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DIY 2001 Subaru Cylinder Head Gasket Replacement

143938 Views 116 Replies 27 Participants Last post by  greengoblin68
Hi everyone,
Yes, I'm new to posting on this forum, but trust me, I have poured over the threads and used this site on several occasions to fix my 2001 Subaru Outback, standard transmission, 2.5L SOHC 4 cylinder engine. Finally, at over 160K, my subie has developed the famous external head gasket leak. Yes, drivers side, rear. I have oil weeping from the seam, coolant in the back. Yes, I have strange odor. The coolant in my reservoir is still green but seems to be leaking more than the oil in my engine (which is not milky). I know what I need to do, the question is whether or not I can do it myself. I'm strongly inclined to try, but this would be the biggest automotive repair project I've ever tried. I've been studying these forums and reading and rereading my Haynes guide. My Haynes is going to be the step-by-step for my actions, specifically Chapter 2, Section 12 (Cylinder heads - removal and installation). Most of the instructions on this refer you to other manual sections, which I've spent the last two weekends just reading, looking and planning, and I think now is a good time to ask a couple of questions.

1) TDC vs. camshaft sprockets. Haynes instructs me to find Top Dead Center of the #1 cylinder by adjusting the camshaft pulley with a breaker bar while a compression gauge is in the sparkplug hole. I have a pretty good idea where this is already (the marks are still on the pulley from an earlier timing belt change), but I will run through the procedure anyways. I'm not really sure what to look for on the compression gauge though. Are there any play-by-plays out there for what to do exactly? Next I take off my drivebelts, then after a few other removals, Haynes recommends using a chain wrench to hold the pulley while loosening the crankshaft pulley bolt. I'm not sure about using a chain wrench here. Does anyone have any comments or alternatives? I feel like I'm going to have to wrench the heck out of the crankshaft pulley bolt. Correct me if I'm wrong, but if I get even ONE tick off of TDC I'm screwed here correct? Last question on this point, and I feel like I have a big knowledge gap here, but after removing the pulley and the covers and the timing belt guide, the next step is to "Turn the crankshaft and align the marks on the crankshaft sprocket, the left camshaft sprocket and the right camshaft sprocket with etc., " Won't this throw off my TDC? I'm hugely concerned about this, if you respond to nothing else, please advise on this.

2) Camshaft removal - after removing sprockets, valve covers, CMP, rocker arm assembly, tb tensioner/bracket, and dipstick Haynes says to remove the "camshaft end cap assembly" then "remove the camshaft carefully from the cylinder head so that the lobes do not nick the journal bores. Remove the camshaft oil seal and the end plug from the camshaft end cap assembly." Is this it? There are no diagrams, no photos. I'm just really vague on what to expect when I get in there, what it will look like.

3) Unforeseen difficulties - I'm planning on being methodical. In fact, I will be photographing EVERYTHING, labeling EVERYTHING with tags and I writing EVERYTHING down. When I'm done, it will be posted. Promise. I'm planning on having to buy some tools. Of course I'll need a torque wrench, spark plug remover, compressor gauge, chain wrench, and pin wrench. I have a wrench set, socket set, hammer (just kidding). I also plan on replacing the left/right valve cover gaskets, spark plugs and, of course, cylinder gaskets. I guess I'll need new cam seals too. I have some money for unforeseen expenses, I have a little time, a place to work. Is there anything else that I'll need that you can think of? Has anyone who has followed the Haynes (or Chilton. . .it's about the same) done this before and found out that something just wasn't covered properly? I want to get everything I need, then do this all at once. I want to keep this car running a while longer, I also want to learn about what is under my hood. Thanks for all your help.
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I was not planning on pulling the engine. I know it will be more difficult but I was told that it wasn't necessary for SOHC. Basically virtually everything will be removed from the engine compartment anyways.

I was planning on purchasing the manual but there are costs to that and I am in an exploratory stage.

I haven't selected head gaskets for sure. I was thinking about buying a SOHC full package from the

Do I really need to get the heads checked? I'm fixing the gaskets. I imagine checking the heads (and machine work) will add significantly to cost. But yes, there are machine shops available nearby. If this is a definite must do then I will do it.

