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2001 Forester S 4EAT
89 Posts
Discussion Starter · #1 · (Edited)
A thread for documenting planned and completed work for a 2001 Subaru Forester S automatic.

Purchased February 2020 as a project car and a fun snow/utility car when it's (eventually) running. Initial details:
145k miles
One owner
Good condition exterior and interior
Body rust on all wheels and rear differential
Needs head gaskets and power steering rack fixed
Sticky shifter when moving up and down 1-2-3

Some initial planned work:
Head gaskets and steering rack [steering rack turned out to be OK]
Flush all fluids
Fix sticky shifter

2001 Forester S 4EAT
89 Posts
Discussion Starter · #2 · (Edited)
Starting on the head gaskets. First thing removed: radiator, not too hard, plenty of rusty bolts and clamps to replace.

Next up was battery, washer fluid reservoir, and the intake. Unfortunately there's already a rust victim, one washer reservoir bolt head snapped off when trying to remove it :(. Everything else was straightforward.

After a brief hiatus (apparently we're supposed to be doing other things with our time too), we removed the belt covers, the belts, the alternator, the power steering pump (moved to the back of the engine), and the A/C compressor (left sitting where it mounts). We also removed the air intake bolts, so it can be slightly lifted off the heads. Thought about removing the intake completely, but we might get away with just taking off the manifold bolts - we'll see. We also tried removing the harmonic balancer but no luck, its on there tight. Going to rent the tool to get it off.

Well it took a lot of liquid wrench and a long torque bar, but we finally got the harmonic balancer off - it was really on there. The winning combination was using a floor jack handle to make a long torque bar, and jamming a tire iron in the torque converter (4EAT) to hold the pulley. Since we didn't take off the intake, we had to position the tire iron between the intake connection to the air box, and the throttle position sensor. Not the best idea. At least the timing belt looks like its been maintained regularly.

Ok, a big day - both cylinder heads are off. After removing the timing belt cover and timing belt, next was the exhaust manifold bolts under the engine and the valve cover bolts, all straightforward. We did the passenger side cylinder head first, it was very, very easy to get off with the engine in the car.

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1999 Forester 2.0 SLX Manual
73 Posts
Good luck! Does not look too bad.
We neither are susceptible to rust in Spain!
I used to live in the UK and cars didn’t last too long if used in winter. I hated working on my old junkers then.

2001 Forester S 4EAT
89 Posts
Discussion Starter · #7 · (Edited)
Continuing the head gasket repair. The driver side cylinder head was a huge pain, and much, much, much harder than the passenger side. You must take off the intake manifold, it is not worth it to try and get it off with the manifold sitting on top of the engine! Also, on the automatic (4EAT), there are two metal lines for the transmission bolted to the bottom of the cylinder head which also must be removed. We learned from our mistake and will be taking off the manifold to reinstall the cylinder head. By some luck, it came off. Another tip is to unbolt the driver side engine mount and slightly jack the engine up to gain some additional clearance. It is also critical to have a helper if possible! At the end of the day, its off (and we're exhausted).


Got the intake off - lots of connectors and hoses, went slowly and labelled everything. Big pain, but absolutely necessary. A bit of fuel spilled as well, since we didn't try to run the engine until it stalled before starting this whole repair, which is another handy tip. Next up is cleaning the engine block of the old gasket material.

Both cylinder heads are back on! Passenger side was once again very easy and overall the bolt sequence is straightforward with two people. Driver side was also much easier to install, after removing both the driver engine mount nut and the pitch mount at the top of the engine, and then jacking the engine up until the mount stud was almost clear of the cross member. The bolt sequence for the driver side was a little bit more painful, due to less overall space. Also had a few bolts creak between both sides, here's hoping its a good seal. Plenty of reassembly left to go, including new timing belt kit, new water pump and thermostat, and checking the valve clearances.


