Which engine models blow head gaskets?

[sonyhome]

I'm shopping for a Forester or Outback BTW around '00~02 so this is what the forum infos provided me so far. Take it with a grain of salt, the info may not be 100% exact, so do post corrections if you can.

 

General HG rule of thumb

 

All EJ25 2.5L 4cyl. engines up to 2002 have a higher incidence of gasket failures than normal:

DOHC, aka Phase 1 have the worst symptoms with blown gaskets (internal leaks). These engines have 2 humps for the camshafts on the black valve cover on the front of the engine near the radiator. Air filter is on passenger side with tube going through the fender wall. That should be Forester '98~'00 and Legacy/outback '96~'01 (?).

SOHC, aka Phase 2 develop external coolant leaks. They have one hump, and appeared around 2000. Air filter is at top rear of the engine behind the throttle body with the tube going above headlight on top of the radiator. Tha should be Forester '01~'02 and Outback '02 (?).

 

'03 and beyond, the gasket failure seems to be fixed. Maybe...

 

The gasket failures tend to happen more frequently around 100k~140k miles, but some have been reported at 60K... Past 140K some board members would consider it normal wear and tear for any engine to develop a HG leak, especially if an incident causes the engine to overheat. Most HGs can be trouble free for over 200K. The consensus in the forum is at most 15% of the engines experience the problem (about 1 in 7 cars).

 

Head gasket failure (1, 2) is said to be related to the open deck construction of new engine blocks which pioneered in the mid'9's by many vendors. However the technology was not well controlled and many of the vendors have had issues with gasket leaks due to the smaller contact surface, and getting the gaskets right took some time (Nissan VQ, Dodge Neon 2L, Honda 1.3L).

 

New replacement multilayer steel gaskets from the dealer solve the problem definitively, as the problem seems to have been understood and solved, but it will cost about $2000 to do the replacement (engine drop, resurface, and reinstall, though it could be done on the car).

 

Details

 

This is a detail per engine model (maybe not exact). It will be hard to tell which model you have anyways, and not needed.

 

a) EJ22* - 2.2L 4 cyl SOHC 135HP/140ftlbs (most solid & non interference)

Legacy 90-96

Impreza 95-01

NO Gasket problem on the older ones, rare on newer models

 

EJ251 - 2.5L 4cyl SOHC 155HP/155ftlbs

Impreza '00-'02

Forester '00-'02

YES Gasket problem: external coolant leak

Non turbo EJ25 engine.

 

C) EJ252 2.5L SOHC

Legacy '00

YES Gasket problem: external coolant leak

 

D) EJ253 2.5L SOHC

Impreza '02-'07

Legacy '01-'02

Forrester '99

NO Gasket problem past 2003

Designed to take turbo boost.

 

E) EJ25D 2.5L DOHC

Legacy '96-'99

Forester '98-'99

YES Gasket problem: Internal leak/blown

 

F) EJ25E 2.5L DOHC

Impreza '99-'01

Forester '99-'00

Legacy '00-'01

YES Gasket problem: Internal/blown

 

G) EJ255 2.5L DOHC turbo

Impreza '06-Now

Forester '02-Now

Legacy '05-Now

NO Gasket problem

Designed to get turbo boost.

 

H) EJ257 - 2.5L DOHC turbo 300HP/?

Impreza WRX STi '04-Now

NO Gasket problem

Designed to get turbo boost.

 

I)EG33 - 6-cyl

NO Gasket problem

G series are closed deck.

 

Getting rebuilt engines

 

http://www.ccrengines.com

http://risingsunengines.com

 

 

Interresting threads on HG and other common failures

 

Subaru Maintenance Schedule

EndWrench magazine: Timing belt procedure All *OHC, 2.5L DOHC (2), 2.2L overhaul

 

2.5L DOHC Head Gasket Failure *PICS*

Phase 2 2.5L head removal pictures (naked SOHC, many pics!)

 

Subaru 2.5L headgasket FAQ

New types EJ disasters becoming common (lists engine problems)

When was 2.5L Head Gasket problem fixed?

2.5L head gasket revised Phase 2 2.5L SOHC WWP-99 recall info, 100k waranty and info on SOHC vs DOHC gasket failures.