Not brave, mainly just stupid. But I'm really interested to see if I can make this happen or not. It feels like if I just go through it step-by-step, take my time, be methodical, then I could get it done.
Thank you SO much to everyone who responded so quickly. . thank you especially for the FSM link! AWESOME! And some great advice too. I do have a couple of questions. I'll shoot them out quick. . .

1) If I don't need to find TDC to remove the timing belt, then it sounds like that issues is completely unimportant. How does this work though? I thought TDC was an essential component of almost all engine repairs. It seems so dodgy to just ignore it. "set the crank to the timing alignment mark before you remove the belt." What is the timing alignment mark? How do I make sure I have correct timing when I put the belt back on? (I won't be replacing the belt, it is only a couple thousand miles old)

2) Don't have to remove camshafts! Awesome. That seems to make my job ten million times easier.

I'm thinking seriously about getting an engine stand for this after all, maybe changing out my clutch while I'm at it. I'm kind of feeling like this job might be easier than I thought (still hard though). I'll have more questions later I'm sure. Thank you again for all your help.
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My Plan

Hi everyone! Thanks for all the fast responses and great links. I've poured over them and put together the following plan. If anyone has time I'd love to hear if there is anything you see that I am missing (or overdoing!) Thanks again for everyones help.

2001 Subaru Outback
2.5L, SOHC, 4 cylinders, standard transmission

Each step will be photographed before and after completion. All parts will be tagged and labeled. All bolts will be placed into labeled zip-lock bags. Each component will be stored in a separate box.

Procedure for replacing cylinder head gaskets
1. Check camshaft pulley bolt first. Either use “starter bump” method or impact wrench if the bolt is stuck.
2. Drive onto ramps.
3. Relieve fuel pressure by removing fuel pump fuse.
4. Remove washer fluid reservoir from engine compartment.
5. Remove battery from vehicle.
6. Drain coolant from radiator and from engine block. I might need to remove the radiator and fans for space, but I’m not sure yet. Inspect hoses while I am doing this. I might need a lower radiator hose and/or clamp.
7. Remove air intake components (housing, resonator and ducts).
8. Remove spark plugs.
9. Remove drive belts. Remove a/c tensioner adjuster and main drivebelt tensioner.
10. Remove timing belt covers. Remove crankshaft bolt completely. Remove crankshaft pulley. Remove timing belt guide. Turn crankshaft sprocket and align the marks on the crankshaft sprocket, the left camshaft sprocket and the right camshaft sprocket with the notches on the oil pump, the inner timing belt cover and the cylinder head seam. Clearly mark these areas and mark where the timing belt connects these areas. Mark the direction of the timing belt rotation. Remove idler pulley number 1 to release timing belt tension. Remove idler sprocket number 2 to make clearances for timing belt. Remove timing belt. After this point I can no longer adjust the crankshaft or camshaft sprockets or the valve heads may contact piston crowns. Remove crankshaft pulley sprocket from crankshaft. Remove bolt and timing belt tensioner. Without moving the camshaft sprockets from their alignments, remove sprocket bolts and sprockets and mark them as left and right. Remove inner timing belt covers.
11. Remove bolts from valve covers. Remove oil filler pipe on left side. Separate the covers from the cylinder heads. When replacing, replace valve gaskets
12. Remove camshaft position sensor.
13. Disconnect exhaust manifolds from underneath the cylinder heads.
14. Remove intake manifold. Detach spark plug wires from ignition coil on top. Clamp off and disconnect coolant hoses from throttle body (if I haven’t removed the radiator already). Disconnect fuel injectors, CKP, CMP, ECT, knock sensors, oxygen sensors. Remove power steering pump and position off to the side without disconnecting power steering fluid lines. Remove alternator. Remove a/c compressor and mounting bracket. Do not disconnect refrigerant lines. Disconnect PCV hose from intake manifold. Label and remove all vacuum hoses. Disconnect fuel delivery and return hoses from fuel rail. Remove the fuel rails from each cylinder head and keep injectors attached to the fuel rail. Disconnect accelerator cable and cruise control cable if equipped from the throttle body. Remove air assist injector solenoid valve and bracket. Disconnect and remove the air filter housing brace. Disconnect the vacuum hose, the vent hose and the purge hose from the evaporation pipe. Remove intake manifold mounting bolts and carefully lift the manifold off the engine with the throttle body attached.
15. Loosen cylinder head bolts in the reverse of the tightening sequence. Remove heads and old gaskets. Clean gasket mating surfaces of the cylinder heads and crankcase using a plastic scraper and light acetone or thinner. Have heads inspected by machinist at subarupair, inc. Replace both gaskets. Replace bolts. Carefully torque. Reverse order of operations.
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An update. Working on this repair this weekend. Canubarus first post has been invaluable so far. This website in general has been invaluable. Took all day for me to get to where I am at right now, (ready to remove sprockets). I found a couple of problems in my plan, but so far so good. I'm tgaking lots of pics. Ill put together a synopsis when I'm done. Thanks again for all the help!
I used the starter bump method. I broke my breaker bar on the first try because I gave the ignition too much "pop". On the second try I just barely feathered it (I was in neutral - standard transmission) and it worked like a charm.

