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Guest Message by DevFuse

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Is preventive headgasket change an option?

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12 replies to this topic

#1 JaapH


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Posted 23 March 2004 - 06:07 PM

I have a 96 2.5 Outback with 110k.

No problems with overheating up till now, but I just wondered if it would make any sence to change the headgaskets now. Also because my wife will start using it just for small trips (heating up/cooling down often)

As I would do the job myself, it would give me the time to shedule and prepaire at ease. But would I save machining the heads? Or do I still have to do that?

I figured It will cost about $200 on gaskets and $100 on oil and coolants. So not a huge amount. And the gaskets are in the mail right now (I like to have some cheap US-spares as I live in Europe).

I won't do belts, hoses, oil pump, pulleys, etc (have done all of them resently).

Does it make sence or am I just looking for an excuse to get my hands greasy again?

The Netherlands

#2 wrxsubaru


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Posted 23 March 2004 - 06:31 PM

If its not broke dont fix it, only probelms can happen once you open the engine up.

#3 Nuwan


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Posted 23 March 2004 - 06:32 PM

if you have the warning signs that they are going to go soon, and it probably will it makes sense to do them in advance and prevent further damaging the motor or warping the heads

my $0.02

good luck:)

#4 The Dude

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Posted 23 March 2004 - 06:37 PM

... if it ain't broke, don't fix it. I believe that one recent poster said that his 2.5 Phase I was on it's FOURTH set of head gaskets. Another recent poster wrote that his 2.5 Phase I was on it's THIRD set of head gaskets. So, it may be that the latest revision head gasket for the Phase I really doesn't permanently solve the problem at all. Some posters on this board have hypothesized that too much metal was removed when the 2.5 Phase I was bored from what was originally a 2.2L block. Due to small differences in materials and manufacturing tolerances, it appears that some 2.5 Phase I engines are OK, will others are beyond repair. So, it would seem that you are one of the lucky ones. At 110,000 miles, your head gaskets may well last the life of the engine or car. At the worst, the head gaskets blow, and then you replace them. The Nederlands are a small country, if your wife breaks down, how far away can she be?

#5 99obw


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Posted 23 March 2004 - 06:48 PM

I have given this some consideration myself. I think if I had the engine out for some reason, i.e. clutch, rear main seal, rear oil leak plate, I would take the heads off and have them checked for straightness and change the gaskets. I would probably also adjust the valves. Some level of valve job may not be a bad idea either. I really don't know if I would tear into a good engine without provocation. If we had good statistical data on Phase I head gasket failures a more informed decision would be possible, but we don't.

If nothing else, the DOHC engine is cool, and working on it is a joy. It would be a good learning experience. If I do it again I will do things differently, that's for sure.

#6 theotherskip


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Posted 23 March 2004 - 07:15 PM

the only cool thing about having my head gaskets go was getting to tear into the engine, which was really fascinating. but i don't think i would risk screwing anything up on an engine that is fully intact. it is a lot of work (probably 25 hours at a minimum for the average amateur), and any number of things can go wrong.

many people can nurse it along when it does go by keeping the coolant topped off. i got by for about a month while i got parts together and figured out what i wanted to do.

#7 hb_kim


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Posted 23 March 2004 - 08:07 PM

In fact, the most effective preventive maintenance would be bleeding air properly from cooling system. This may not be as easy as it sounds. Very small amount of air in cooling system can cause the cooling system malfunction.

So I was hoping for someone to develop a permanent cure for this and I think this is it.


At the last part of the article, there is a mention about air purge valve or something like that to solve this problem.

I asked the author of the site about detailed pictures and how-tos. Right now, he has some trouble updating his web site but he will give me an update when he is able to upload the information.

I will never touch my cooling system (which was serviced by dealer recently) thus introducing air, until I get this modification done to my car.

Or, could someone more mechanically intelligent figure this out and post how-to for dummy? I'd be much obliged.

#8 Commuter


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Posted 23 March 2004 - 09:57 PM

The 1996 OB engine had 10 less hp (155 vs 165). I don't know how many were sold, but I think the sales increased in 1997 and 1998 as their popularity grew.

I haven't heard of too many failures on the 1996 model. But there is no way for me to know if it is simply because there are less of them around, or because the engine is a bit less powerful, or both.