Help deciphering compression results Phase 2 2.5L SOHC: 175psi +/-7psi is normal. A big difference in compression is more a problem than a lower number.

Toronto: blown head-gaskets on Phase I & Phase II ej2.5's (How to avoid HG problems by tapping the coolant X-over tube, not confirmed)

 

Another scenario for the HG failure If you hear piston slap, listen in the belt cover. It could be bad tensionner, not piston slap, it could then cause overheating then HG failure. HG failure often happens when engine overheats. Also check/replace the radiator pressure cap (OEM), look for clogged radiator, etc. if the car keeps overheating.

Post 4, Post 2, Post 9: List of other problems listed by commuter, including piston slap (annoying) and torque bind ($1K! Detect before buying by driving in tight circles, forward and back, should not need gas, nor shudder).

 

Some of these threads are considered to be over-alarmist, as Subaru cars tend to be reliable workhorses in general, but they still list the issues that are frequent with the brand. Every car model will have its quirks that frequently pop up, so it's good to know them and learn to recognise them early.

[nipper]

The 2003's are suspicous. There have been some leaking Hg on a few of those.

 

A minor tehnicality.. blown HG is internal, leaking HG is external.

 

Once again its about 15% of US cars.

 

nipper

[idosubaru]

for ex that the gasket blows on all cars 96-02 around 100k:

that is certainly not the case. there's a higher percentage rate of headgasket issues with these motors, they are not "garaunteed to blow" at any mileage. use the SEARCH function, just above and to the center/right in the solid gray bar. you can search the New Generation forum and realize that there are hundreds of posts on this topic.

 

if it's a non-turbo engine, then any 2.5 liter engine from 1996 (first year made) to 2003 falls into this category. from 1996 - 2003 the only way to avoid the HG issue is to get a 2.2. i do not know anything about the turbo motors, NASIOC would be a better place to get more info on those.

[nipper]

Any car with an aluminum engine can blow a HG at any time. Any engine that blows one over 140K is more age related. Use the search, there are some rather extensive threads on this, and one where i explained what the cause is.

The only car from the 90's that you can say with any confidence that blows them all the time is a dodge neon (and chrysler wont even give you the time of day).

Not all subarus blow HG's. There is no fixed mileage point for it either.

Want to get away from blown HG, by a car with a cast iron block and head.

 

nipper

[sonyhome]

Ah a search . Well, there are TOO MANY threads on the leaking gaskets (sorry not blown) that I don't even know what search keywords to use . There's nice pics of the problem in the repair FAQ. There's even threads that discuss it but it seems contradictory, and none are exhaustive. I'll put a post with a few links next.

 

What's missing is a good FAQ writeup as to *which* 2.5 engine versions have bad HG, stickied in the main FAQ.

 

So the thing I haven't figured out is exactly which engine models are sold with the defective gasket that is likely to leak (from flawed design, not from pushing the car too hard and overheating it).

 

Also when I ask my friends about it, for Subies, it's not that rare. 3 out of 5 have had it happen, and it seems to be around 100k. Of the others, one just reached 100k, and another has the V6, so AFAIK, that looks more than 15%. The 1st year (96) is notorious. Also the '02 forester I almost bought at just 66k had that suspiscious leaking too.

 

Around where I live, a HG job is $2500 (dealer) and $2000 in a good shop.

 

Honda:

I don't know of such widespread problems on hondas for example. Solid engines. Heck they even turbo stock NA engines without destroying them. I know someone with a 360k miles stock integra with only regular service (he went through a half dozen timing belts!!!). Mine is 170k and going strong. People in my honda forum rarely talk of HG issues. Maintenance wise, the unusual thing is having to adjust the valves regularly (many cars "self adjust" now).

 

Neons:

I've had a neon'95, and was on the neons forums, and yes it was a known issue, and no it didn't seem as prevalent as it is for subies. It was because one spot on the block where the wall was a little too thin so overheating could do it more easily, and overheating could happen because of a $5 coolant pressure cap not set right or faulty. But muuuch cheaper to fix... And if I recall it was felt to be a regular maintenance check to do like the timing belt. That car had other reliability issues, that were OK if you stayed on top of it, not a bad car (stick only), but still. I don't want that kind of ************ any more, especially on a long haul where it could break in the middle of nowhere.