After putting the heads on, we found out that one of the seals of the coolant crossover pipe was leaking and badly corroded a bolt, so we replaced both the bolt and both seals. After that was a new water pump and thermostat, adjusting the valves, and installing new spark plugs. Timing belt was a little tricky, took a bit of time to get everything to line up. Rotated the engine a couple cycles and everything seems fine. Lots of cleaning in between as well, of the chassis, gasket surfaces, bolts, holes, etc.

Timing belt cover, crankshaft pulley, and air intake manifold were next to go on. For the pulley, we bought two 1/2" x 2" bolts and used a tire iron to brace the pulley while torquing the bolt - much easier than trying to brace the torque converter. Air intake manifold was much easier to install than remove, spent more time tracking down hoses and connectors. A major key was installing the power steering pump bracket and the A/C bracket and compressor before installing the manifold. There's really not much clearance to access bolts, so order of installation is critical. After that, in order: power steering pump, alternator, accessory belts and cover, radiator and hoses, the air intake box, and the battery. Another point: the Haynes manual lists 28 ft-lbs for the rear mount bolt of the power steering pump bracket - this is way too high! Use the same value as the front bolts (16 ft-lbs). We nearly destroyed the bolt in the block, luckily it came out when we realized something was wrong. Here's it all put together again:

Filled the engine with water from a hose and 5W-30 conventional oil, turned the key - and it fired right up! First issue was white smoke coming from the driver side head, turned out to be oil burning off the exhaust manifold. Then, water started leaking out steadily from the upper radiator hose connection on the engine block. Tightened all the radiator hose clamps and that fixed the issue. Drove the car about 6 miles and no signs of leaks - tomorrow we'll flush the water out and fill with Subaru coolant, and change the oil with a new filter.

So far so good! Learned a lot, it was our first major engine repair, and there's lots more minor maintenance ahead.

2001 Forester S 4EAT
89 Posts
Discussion Starter · #8 · (Edited)
The COVID shelter-in-place order in California has given us some additional time to take care of various small jobs:

  • drilled out a rusty bolt for the washer tank (after breaking an ez-out in it ... ), and put in a (smaller) bolt instead.
  • swapped the water and conventional oil for Subaru coolant and Mobil-1 synthetic oil. also changed the oil filter. hopefully this is a sufficient flush after the head gasket job.
  • fixed the clock, the failure was exactly the same as in this (very helpful) thread: ('98-'00) - 1999 - Oh no my clock doesn't work - how to fix it!
  • drained and filled the front diff, rear diff, and transmission. need to do another two flushes of the ATF to get close to a full fluid drain and fill.
  • replaced both upper radiator hose clamps, as it looked like coolant started leaking again from the upper hose connection to the engine block.
  • took off the front brake calipers and cleaned things up, like the caliper pins and related parts.
  • cleaned and greased the front door hinges to eliminate some annoying squeaking.
A nice layer of rust confronts us for nearly every small job, so its been slow going at times. Next up is cleaning up the rear brakes, inspecting and adjusting the parking brake, and bleeding the brakes.

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A month later, and we've installed a tow hitch and completed a pretty thorough brake service. The tow hitch turned out to be a bit of a hassle, as it required getting a few brackets off of the frame. On the rear passenger side, the carbon canister needed to be dropped, which ultimately required drilling out two rusty bolts ...

Fortunately, a quick trip to a local junkyard and we replaced the very rusty canister bracket. As for the brakes, we ended up replacing the rotors, the calipers, and the caliper brackets, and then bled the system. We also replaced the parking brake shoes and all of the parking brake hardware. As lots of trouble shooting some brake drag sounds, we're happy with the new parts, braking feels very responsive. Made more trips to junkyard and we also replaced the rusty (and unusable) caliper mounting brackets.

We also flushed the ATF again, one more time and we'll call it a full drain and fill.

The small jobs continue: the ATF has been drained and refilled three times, and the PCV valve and intake filter were replaced.