The Phase I head gasket failure is exaberated by "load" conditions. That is, hiway running, towing, etc. Operating that calls for more from the engine. The pattern often is that people can run around town all day long with no problem, for weeks or even months on end, then the one day that they hit the hiway, the car overheats. In the early stages, the "leak" that opens up between the combustion chamber and the coolant passages doesn't even exist until the engine is being pushed.

Therefore, I would be "less" concerned if the car is about to see duty which is short trip driving. I'm assuming that these trips are not hard running trips (you don't say what sort of driving). There is credence to "if it aint' broke, don't fix it". Keep an eye on the coolant and expansion bottle. Watch the temperature gauge. You might install a more sensitive gauge if you like. Start a savings fund for the "head gasket repair" if you want. If it happens, you will not be hit so hard. If it doesn't, you have some cash that is still yours.

Edit - I see you are in the Netherlands. I know that some of the world gets the models a year before we do in North America. Hence, I'm not 100% sure what hp your engine has. (And the standard for rating is a bit different in Europe too.)

My 2 cents.


#9 Setright


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Posted 24 March 2004 - 01:39 AM

Don't upset the balance of a working engine!

But keep the HG set handy, and put money aside for the day it might blow.

#10 JaapH


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Posted 24 March 2004 - 01:46 PM

Well all your 2 cent advices add up to a dollar.

Just to give some answers to your questions above.
My car is US built (private import when Outbacks were not sold here).
I have used it under heavy circomstances (towing a 2200 lbs caravan up a 10-12% for 30 minutes was max. Boy, did the engine smell after that!)

Yep Holland is small but I don't care were it hapens, but when it hapens.

A short drive is a '3 minute to bring the kids to school drive'.

I agree that most of the time I have 'that last bolt' that gives a problem, so I better don't touch. It will not improve for the new gasket is not proven to be better.

I like the idea of a temp alarm but the info from HB Kim is the best and I believe that (is your real name Dr Phil?). Its a real eye opener and explains a lot.

This is that vital piece of information:
."....So trapped air causes head warp, which causes air to enter the cooling system. It was pretty amusing that at the same time I discovered this entrained air sensitivity in the 2.5 engine, so too did the auto dealers. Head warp caused by customers changing their coolant is now the number one warranty item with this engine. All caused by an engine block that was not plumbed to dynamically remove air from the high point. Subaru has since changed their cooling system design.

It's essential that the 2.5 liter coolant crossover tube atop the engine be drilled and tapped. This allows user to add a small tube from there to the coolant reservoir. Any air inside the engine block then automatically purges. Proof of effective purging is that I can now drain all the coolant from the entire sys, then refill. Every drop can be refilled without hesitation. Before adding this air purge, I would end up with a few cups of fluid that I could not get back in to the system. Also, I now can't get the engine to gurgle after a hot shut down...."

This I will do. I will drill that hole and put in a smal bolt just make sure I bleed all the air out. And if I can't reach that point a small hose with a plug and clamp should work. You won't need a big opening.

Thanks for all this advice. For me the misterious headgasket problem is solved

(From that small country on the otherside of that big lake)

#11 teasdam


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Posted 24 March 2004 - 02:32 PM

I haven't touched the cooling system on our outback but I was thinking...couldn't a guy just raise the front of the car to make the radiator cap the high point? Say, drive the car up onto some cheapo ramps from the parts store, or maybe park on a hill with the front of the car on the high side, and then try to fill coolant? Eventually it should burp through the cap.

(Then again some of these newer pressurized system may be different. I'm actually picturing my old Chevy setup as I type)

#12 JaapH


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Posted 24 March 2004 - 03:04 PM

Thats exactly the way I have been doing the bleeding. Because of a severe lack of hills in this country, I use a jack under the (optional) engine guard and jack it up way high.
Never had to add much later on.

#13 theotherskip


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Posted 24 March 2004 - 05:47 PM

i've seen that guy's article about not being able to totally purge the coolant system, but i don't buy it. mine failed at the bottom of the piston:

heads picture
gasket picture

at a place where an air pocket couldn't have developed. additionally, he has mounted the engine in an airplane, and there is no way of telling what angles it is mounted with respect to the mounting in an auto. overall, i think it is poor gasket design combined with a small sealing area.

i'm also assuming he bought a salvaged engine, and there is no telling if it already had a blown head gasket, which may lead him to misdiagnose the problem to be air trapped in the cooling system. and his multiple runs where he overheated it could have been what warped the heads, not air in the system. i just know that i don't think i would trust keeping myself in the air with a 2.5 providing the power!

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