Changing headgaskets 97 outback ltd

[Digger19]

I have a 97 Outback Ltd. Engine is a 2.5 DOHC. Can I replace the head gaskets with removing the engine even though removing it may be easier?

[davebugs]

I wouldn't on a 2.5. It's just easier to pull the engine. Reseal it up (including the baffle plate). I think you do a better job with the engine on a stand. When it comes to cleaning the surfaces, the bizarre torgueing sequence, etc.

 

Just much easier to work on, and I think it makes a better job of it.

 

I don't try to impress anyone. I like to do things one time and correctly. My opinion is those odds are improved with the engine out of the car. Has to much less frustrating. I think you'd add more time to the job trying to leave it in the car rather than just pulling it.

 

Dave

[nipper]

A more important question, how many miles are on the car? Have you done a wet/dry compression test to try to gauge the health of the piston rings?

[dave833]

Pulling the engine's really very easy. I just pulled a 2.5 from a '97 and it took me 4 hours start to finish- I'm sure others can do it faster, but I've pulled Honda/Acura engines and they're MUCH harder.

 

On the other hand, I did the head gaskets for an SVX EG33 with the engine in the car because I didn't have access to a hoist. I jacked up the engine/trans as far as it would go to clear the frame rails and it wasn't too bad either.

[Digger19]

A more important question, how many miles are on the car? Have you done a wet/dry compression test to try to gauge the health of the piston rings?

 

Car has 215k km. Have not done a compression test. Only assuming it is head gasket as car started overheating on acceleration and when speed started to get over 90kph. The temp fluctuates quite rapidly between normal to slightly low to very hot depending on load. When I loosened the radiator cap antifreeze wanted to bubble out of the rad. I assume rings are still good as car does not use any oil( have used synthetic from new). Right now I just need to get the car going as it is our families only vehicle.

[nipper]

The reason i ask is because when you do HG's on a high mileage engine, you raise the compression slightly. If there is over 160,000 miles on a sooby, I try to stear people to another engine. I dont want to hear that they are buurning oil, 100,000 Km = 60,000 miles ?

 

Also if the engine has been overheated repeatedly a compression test will tell if the cylinders have been scored, as all of them would be scored if the engine was cooked.

 

It sounds like you should be OK. Remember to change the oil after the engine is all together.

[idosubaru]

this doesn't sound like typical EJ25 head gasket failure. they normally overheat and peg straight to red, nothing you can do about it. they don't typically waver at all or only do it under load.

 

you could have some other problem like a clogged radiator or bad thermostat or just air in the system. replace the radiator cap?

[abog]

Changing head gaskets does not raise compression. The bore / stroke and cylinder head cc's are not changed. If the cylinders are low on compression it is due to wear in the bore / rings, or bad valve seal. When a subaru head gasket goes bad on the 2.5, some cylinder pressure is bled off into the water jacket. This loss is slight and generally if the engine has not been severely overheated will not notice any operation difference when resealed. A compression test is a good idea on any engine before a teardown regardless of mileage. If you are not using oil or have a definite power loss , you are probably fine with new gaskets.

[nipper]

WHen you have the Headgasket job done, the first thing you do is have the heads seant out to be rebuilt. The surface is remachined to the proper finish, then if necassary, also restored to the proper flatness.

 

Also the heads are rebuilt which means a valve job. Between these two you are restoring and or increasing the compression to factory specs on 1/2 the engine. you have done nothing to restore the deal at the rings to refresh them.

 

On a high milegae engine (which this is not) everything wears equally. Just rebuilding the heads and losing some material can push the compression up to where the rings may have blow by.

 

If you are doing a HG job without resurfacing/refinishing the heads you may as well throw your money down the toilet, as it is only half a job.

 

So yes it will raise/restore compression form what it was before the HG job.

 

Just speaking form my 20 years of pulling a wrench and many years in the auto engineering field.

 

nipper

[Digger19]

Radiator took about 2 quarts of fliud. I am sure this was the cause of the overheating. Question is, where did the antifreeze go? At times I can smell the antifreeze outside the car after I shut the engine down. Does this mean an external leak, or would a blown head gasket let some pass out the tailpipe? Could a bad rad cap cause fluid loss?

[mdjdc]

I agree that you should resurface the heads, but the local dealership doesn't typically do that for a head gasket job. The master Tech told me that he rarely ever has a problem with the heads warping and only if the car has been driven hot or has been overheated weveral times.

 

I have done several without resurfacing the heads because the people didn't want to pay for it and none have come back.

 

Just my 2 cents.

 

 

WHen you have the Headgasket job done, the first thing you do is have the heads seant out to be rebuilt. The surface is remachined to the proper finish, then if necassary, also restored to the proper flatness.