Got the second cylinder head off last night. I gotta say that I just don't know how you would have the clearance to move that head around without removing the intake manifold. I know it's possible but I needed every inch I could get. I needed to lift the engine about two inches after loosening the engine mounts which were super rusted.

But both heads are off now. I'm going to get them looked at today. I already have a gasket set and hopefully if I don't need any resurfacing I can start putting them back on tonight. I don't know how I am going to get the torque I need for those cylinder head bolts. Clearance is so tight and those rockers are right there!!!
Sweet! Just got the heads looked at and they are perfect. Tonight I need to work on getting everything cleaned up nice and neat. I'll need to clean up underneath where the leak was (about a half inch of just crud), then of course the gasket interfaces, and maybe the pistons too. Probably run a cloth through my intake manifold pipes as well. Then I'll use jbwoods advice on torquing the bolts. The mechanic who checked the heads said it isn't as hard as getting the bolts out but cautioned that I make absolutely sure that I do it just the right way.

I am a little concerned about this. So if I torque the corners to 51 (I think), then it says to turn the bolts another 90 degrees, aren't I increasing the torque substantially? I don't get it. Why not just give me the right torque to set it at instead of giving me a "torque +90 degrees"?
Anyone able to clarify the bolt number locations? Haynes shows something I don't recognize. Standing at my tire looking at the bolts does it go 1 north, 2 south, 3 northwest, 4 southeast, 5 northeast, 6 southwest? Just double checking, hoping to get the darn things on tomorrow.
Got the heads back on (finally. . .I've been doing this while juggling a job and a kid). Tightened the bolts as directed and put the valve covers back on. It looks like the gasket is peeking through the head/block seam on top and below. I remember I could see the oem gasket at the top when I started, but not on the bottom. I used the FeldPro replacement gasket and its a little different, so I guess some variation should be expected. Does anyone view this as a glaring red flag, or has anyone oberved the same thing? I know I put them on right and I tightened the bolts perfectly. If that is okay, I'm going to get moving on putting the rest of the engine back together.
Should I replace the injector o-rings? I heard I should, but they look okay and they appear to require special ordering?
No. I meant injector o-rings. Since the injectors were removed when I removed the fuel rail and the intake manifold, I wonder if it's necessary to replace and reseat the injector o-rings since the pressure on the injectors was removed. They look okay. . .I was told I should replace them though or I risk an engine fire. Just double checking. . .apparently obtaining 01 subaru injector o-rings takes a special order. I won't do it if I don't have to.
I was surprised that I had to special order no matter which part store I talked to. Truthfully, the o-rings looked okay, no cracks or anything, and I haven't had any problems to date. It's just that when I removed the injectors I removed the pressure on the rings and I adjusted the seating, so I get a little nervous on the replacement. I guess I'll know I screwed up when my engine catches on fire.
Boy the timing belt is kicking my butt! I just can't figure out how to wrap that thing back around the cranks and pulleys. I'm trying to follow the Haynes manual instructions which instruct me to reinstall a reset tensioner, reinstall timing sprocket #2, then reinstall the timing belt. Except it just doesn't fit. I've seen some of the othe posts about locking down the right cam and guiding the belt on to the crank and the left cam using a socket wrench to turn the left cam by tightening the top and leaving the bottom loose to thread the idler sprocket 2 and idler pulley 1. Hopefully that will work. I'll give it a shot tonight. I don't know how I'm going to get the lining all matched up. I also thought about trying to get the crank and the left cam lined up (with the sprocket 2 and tensioner installed) then trying to "guide" or "thread" the belt onto the right cam by turning the crankshaft. That makes me a little nervous though.