It looks like ATF likes to leak when filling from the dipstick tube, so we'll track down that issue at some point. There's also some oil at the back of the engine (on the front jack plate and the steering rack boot), but its not clear how big of an issue it is, or if its left over from the leaking head gaskets.

2001 Forester S 4EAT
89 Posts
Discussion Starter · #9 · (Edited)
Many "bugs" of this car have turned out to actually be "features" ... such as checking the oil and ATF levels. It looks like the only reliable way to check is after the engine/transmission are warmed up - the transmission in particular has a detailed approach for the hot level check. So we've been steadily adding ATF to try and get the level right.

After a weekend trip to Yosemite, it was time to address a somewhat persistent and alarming clanking/banging/thudding sound from the rear of the car. In particular, it likes to show up under load (e.g., accelerating up a hill). We figure its the rear stabilizer bar, given the condition of the bar itself and the reports on this forum of it being a common problem. We replaced the stabilizer links (OEM), link bolts (Ace Hardware), and the bar itself (junkyard). Of course, nothing is straightforward with a rusty car, and we had to deal with a snapped off weld nut in the driver side frame rail.

Another annoying handling problem while driving - the steering wheel vibrating viciously around the 60 - 70mph speed range. When we bought the car, the steering bellows were all torn up and we figured the tie rod ends needed to be replaced. Finally got around to it, and its already a huge difference in driving, almost no vibration whatsoever. Need to get the steering aligned next.
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We were planning for a while to replace the stock head unit with an aftermarket unit capable of running Android Auto, but we really didn't like how low the unit is in the dash. So, inspired by the second generation Forester option to have the head unit where the dash pod is, we decided to manufacture our own version for our SF.

We still have some finishing touches to apply on the side brackets, but overall its a great addition and we won't miss the dash pod storage area at all - we replaced the stock head unit location with two single DIN pockets, one of which has a USB cable for Android Auto.

In our quest to eliminate as much vibration, noise, and harshness as possible, we decided to replace the motor mounts. From watched the engine while starting the car, it was pretty clear they were too far worn. It wasn't easy to get to them, given the engine bay geometry and clearances, but with the help of a set of ratcheting and pivoting box wrenches, we were able to do it in a day. Here's what the old ones looked like, complete with oil and coolant stains from the previous head gasket leak:

We were also able to finally identify an alarming loud banging sound from the rear of the car, which shows up when accelerating uphill in the 45 - 55 mph speed range. After worrying it was a rear axle, strut, or bushing breaking down, it turns out the exhaust has way too much play in it and was hitting the spare tire area - likely due to the completely worn out exhaust cushions/hangers. After replacing three of them, the loud banging is completely gone - a huge relief!

The stock mudflaps on the SF are pretty much useless, and we planned to replace them at some point. Thanks to @F0RE2TER, we snagged a set of RokBlokz mud flaps and installed them. Pretty straightforward, aside from trying to clear out a mass of packed dirt behind both front mudflaps!

Better looking and much more useful than the stock set up.

2001 Forester S 4EAT
89 Posts
Discussion Starter · #11 · (Edited)
Ok, time to post some updates. We've gotten a lot more done on the car, some maintenance and some major upgrades.

The stock suspension on the SF generation is too soft, way too soft. The front passenger strut was leaking as well, so we decided to replace all of the struts. But which struts to use? No good options on rock auto, and way too expensive to buy a nice set of quick struts. After lots of searching, we decided to grab a full set of struts from an SG generation forester. According to other forum members, the SG struts are a straight drop in, are stiffer, and provided a nice little lift (~7/8"). Good enough for us, we even cheaped out further and got a full set from the junkyard! 7k miles on the struts, and they are a great upgrade with no issues. Here's what the stock struts looked like after ~150k miles:

Finally got around to fixing another painful issue: leaking front driver CV axle. On top of that, we were pretty sure that the front axles were responsible for a very annoying floor pan vibration at highway speeds (~65 mph). A tip for this repair: just take the strut bolts out (which connect the strut to the hub assembly). You might need an alignment afterwards, but we found it to be the simplest option for getting the axles out - by far. No real troubles with this one, besides struggling to knock out and reinsert the roll pins at the front differential. Dropping the exhaust off the heads really helps here. The front passenger axle had too much slop in one of the cups, likely causing the vibration. We ended up getting a pair of NAPA axles since the OEM price is very steep. No issues after ~7k miles!

