this forum, and appreciate all of you! * Registered users of the site do not see these ads.

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05-19-2025, 08:30 AM	#2
Unabomber Big Ron Super Moderator Member#: 18062 Join Date: Apr 2002 Chapter/Region: MWSOC Location: Muncie, IN Vehicle: 2004 WRX Sport Wagon Platinum Silver Metallic	https://forums.nasioc.com/forums/sho....php?t=2740715 There is no water pump belt, that's the timing belt and its a larger job. You do not need/want to replace the head gaskets unless you are 100% sure they are leaking. That's a whole motor out job and requires decking the heads which is not a DIY thing. All hoses should be checked and replaced. You need a new OEM MAF and BCS and likely an aftermarket turbo inlet.

05-19-2025, 08:36 PM	#3
Jack Add Lightness Moderator Member#: 13699 Join Date: Dec 2001 Chapter/Region: NESIC Location: Hopkinton, MA Vehicle: 2021 Building It Better	As Ron asks, you probably want to bring the car to a good mechanic very familiar with Subarus to prove that either the head gasket is bad or that it's not. This is NOT a newbie friendly thing to repair and with a car this old is often a reason people junk the car.

05-19-2025, 10:28 PM	#4
LeafMeAlone Scooby Newbie Member#: 540938 Join Date: Apr 2025	I appreciate the input. The head gasket is definitely at the end of its lifespan regardless, it's got 140k miles on the original gasket, and when it drives hard, you can tell there's a leak. There's smoke on the passenger side from a drip onto the exhaust, so if anything I'll try and look closer to see if it's just a hose or the whole gasket that's causing it. Thankfully I have a couple knowledgeable people that I can call on if I get too deep, but I'll definitely keep that in mind before I commit to pulling the head. Thanks for the responses!

05-19-2025, 10:58 PM	#5
cmiovino Scooby Guru Member#: 134005 Join Date: Dec 2006 Chapter/Region: MAIC Location: Pittsburgh, PA Vehicle: 2004 WRX Premium PSM	Fellow 2004 WRX owner here. Usually speaking, the headgasket isn't a problem on these EJ205's. Yeah, they can go with extreme modifications, but usually speaking they're rather robust. I've had my car 12-13 years now and I've been wrenching specifically on Subarus for near 20. I wouldn't date do a headgasket job myself yet. A buddy and I resealed and did the HGs on a Baja turbo a few years back. Full engine out job, heads off to a machine shop, setting timing correctly, remembering all the bolts, etc. He's a mechanical engineer and has many years experience working on personal cars and flipping others. I helped. You really need to know what you're doing though. Sealing it all correctly, torquing in the correct order and specs, being decently clean. Clutch replacements, headgaskets, and timing belts are on my list of "give it to the shop" time. It's just easier when they have a lift, engine hoist, and if it's a Subaru shop they know all the little ins and outs.

05-21-2025, 04:38 PM	#6
MyWRXbreaks390 Scooby Newbie Member#: 540101 Join Date: Jan 2025 Location: Latitude: -48.8767 Longitude: Vehicle: 2008 Impreza Wrx Paint is cooked	I made an attempt on this in my 08 wrx. Its very hard to do without a lift and knowing your way around the car. Absurdly enough it was cheaper for me to buy a new engine and just dump it in than do the gaskets and valves. Took way less time as well. I know that is the case for the EJ255 I don't know all that much about the cost out the box of the 2.0.

05-21-2025, 05:22 PM	#7
mconnell Scooby Newbie Member#: 541113 Join Date: May 2025	If you are getting a bunch of white smoke yeah it is probably head gaskets but it really is SOO much work to do them. I am having oil smoke issues and im not really sure if its just blowby or if its turbo seal, but if you can take off your inlet and check for oil you might be able to narrow it down, and turbo seal isnt too bad, you can send the turbo out to get rebuilt for like 300$. I get want to take care of it while your in there but head gaskets would mean dropping the motor and you shouldn't exactly have to do that for struts lol.

06-08-2025, 06:14 PM	#8
Ernest Scooby Specialist Member#: 45076 Join Date: Oct 2003 Chapter/Region: Tri-State Location: Rockland County, NY Vehicle: 2004 Stg 2 wagon AT 16 BRZ. Both silver	Bring it in. Smoke of the passenger side is typical of valve cover leak. Oil drips on the uppipe which runs real close to it. I have had the passenger valve cover changed twice in 22 years and 163k miles. Headgasket is still fine. Stage 2 tune since about 40k. But mine is a 4eat so it’s not beat on, but driven briskly. Good luck.