 

Shopping for a Subie in the 100k range now, I wanna know if I should list as a must that the HG was changed, like I ask for the timing belt, and consider suspiscious any car that did not?

[sonyhome]

As you can see below, it's *very* confusing. Some posts say DOHCs are failing, others SOHC. It seems EJ25D is DOHC, but I thought it was SOHC, and EJ255 was DOHC. Some posts say EJ251 is good, others it's bad...

 

New types EJ disasters becoming common

Phase 1 2.5 HG as low as 70k

Phase 2 2.5 HG as low as 60k, not so frequent

 

When was 2.5L Head Gasket problem fixed?

Internal leak: 96-99 EJ25D, the DOHC Phase I 2.5 engine

External leak: EJ251

Good: EJ253

ANY Subaru is susceptible to headgasket failure

 

How to positively Identify 2.5 Engine in 99 Outback?

'99 outback EJ25D DOHC blows gaskets

'99 forester EJ251 SOHC does not

'00 and beyond: EJ251.

 

2003 Head Gasket Failure

HG issue solved '03 and beyond

However this '03 has hg failure.

[nipper]

2.5L DOHC engines Blow the HG (internally)

2.5L SOHC engines leak externally

Turbos seems fine.

 

from 1997 it seems to 2003.

 

I dont see what the confusion is, i think your over thinking the issue.

 

nipper

[jon38iowa]

Having the '99 Forester myself (note midyear change for Subaru for this car- it has the phase 2 engine), I would be personaly be much more concerned with the dreaded piston slap/knock. Having had this myself, it would have been far more pleasant and less expensive to replace a bad HG.

Just my 2 cents

[idosubaru]

we are telling you that any non-turbo EJ25 from 1996-sometimes-in-2003 will fall in the category you're speaking of. if you go looking for debate s and information to contradict that you can find it. you can always find contradictory information on the internet about anything, particularly something like this with lots of oppinions and negative exeperiences. SOHC and DOHC does not matter. there are two failure modes dependant on model engine, but you didn't ask about that and that only muddies the water even more. either way, they are both headgasket leaks so i don't think you care which mode of failure it is.

 

i'll say it again, any non-turbo EJ25 from 1996-2003 (mid-year) fits in this category you speak of. you won't find more specific info on here because there isn't any. if you want turbo info i'd check elsewhere for more comprehensive info and experience.

[TheYeti]

I just used the search function for this very thing.... TMI out there.

[idosubaru]

I just used the search function for this very thing.... TMI out there.

 

the solution is not always starting another thread. for someone needing HG info, it is time well spent to sift through what is here. rarely does one thread bare out info from all of the most experienced people on the board.

[nipper]

the solution is not always starting another thread. for someone needing HG info, it is time well spent to sift through what is here. rarely does one thread bare out info from all of the most experienced people on the board.

 

http://www.ultimatesubaru.org/forum/showthread.php?p=577504#post577504

 

 

 

see i told you it was a recent thread

 

nipper

[sonyhome]

Waa interresting linky!!! So now I know what's open vs close deck

 

Now I know my Honda-93's D16z6 is open deck. I think I've seen pics of it.

 

I'm not just trying to start a new thread for the heck of it.

 

I'm saying this problem is in the mind of all prospective buyers knowing this issue, so it should have been FAQ'ed years ago. If not expect it to be asked over and over by all newbs!

 

Thanks for pointing to the piston slap. And I saw a bunch of Commuter's list of things that go bad, in a few of his posts, beyond the HG (like torque bind you need to check by driving in circles w/o gas).

 

I guess I prefer to have a leak than a blown gasket if I have to choose between the two. At least you can tell when your cat croaks drinking the coolant on the driveway instead of seizing:)

 

When I have a sec I'll update my 1st post to reflect what you guys just told me.

 

Thanks!

[sonyhome]

My first post is extensively updated with all that i've gleaned.

 

If a seasoned member can proofread and correct, i think it's ready to be FAQ'ed... I'm missing pics of SOHC vs DOHC engines (no big).