2001 Forester S 4EAT
89 Posts
Discussion Starter · #12 · (Edited)
Major upgrade time.

May 2021 - July 2021
After upgrading the suspension and replacing the front axles, we enjoyed driving the forester and taking it on long road trips to the Sierras. Of course, the lack of power from the EJ251 was very noticeable starting at 3000 ft. The SF forester is a fun little platform, but dragging it up and down the mountain was starting to get a little annoying. Keeping up with traffic required running it at 4k-5k RPM, which just didn't seem fair to the poor EJ251.

So we decided to engine swap Rusty. After looking around other SF projects and mods, we came across a couple engine swaps which replaced the stock 2.5 EJ251 with a 3.0L EZ30D from a 2000-2004 outback LL Bean edition. Given the relative "simplicity" of these swaps, we decided to go for it.

In December 2020, we got a great deal on a 2001 Outback LL Bean with ~145k miles.
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We delayed the project a bit at this point, as we were busy with other things. In January 2021, we compression tested the 3.0 engine to make sure it was in decent condition, and replaced the spark plugs while we were in there. In March 2021, we started working on the Outback to pull the engine out. Part of the purpose of this project was to do even more complicated things we'd never done before on a car, like pulling out an engine.

With the 3.0 engine out and on a stand, we started on a few maintenance items it required: resealing the front timing chain cover, oil pan, and cam covers; replacing the thermostat and oil cooler seal; and replacing the engine mounts, rear main seal, and wrist pin o-ring. A few more things were replaced once the engine was in the car: power steering o-rings; intake and exhaust manifold gaskets; EGR gasket; old and destroyed rubber vacuum hoses; and idler pulleys.

Of course we had to get the 2.5 engine out as well, once we pulled the 3.0 engine it was time to swap the cars and start working on the forester. Thanks to our previous head gasket repair, we were very familiar with tearing down the engine, and we made short work of pulling out the engine.

Continued in the next post ...

2001 Forester S 4EAT
89 Posts
Discussion Starter · #13 · (Edited)
May 2021 - July 2021
The mechanical aspect of this project turned out to be mostly straightforward - the EZ30D drops right into the front subframe of the forester. Since the 3.0 engine crank pulley has 5 grooves compared to the 2.5's 4, we used all of the engine accessories from the 3.0.
  • The power steering pump, reservoir, and hoses from the outback connected directly at the rack
  • We used the low pressure A/C hose from the outback due to the geometry of the intake manifold, and retained the rest of the forester A/C system
  • The radiator fans would have to be aftermarket, as there was no space between the engine and the radiator for the stock fans
It was very exciting to the see the new engine in the car!


What turned out to be more challenging (and frustrating) was wiring in the outback ECU. Taking apart the dashboard completely wasn't too bad, but we were reluctant to disassemble the metal bar and all of the wiring behind it, with the fear that it would never quite go back together correctly again. We compromised and took apart just enough to get the heater core out, which gave us full access to the front wiring harness. Below on the left is the outback front dash harness lying on our garage floor, and on the right is our attempt at organizing the forester harness in the car.
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We actually ended up wiring the ECU twice! The first time, we didn't test as we made connections and we ended up with a nasty issue where a fuse would blow trying to turn the ignition on. After we got stuck trying to debug and fix the issue, we committed to undoing everything and rewiring it, testing every 5 or so connections and verifying what we could with a multimeter. Fortunately, we were successful in reading the ECU and turning the ignition on the second time, so next up was trying to idle the car for a minute with the bare minimum setup: intake manifold and engine accessories, but no cooling system. Without the radiator, we also had to bridge the transmission cooler lines to avoid pumping ATF all over the floor.

