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Phase 1 vs Phase 2 vs SOHC vs DOHC, etc


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I've seen tons of postings here regarding head gasket problems in Subarus. Can someone provide the definitive description of which model years had which phases of which engines, and point out which ones are known to have the head gasket problems and which ones don't (yet?) have the problem? :confused:

 

I'm particularly interested in anything to do with 2.5L, DOHC engines. When did the SOHC engine get dropped? When did the DOHC get added, etc.?

 

For the record, I have a 1999 Subaru Outback with 2.5L DOHC engine, auto. The car was manufactured in June of 1999 and I've heard throught various channels that cars built later in '99 are typically less problematic because SOA "fixed" the head gasket problems in late '98/early '99 (for what that might be worth!).

 

With only 38K on the odometer, I'd like to know if I own a "bad" Outback or a "Good" Outback? How the h**l can I tell? :temper:

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Legacy models got the phase 2 SOHC engine in 2000 with the new body style. Imprezza's and Forresters got the newer engine one year earlier. (99) All 2.5 are supposed to be susceptible, with DOHC taking more heat, but that may just be they have been around a bit longer, and average higher miles at the moment. The difference most often quoted, is that phase 1 leaks internal, combustion gas into coolant, and phase 2 leaks external, drip coolant onto ground. I have talked to my two local dealers and they say they have seen very few failures. I have a mid year 99 outback, and expect a problem eventually, but have nothing to lose in the meantime by just enjoying using it. The one useful advice I got from the one dealer, was that the vehicles they had seen with problems seemed to have more dirty coolant. I know the coolant gets dirty as a result of combustion gas in leakage, but he suggested and there may possibly be an advantage to keeping the coolant fresh to protect the (already marginal) block to gasket contact area. I have been changing out coolant on all my vehicles recently, as I have had a couple of heater core failures. Replacing them is a miserable job, and I've decided if I can prevent even one failure by keeping the level of corrosion inhibitors in my coolant up, I'd be ahead in the long run. One last thought on the subject. The internet is a great source of information and I love the input I get from message boards. The problem, is if you have 100 owners with no problems, maybe one or two will be posting to forums like this. If you have 100 owners with problems, maybe 20 will raise issues and make complaints. To a casual observer, you could get the impression that the failure rate was 90%, when in reality, it may be 25%. That's still a bad number, but I talk to lots of people anymore that are having head gasket problems on many different cars. The level of panic on this board is high, because Subarus didn't used to do this sort of thing.

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prepared me for the failure I had shortly after I got the car.

By the way my car had always been dealer maintained and had all factory fluids changed on schedule and still failed.

While it is true that more folks come here with problems I have frequented other boards in the past while I have owned particular types of cars.

I still do frequent the BMW M and Z board on Roadfly.

Just to use my last couple of cars as an example on the Jeep board I used to frequent I never saw mention of a head gasket failure, or a clutch failure that some one had not caused themselves. Jeep's other failures got lots of mention though.

On roadfly I have seen one head gasket failure on a BMW in the past few years when a guy blew his water pump and drove home.

 

When a car has a truly unusual number of failures of any item you sure see lots of mention of it on a board. On the BMW board there is no mercy given to gas guages that go nuts on overfill, seat bushing that move, and truly lousey Cd players that skip.

Here it seems to be clutchs, head gaskets, oil pumps that need seals, the plastic oil seperator, and water pumps.

And I do agree that it is shocking because Subaru had a reputation as being bullet proof. Hang on to those 2.2s you guys.

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SOHC came out in late 99 in the Outbacks. (old body style) There are many 99 that have the SOHC motor. The SOHC is also a better motor because less moving parts, and better HP.

 

Radiators that come on all Legacys are very thin. (single row) One good way to help keep the headgaskets from failing is to put a double core radiator. Keeping the engine cool can extend the life of the parts including the headgaskets.

 

 

Richie

Superior Import Repair, Inc

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  • 1 year later...

Hi ,

 

I have a 2001 Forester that had it's head gaskets changed at 95,000 km ( on warranty thank heavens) . This is higher mileage than average but mostly highway , driven by my wife , routinely maintained. Not impressed so far with reliability but my wife loves her car so I put up with the problems.

 

I personally have owned Hondas , Mazdas, Volkswagens and had alot less problems ( all went over 200,000 km with only routine maintenance) :

 

Sub 95,000 km issues :

 

ignition coil replaced

rear bearings

clutch shudder

head gaskets replaced

constant engine light due to fuel tank pressure/solenoids

sost brake pedal

rear tailgate lift cylinder - one side

4 new tires at 70,000 km

 

what's next ???

 

Bill

 

 

 

 

 

 

 

Legacy models got the phase 2 SOHC engine in 2000 with the new body style. Imprezza's and Forresters got the newer engine one year earlier. (99) All 2.5 are supposed to be susceptible, with DOHC taking more heat, but that may just be they have been around a bit longer, and average higher miles at the moment. The difference most often quoted, is that phase 1 leaks internal, combustion gas into coolant, and phase 2 leaks external, drip coolant onto ground. I have talked to my two local dealers and they say they have seen very few failures. I have a mid year 99 outback, and expect a problem eventually, but have nothing to lose in the meantime by just enjoying using it. The one useful advice I got from the one dealer, was that the vehicles they had seen with problems seemed to have more dirty coolant. I know the coolant gets dirty as a result of combustion gas in leakage, but he suggested and there may possibly be an advantage to keeping the coolant fresh to protect the (already marginal) block to gasket contact area. I have been changing out coolant on all my vehicles recently, as I have had a couple of heater core failures. Replacing them is a miserable job, and I've decided if I can prevent even one failure by keeping the level of corrosion inhibitors in my coolant up, I'd be ahead in the long run. One last thought on the subject. The internet is a great source of information and I love the input I get from message boards. The problem, is if you have 100 owners with no problems, maybe one or two will be posting to forums like this. If you have 100 owners with problems, maybe 20 will raise issues and make complaints. To a casual observer, you could get the impression that the failure rate was 90%, when in reality, it may be 25%. That's still a bad number, but I talk to lots of people anymore that are having head gasket problems on many different cars. The level of panic on this board is high, because Subarus didn't used to do this sort of thing.
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  • 1 year later...
SOHC came out in late 99 in the Outbacks. (old body style) There are many 99 that have the SOHC motor. The SOHC is also a better motor because less moving parts, and better HP.

 

Radiators that come on all Legacys are very thin. (single row) One good way to help keep the headgaskets from failing is to put a double core radiator. Keeping the engine cool can extend the life of the parts including the headgaskets.

 

 

Richie

Superior Import Repair, Inc

 

 

 

the sohs 2.5 came out in 1999 ONLY in the forrester and 2.5 RS....not the outback until 2000.

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the sohs 2.5 came out in 1999 ONLY in the forrester and 2.5 RS....not the outback until 2000.

 

This is actually true. I was under the impression that ALL 2.5's switched to SOHC in 99, but Jack is right, only the Forester and 2.5RS Impreza got the Phase II EJ25 in 99.

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i dont see the big deal, besides the inconveinence of it all. to me a car that goes for more than 60k w/o any major issues is a decent car. and the HG's are known to be prone to failure at about 80-90k. not a big deal, when they go bad, get them replaced. its really easy to see if you have the phase I or phase II EJ25, look at your timing belt covers, if you see 4 ciclre-like patterns(two on each side of motor) you have the DOHC motor, if only two like the EJ18 and EJ22, you have SOHC.

 

 

~Josh~

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