 

BTW, the linky on Hondas does not show any honda problems. Just discussion of wich engines are open vs closed and how to sleeve them (for turbos I bet).

 

Also: Timing belts are changed at 105K, right? Do we need to pull the engine or is boxter shape making it easy for DIY?

[nipper]

My first post is extensively updated with all that i've gleaned.

 

If a seasoned member can proofread and correct, i think it's ready to be FAQ'ed... I'm missing pics of SOHC vs DOHC engines (no big).

 

BTW, the linky on Hondas does not show any honda problems. Just discussion of wich engines are open vs closed and how to sleeve them (for turbos I bet).

 

Also: Timing belts are changed at 105K, right? Do we need to pull the engine or is boxter shape making it easy for DIY?

 

Not to pick on you, but since you want to profess some sort of knowledge you need to know what your talking about:

 

Honda:

 

http://www.aa1car.com/library/gasket_failure.htm

http://findarticles.com/p/articles/mi_qa3828/is_200208/ai_n9147036

 

You can do the HG in the car, but its easier to take it out. The dealership where my engine was reabuilt did it inside the car.

 

BTW I am an automotive engineer, so I have a reasonable idea of what and why these failures happen. I am not condemming all open decks, just open decks with thin cylinder walls or specific design criteria that we are not privy to (read educated guess). Not all subarus get 106 K timing belt changes, there are earlier that get them sooner. Also there are earlier subarus that may develop cracks between the valaves that may be a problem.

 

 

Wikipedia is not an engineering journal (not even a car magazine) and not always 100% accurate. Secondly you are still saying that all cars blow HG at 100K which is WRONG. 15% (20% in a study in germany) is not 100%. Also HG's that blow after 140,000 miles on any car is more likely due to age. There are many of us that don't have HG issues. I went 191,000 miles on mine before the engin threw a rod (old age). There are many others on here that can say the same thing.

 

I really dont see any redeeming value in this becoming a FAQ as it really isnt accurate. This topic has been discusssed and will continue to be discussed by people with many many years exp in the field at all levels. this is more alarmest then anything else.

 

Subarus are not "especially prone" to HG failures more then other cars with HG issues. The one that is "especially prone" is the dodge neon with an almost unheard of 80% failure rate (its actually considered to be 100% but i dont like absoloutes).

 

When people come here asking abour HG issues we tell them that its aprx 15% 2.5L DOHC that have internal leaks and about the same 2.5L SOHC that have external leaks with an aprox repair cost of 1500.00.

 

Piston slap has absoloutly nothing to do with head gasket failures.

 

Your comment on a compression test is wrong, as it is not the raw value of the numbers that are important, but the relationship to each other that is important.

 

On overheating, if the radiator is clogged from old age the car will run hot. If the T-stat fails to open that can cause over heating, which in turn can blow the HG (this is true of ANY car of ANY vintage). Failed water pumps are rare, but do happen. That is why we now have temp gauges on the dash instead of idiot lights, to monitor the engine.

 

Subaru is not a big car company. They don't have a lot of engine choices. Nothing personal but your post is a bit on the overkill side.

 

Also we have already critqued the "disasters" thread which was also overly alarmist.

 

Sorry for being blunt, just i see alot of misinformation mistakes and contradictions. Why buy a car that will blow head gaskets at any time?.

 

"I'm using Wikipedia's data + infering from stuff I read,

for ex that the gasket blows on all cars 96-02 around 100k:"

 

You cant say that then quote the 15% refernce later on. Lucky this isnt a term paper or else i would have to give you a poor grade.

 

 

 

 

nipper

[idosubaru]

i am in agreement with nipper and second his previous post. all that needs to be said is "all EJ25's from 1996-(sometime in) 2003 are suspect". there is no mileage gaurantee and not every EJ25 will experience this, so realize it's a small percentage risk and make your decisions accordingly based on all your variables...finances, resources, desires, needs, personality...etc. a break down of which models have EJ22's and EJ25's would be helpful, but the breakdowns of the various EJ25 designs is confusing and not necessary.

[sonyhome]

Well I don't know if you realize, but I'm making a real effort to glean infos to make something that could be useful for others looking into Subarus. That's my way of helping out.