A question. . .presumably I get the timing belt lined back up within a tick. Then I turn the crank 2, 4, 6 times. I presume the belt marks will end up slightly off the more I turn the crank, correct? I know the SPROCKET marks need to line up consistently, but does the belt? I'm assuming my belt marks are a guide to help me line things up the first time, but they won't line up forever.
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Yup, I gotta problem. Got the belt on, everything lined up, put the rest of the engine together, filled up on coolant and started it up. . .it started, for about 10-15 seconds until I shut it back down because of the shrieking noise and smoke/steam coming up. . .I guess I'm screwed. It was late, so today I'm going to loosen up the drive belts a little bit, change the oil and pull it off the ramps. . .then Ill start it up, give it some gas and see what happens. . .I'm not optimistic. . .but if figure I have nothing to lose at tbhis point. . .
UPDATE:! Actually, things are looking up. I loosened up the belts and that solved the screeching (way too tight) and then I let it idle for around 20-30 minutes and no more smoke. I'm getting ready for a test drive. Fingers crossed!
Test drive went well! I shifted through all gears, checked the AC, heater, cruise control. Things went well. Then I got home, pulled into the driveway and put it in neutral and the battery light popped on. Opened the hood, the alternator was spinning so I'm not sure what is wrong. Maybe the belt is TOO loose now? Or maybe a connection? Also noticed a little leakage on top of the power steering pump, not real bad though. But the important stuff, the gaskets, the smoke, the shrieking noise are not problems anymore. Gaskets look good everywhere, no leakage at all. So I shut it down and I'll tighten up the PSP clamp and check my connections again and then change the oil and tool around town this weekend before trying it out on the commute.

I'll also put together a post next week describing my process. I have around 150+ photos (HUGELY helpful when reassembling) and about ten pages of notes (also HUGELY helpful when reassembling). It took me about two weeks total, just a little short. Some long days on the weekends and nights after work. I did not need to pull the motor, I needed a little help at actually removing the heads but that's about it. Having the truck up on a set of ramps was important, you just need the clearance. After I break out the numbers I think I'll have saved about $600-1000+, acquired a set of nice Craftsman tools, and, most importantly, learned how my engine works. I can not emphasize enough that I AM NOT A MECHANIC. I didn't even do my own oil changes three months ago. If you take your time, be methodical, stay organized, study the manual, take photos, take notes, double check your work, follow directions and consult with others more knowledgeable than you (I called mechanics, parts shops and checked in with this forum regularly), you can do this work yourself. Many thanks to everyone who has offered timely advice, or has posted in the past, you were CRUCIAL to helping on this project. In the end, saving money, acquiring tools and knowledge (and did I mention I lost 7 pounds ?) are a great way to spend a couple of weeks. I hope others can learn from the dialogue that occurred here! Thanks!
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I actually had the belt cover OFF when I took it for a drive. Maybe that was the problem? I didn't hear any noise coming from the pump but the steering was a little jerky right when I turned the wheel the first time. After that no problems. I don't think the PSP is a big problem right now, I'm actually more worried about the alternator, but also, not a big problem given that yesterday I was worried about my MOTOR.
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