From the test start, we realized the outback exhaust system actually collided with the spin-on external filter of the transmission. It turns out subsequent generations of the forester eliminated this filter, and moved it internally - just our luck. To avoid damaging the filter, we fabricated exhaust spacers to offset the exhaust system, which we installed at the heads, and resolved the issue. Next was finishing up the cooling system by installing a pair of aftermarket fans. Here's what we came up with:

We also had to cut one of the transmission cooler fittings to make room for the rubber hose to fit in front of the engine, as well as fabricate an adapter plate to use the forester radiator mounts with the outback radiator. With the cooling system finished, we ran the car at idle to make sure the ECU was happy and the fans would kick in. After 45 minutes, we called it a success! At this point, we were working to finalize everything: soldering all of the ECU wiring (which also involved adding conduits to route wiring from the ECU to the alternator and A/C compressor) and reassembling the rest of the engine bay. A few more things came up as we reassembled things:
  • A tach converter was necessary to fix the engine speed output from the ECU to make the TCU and cluster happy, since we didn't swap the cluster
  • The exhaust (cat-back) had to be recut partially to make it fit underneath the forester
  • The coolant bottle needed a home, and there wasn't much space in the engine bay!

Here's some IR camera pictures for fun:

So far the swap is a ton of fun to drive, the forester is much quieter and smoother than before and the increased power is noticeable. We figure we got an additional 50 hp and 50 ft/lbs out of the swap, which has been a blast to take up and down some steep hills. 500 miles on the swap, and so far no issues.

2001 Forester S 4EAT
89 Posts
Discussion Starter · #16 · (Edited)
August 2021 - September 2021
A few final details on the engine swap.

We waited a month before charging the A/C, to make sure everything else was working without any engine codes, and because we weren't sure what signals the ECU needed. Part of the issue was that the 2000 - 2004 H6 Outbacks have an A/C compressor with 3 wires, while the 2001 Forester only has 1 wire (for the magnetic clutch). After a lot of searching, it turns out the additional 2 wires for the H6 Outback is a revolution sensor, to tell the ECU that the compressor is spinning and not seized when the magnetic clutch engages (source). We had to run two additional wires from the engine bay to the ECU for this sensor, but that's all it took to get the A/C working once we charged it.

The cooling system turned out to be the biggest pain after the swap, as the EZ30D generates a ton of heat and we didn't have as effective of a radiator/fan setup due to the lack of space between the engine and the radiator. First, we welded a sturdier coolant bottle holder, since the plastic bottle kit came with very flimsy brackets.
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Next, we found that under high load conditions with high ambient temperatures (100F+), the engine temperature would not drop below 200F, sometimes not even dropping below 210F. This wasn't too surprising, given how cramped the engine bay now was, the reduced cooling capacity of our custom radiator setup, and the poor airflow out of the engine bay. We decided the best answer to all of these problems would be ... hood vents. We bought a pair of hood vents from subiworks (the only SF hood vents we could find) and even found a 2001 Forester at a junkyard to get a spare hood (the same color!). A few hours with an angle grinder and a drill got the job done.
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The hood vents completely solved our overheating issues, confirmed by a few trips to the Sierras. Well, it wasn't completely the hood vents, it turns out the 20A fan fuses were blowing as well! SPAL actually recommended 25A fuses for the low-profile fans we chose, and we decided to simply swap in the 30A fan fuses used in the 2001 Outback H6. We also replaced the radiator cap, to make sure there were no pressure issues with the cooling system.

With the cooling improvements, we haven't had any more issues with the swap.

388 Posts
Congrats on your perseverance in accomplishing such an engine swap!
I've done similar in the past and can honestly say that while I was pleased with results, I would not do it, again. So, I know how you feel when you say, ".. just buy a faster car!"
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