1999 Subaru Forster Engine Swap

My 1999 Forester has finally blown it’s EJ25 engine. Looking to put in a replacement (with the help of a friend who’s done it before) and was told a foreign import EJ20 would be a good option. Anybody have any experience with this type of swap? Will it be underpowered with the smaller engine? Will it “plug and play” or will we have to do modifications to make the different size fit? I’m over my head when I look at the Subaru chat rooms for information.

Just my 2 cents, but you would be far better off to install what the car is coded for. Doing otherwise opens up a can of worms in most cases.
In many instances even installing the same size/type engine from an adjacent year, much less a different type, may mean a lot of jury rigging.

I’ve done a lot of Subaru engine work and swaps but not the particular one you’re referring to. There’s no way I would consider doing this. If it’s a DIY deal where money and time is not an object then it may be feasible but the odds are that this is something you will come to regret after spending way more money and develop too many headaches adapting something compared to just installing the correct engine to begin with.

@DeniseB … if you live in a state that requires emissions testing, be sure to contact them first, before installing a replacement engine that is anything other than an exact replacement. You may not be able to register your car otherwise.

Few of these swaps will 'Plug & Play…" The first thing you are likely to discover, the plugs are different! It’s all downhill from there…If you are not subject to emissions testing, you can workaround most problems, but if that CEL refuses to function properly, it can be a real nightmare.

Yeah, I agree with the above comments. Definitely get an EJ2.5 engine. You don’t want to run a Forester with a smaller engine. It will bolt on but it will be way underpowered. EJ20 engines do not have the dreaded headgasket issue as the EJ25 engines do, tho.

I’ve done several Subaru swaps. It isn’t particularly very difficult, even for a DIY job if you’re halfway handy with wrenches. You can buy an engine hoist from Harbor Freight that will easily do the job.

If you’re getting a JDM engine, beware that, if they are right off the boat, it will not come with an EGR valve. JDM engines are the Japanese low mileage engines - great deals but they are not complete for US markets. Often times they are not rebuilt engines; just engines with maybe 40K on them. Good deal, tho. REgarding the EGR, usually you have to knock a plug out and install one. There are several engine builders out there that will provide a turn key solution based on JDM engines with EGR, a new timing belt and head gaskets installed. Those engines are practically new. A bit more but probably worth it.
Also check into getting one directly from a subaru dealer. Last I heard, they were selling certified rebuilt long blocks for a price competitive to a JDM low mileage engine. I found this out after the fact.

Agree with the others, you’re asking for headaches trying to install something different. All the electronics key to the engine and sensors. Not worth fighting that battle, to me.

Wow, thanks for the fast responses! A little more info… I’m in Washington State so emissions isn’t a problem. The friend that’s helping already has all the tools and engine hoist and has done a swap on an older Justy. Cost is a big factor for me, time isn’t an issue. Debated whether or not to salvage this car after 200K+ miles and 3 head gaskets or put the money towards another vehicle. But it’s a nice S model and will be primarily used for commuting by my college-aged daughters. Salvaged 2.5 engine with 85K miles is $2000 versus japanese 2.0 with 50K for $900. Are these prices reasonable?

Doing a Justy is way different, that was a much older/simpler (electronics-wise) vehicle. Has he done this exact swap? If not, I’d be very cautious about this.

Two grand for a used engine which may be a roll of the dice at best is a bit much on a 200k miles plus Subaru.
Even using a JDM engine of the same type could turn into a crap shoot as it may not be EGR equipped or who knows what else it’s lacking. Lack of an EGR could lead to engine rattling (and eventual destruction), CEL illuminated and no way to get rid of it, etc, etc.

IF the car is straight, and IF the transmission is good then it may be worth fixing IF you can find a reasonably priced (not 2 grand) motor that is known to be good.
There’s a lot of ifs involved.

You might dig around on eBay or Craigslist in your area. If you go with a used engine odds are you can find the exact match for a lot less than 2 grand and any used engine should get a new timing belt kit before installation unless it can be proven in writing that it was already done in recent memory.

You also might check www.car-parts.com.

Ah yes, that’s my dilemma. How much do I want to bet on a bunch of “ifs”… Car is straight, exterior is clean and we replaced the transmission already. But it’s still an older car. Guess I’ll keep looking for that sweet 2.5 engine that’s sitting in some garage, just waiting for me to find it. Thanks for all the help.

@DeniseB … I think you need to cosult w/someone who has actually done a 20 for 25 swap before going down this road. It doesn’t look like anyone here has. Maybe check out the internet Subaru forums? I wouldn’t advise this unless you have someone who you can consult with that has done it successfully (here in America, preferably in your state) before. Also, even if your state doesn’t have emissions testing, I believe Federal law requires your car to have all of its original emissions equipment installed. If anything is discovered missing after the swap, you risk a potentially expensive fine.

I’m not saying give up. The savings seems pretty significant. And a 20 for 25 swap may still be perfectly do-able,producing good results. My advice is consistent w/the other expert comments here, just don’t go down this road by yourself.

Thanks, we’re on the same page and I haven’t decided which way to jump yet. I’m asking more questions on some Soob sites to see what may or may not work in regards to the 2.0, but also looking for a deal on a 2.5 if one turns up.


If a 2.5 “turns up” you should put it on an engine stand and do these things before installing it

Timing belt
All idler pulleys
Tensioner pulleys
Front and rear crank seals
Cam seals
Water pump
Valve lash adjustment
Wires if applicable

Many of these things will be MUCH easier to do with the engine out of the car