 

I am trying to make it honest, so I've been asking input to fix the over-alarmist tone, and come to a plain fact post. I am not a mechanical engineer, and I am not a mechanic, but I am an engineer with formal training.

 

If you don't make a FAQ on the most asked question, people will continue to p**s you off with the same question over and over because the threads on it are just overwhelming and confusing.

 

I am sorting though a bunch of infos to make some kind of -erh- truth come out from what could be seen as statistical analysis of infos. I know Wikipedia is not god's word, it doesn't have much on Subies anyways, but it tends to be right just by the sheer number of people giving their 2 cents (it's a self repairing system).

 

If I knew it all I probably would not even bother to ask the question in the first place, right?

 

If you read the 1st post correctly, I do list the failure to be about 15%. Now I put it in bold letters so it stands out.

 

AFAIK, many subies for sale now are 100k~140k and it's a reasonable question to ask about the HG. I called a dealer and a reputable shop, and now the cost is 2.5k and 2k, so it IS a valid question to ask when you buy, and needs to be factored in. Prices have gone up or are more in my region.

 

And as for why I'd get a 100k mile subie if they all blow gaskets? I would not if it's not factored in. However they are dependable cars from what my friends say and would serve my lifestyle.

 

BTW, the engines in our honda models start at 1.5L, but most are 1.6L/1.8L which may be why I never really saw anything on HG's. One (read 1) guy threw a rod last year and the average age of our model I'd say is 10 years and 130k miles.

 

As for the other inexact infos like compression, it's what I understood from reading other threads, which are linked! I will try to correct them if I people are willing to give me the time of the day. I think you don't realize that the stuff you take for granted from surfing this forum for years, is that when you start it's all new and darn hard to find.

 

PS: I've re-updated the first post, I hope you think it's more fair now.

[idosubaru]

editing looks good, cleaned up well. don't know if there's a way to avoid it sounding like "all EJ25's" have an issue....maybe "may have an issue" or "have higher risk of HG issues"...something to indicate that plenty still go 200,000 miles without issue as well.

[nomoaudi]

And thus , it is safe to conclude (from the evidence stated above) all cars will have mechanical issues, maybe. :-p

 

It is smart idea to hedge your bets a little.

[sonyhome]

I've managed to tone it down even more. Now it's almost not scary

[mguy]

I want to applaud sonyhome's efforts and summary. As a newbie with no engineering training but interested in buying a over 100k mile subura, I had many of the same newbie questions which were not answered after browsing this site for over 5 hours.

[The Dude]

I owned a 99 Forester for 200,000 miles, and I currently own a 2006 Forester. Given a choice, I would simply avoid any car with a Phase I engine. Whatever the exact per centage is, the head gasket failure rate is just too high on the Phase I engine. Plus, with internal gasket failure the potential for bottom end failure due to coolant contamination is a real possibility. Not to mention that due to overly narrow oil channels the Phase I engine occasionally had a camshaft seize.

The incidence of head gasket failure in any year Phase II engine is much, much lower than in Phase I engines. When they do occur, head gasket failures in Phase I engines tend to be "external" failures, so at least there are no bottom end worries. I haven't heard of any camshafts seizing on Phase II engines, so I assume the oil channels were widened. All in all, I would buy a Subaru with a Phase II engine regardless of model year.

[nipper]

Good more for the rest of us.

:-p

 

nipper

[usaru]

At the risk of having someone burn rubber on my head I also applaud Sonyhome's efforts here. This is an extensively discussed topic with a confusing array of sometimes cotradictory information and opinions. A concise, systematic summation of the facts can only be useful to those new to the topic.

 

While Nipper and Grossgary's basic tenet that 'all that needs to be said is "all EJ25's from 1996-(sometime in) 2003 are suspect". ' sums it up, people need more info than that, particularly when it comes to buying decisions.

 

Also, for owners like myself, with 55k on the clock, looking at a distinct possibility in the future, I want to be as well-informed as I can before that possibility eventuates.

[mguy]

Follow-up question: After replacing the EJ25 with a new head gasket set, how long do you expect it to last? Will the head gasket blow again in approx 100k mile due to the design of the engine? Or will other parts of the engine fail before the new head gasket fails again?