Subaru 2.5 L engine - the worst engine ever?

This thread belongs in the Rant-N-Rave section (if they still have it), not here in the area for actual car questions.

Subarus were having head gasket problems 30 years ago and then as now, Subaru denied there was ever a problem. Subaru even had a service bulletin issued way back when stating there was not a problem with their head gaskets (marketing dept. at work) but would cover them “if the customer squawked enough”. Not phrased like that but you get the point.

JMHO here, but I feel the problem is a bit deeper than head gasket design. They’re using 6 head bolts per side as compared to the earlier (and generally trouble free) 8 bolt design.
Another factor is lack or a head bolt retorque at a very low mileage. In theory torque to yield bolts should not be retorqued. In practice it may be a different matter since every metal known to man changes its shape over time.

I will add a good source of info on headgaskets in non turbo 2.5L subaru is here-> http://allwheeldriveauto.com/subaru-head-gasket-problems-explained/

Been a year since the last post on this thread. But the problem is still with us.

In the past 10 days three Subaru’s, 2001, 2002, 2003 that I had checked out by my mechanic on a pre-purchase inspection had the beginnings of head gasket leaks. As in my mechanic’s experience, all were on the left front of the engine. Mileage ranged from 91-115,000. Two Forester’s and a Legacy.

I have heard all the excuses, that other cars have head gasket failures, if we get to 100k miles what are we complaining about. All bosh. I have owned a lot of cars in my life. Take them to high mileage unless they get totaled, as my Prelude did at 190k. My first, a '62 Ford Falcon went to 219k. None of my cars ever had a head gasket failure, except my 1997 Outback where the head gasket failed around 120,000 miles. The prevalence of this problem is undeniable on Subaru’s of this vintage. It is shameful that the company let this go on for so long.

Just FWIW, the 3.8L is no longer made, and hasn’t been for years. But it was a lemon, arguably significantly worse than the Subaru.

And the widespread Taurus/Sable/Windstar transmission problems have been gone for 15 years…

I stumbled across your post after experiencing the same hg failure you describe. We own a 2001 Subaru Outback with the 2.5L engine and at 99,988 miles our hg failed. Keep in mind this is a 9 year old car that has been driven a little over 10,000 miles a year since it was bought. The conditioner was added to our car, but alas, the conditioner is not a problem solver/fixer. The hg was poorly designed. Instead of SOA owning their mistake in design (which I’m sure they decided to option to do the right thing for customers would cost too much since you have to remove the engine to replace head gaskets), they slap a band aid on the issue.

I will never buy nor recommend a Subaru to anyone. It is inexcusable to make a $30,000 car that require major engine repair before 150,000 miles. To not value the customer experience is even more revealing of Subaru’s company culture. I’m going back to Honda as soon as I get my 5 ton station wagon out of the shop. I refuse to drive a time bomb any longer.

I had a head gasket fail on my 1966 Impala. I forgave it; it was over 30 years old. What I want in particular is a car that costs more than my Honda to be as reliable if not more so. Otherwise, what am I paying for? Or what would even be better is a company that stands behind what they make by solving the problem, not duct taping a solution to buy time.

And be honest, a head gasket failing before 150,00 miles is rare for any car made 2000 on…unless of course you own a Subaru.

Yes, it’s a poor design. Yes, it’s disappointing to have that type of failure at such seemingly low miles. However, once the repair has been done the first time (assuming the use of high quality aftermarket (felpro MLS type are excellent) gaskets and quality workmanship from your mechanic), this will never be an issue again. And aside from that particular issue, they have very few common problems and will regularly last 300,000 to 400,000 miles or more. I own a 2000 outback with 277,000. We have a customer with an '01 outback with 425,000. It’s engine is just now getting tired. Very good cars if taken care of.

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Thanks , you just dragged up a 6 year old thread that has spam on it.

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There was a thread here a while ago which suggested the subie head gasket quality isn’t the actual problem, but just that the head gasket in that engine design has a more challenging job to fulfill than other engine designs. B/c of the tight tolerances involved, resulting from an engine design objective to provide improved coolant flow through the engine. In other words bigger coolant passanges means less distance at the head/block interface from those passages to the combustion chambers, etc.

when I owned Subies, I bookmarked this article:
https://allwheeldriveauto.com/subaru-head-gasket-problems-explained/
https://allwheeldriveauto.com/subaru-head-gaskets-problems-explained-part-ii/

essentially: if owner neglects his car, this opposite-engine design will give up on these gaskets due to increased coolant acidity eating material away in this high-flow/high-pressure design and/or if grounding is not sufficient

it is indeed a predisposition for this kind of failure, as their 2.2 liter engine never had such issues, so in newer 2.5 they changed the way how channels with coolant go around and now it is way more material separating cylinder form coolant, at least at a point where head contacts the block, so headgasket topic is closed for good

I have my own opinions about why the head gaskets fail. If it was block design then this should mean that any head gasket replacement is futile.

I’ve done a lot of Subaru head gasket replacements and never had a single one come back.

Subaru EJ engines have numerous ongoing issues that Subaru refuses to address; head gasket failures, “ring land” failures, rod bearing failures, high oil consumption, etc. Any of these issues can, and often do lead to catastrophic engine failure.

So exactly what is the story behind this “ring land” failure?

ok4450 - Weak cast pistons, bad factory tune, engine knock among other things.

I can’t say that I’ve ever seen a case of ring land failure on a Subaru and the few that I’ve seen with a rod bearing knock usually had a history of few oil changes and/or running the engine low on oil.

If by engine knock you mean pre-ignition rattles that will definitely cause a piston problem. In most cases that’s caused by too low octane fuel (especially on turbocharged…) or by an EGR system fault.
That’s hardly a design flaw.

Are you a Subaru tech? These engines are infamous for all of the issues I cited.

I’ve been accused of it and I’ve owned 3 Subarus in the past.

I’m just saying that I’ve never seen these particular problems. From what I glean from an internet search the common threads seem to be turbocharging, hard driving, altering the state of tune, and even oil in the combustion chambers.
I might point out that oil in the combustion chambers essentially lowers the octane of the fuel/air charge and which can then affect pinging.

Offhand, it sounds to me like the ones with the problems are being flogged. That wouldn’r surprise me as I’ve seen 3 near new turbo Subarus being hammered for hours at the local drag strip.
Two of them still had the dealer paper plates on them and I can just imagine the conversation at the dealer the following week when there are issues…

I don’t deny that the issue is typically associated with turbocharged cars driven hard. Then again, something about Subaru’s’ marketing of the WRX suggests hard driving is OK.

What they don’t mention is that these engines burn oil, run hot, have several points of lubrication failure, have no low oil pressure indicator, etc.

Hard driving increases the rate of wear in a typical car. In a Subaru, it leads to expensive, catastrophic failure.

Imagine dropping a medium-sized payload into your late model pickup and having the bed fall off.

The marketing departsments of ALL car manufacturers suggest a lot of things. Most are not true.

Some ads show 10 tons of rock being dropped from up high into the bed of a truck with no harm done either.