 

Also the heads are rebuilt which means a valve job. Between these two you are restoring and or increasing the compression to factory specs on 1/2 the engine. you have done nothing to restore the deal at the rings to refresh them.

 

On a high milegae engine (which this is not) everything wears equally. Just rebuilding the heads and losing some material can push the compression up to where the rings may have blow by.

 

If you are doing a HG job without resurfacing/refinishing the heads you may as well throw your money down the toilet, as it is only half a job.

 

So yes it will raise/restore compression form what it was before the HG job.

 

Just speaking form my 20 years of pulling a wrench and many years in the auto engineering field.

 

nipper

[nipper]

Personally i wont do a HG job unless they resurface the heads.

 

I have had friends do it and had to deal with comebacks. On modern engines its the surface finish that is just as critical

 

http://www.aa1car.com/library/ic697.htm

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

[idosubaru]

yeah i think it's a low percentage thing, so take your pick/personal preference. if it was a significant issue and cause of failure then the "engine side" of the head gasket would have problems sealing i would think as well. no one on here is resurfacing blocks when they do head gasket jobs.

 

i typically resurface them, almost always. but the few i haven't have never had issues either.

[davebugs]

The "engine side" is one of the reasons that I always pull the engine.

 

Much easier to see the condition, clean the engine surface, etc. This "second" piece is often overlooked - especially if still in the car.

 

I'm 50/50 on sending the heads to the shop.

 

If they are out 4 thousanths after I clean them - off they go.

 

If I can run a compression check w/the engine in the car and don't like what I see - off they go.

 

I've had them wear a "ring" into the head - off they went.

 

They never seem to need seals so if they aren't warped, and clean up well I've stopped sending them out as SOP. I always send the radiator out to be cleaned/flushed/tested as part of a HG job. Whether the PO tried a sealant or not.

[subaru360]

Radiator took about 2 quarts of fliud. I am sure this was the cause of the overheating. Question is, where did the antifreeze go? At times I can smell the antifreeze outside the car after I shut the engine down. Does this mean an external leak, or would a blown head gasket let some pass out the tailpipe? Could a bad rad cap cause fluid loss?

 

Did it blow the coolant out of the overflow bottle? When the head gaskets are bad that is what they do. I would do a quick pressure test on the cooling system to be sure you don't have an external leak somewhere. If that is ok you are probably looking at the beginning stages of bad head gaskets.

 

Everyone on here has their own opinion on the best way to do the job. None of these opinions are wildly out of line. I do a lot of these jobs, several a month. I don't get the head resurfaced or do valve jobs for no reason. I just check them for warpage, clean the parts with a razor blade and brake kleen. I have done about 30 of them like this with no repeat failures. My reasoning is that the factory finish on the heads is better than what the typical local machine shop can do. Also these heads are very short, if it got hot enough to warp them, I don't want to repair the engine. At that point I just replace the whole thing with a 2.2 engine.

[Digger19]

The overflow was almost empty. Topped it up and took the car for a drive. Temperature was normal. There was no bubbling in the overflow at all. No white smoke out hte tailpipe. After I shut it down could definitely smell antifreeze in from the front of the car. Nothing dripping on the ground, but am guessing I have a leak somewhere.

[davebugs]

Take it for an hour ride. Usually doesn't happen for about 45 minutes.

 

Highway speeds preferred. Watch the gauge. When she decides to get hot she will. It's not uncommon for the heat to vary a little like normal for the first 30 minutes so don't let that give you a false sense of security.

[abog]

Subaru 360 is right on. I began working for Subaru dealerships in 1982, I have been a Senior Master technician since 1994. I have done hundreds of head gaskets on all subaru vehicles over the years. All the advice that I give people comes from massive experience with the product. Take from it what you will, but what I have seen in a lot of cases is that people over repair vehicles, either to safegaurd themselves or to give themselves a sense of security in their vehicle. There are many different opinions of how to do a job, as long as the vehicle is repaired they are all ok. My preference is to do what is necessary to repair the problem for the customer, not to add repair work that in my opinion is unnecessary. Oh and by the way, my work has always stood for itself with no comebacks.

[msmithmmx]

Please listen to Nipper and take my advice. I did a HG on my 98 Subaru, 200 K on the motor. The engine no longer over heats but now am burning some oil. Its my extra car so its not killing me but.... The next time I do this on an older moter I will split the block and do the rings.

[abog]

That is why before tearing into any engine, you should do a compression and leak down test. These tests are a pretty good indication of the condition of the cylinders. It is very common to see ej series engines with much higher milage, but no two are the same. Oil usage in higher mileage engines is not abnormal. Rings will help if leak down and inspection shows cylinder wear, but almost always the cylinders will be worn and have unacceptable taper. When you get to this point the condition of the crank, wrist pins and bearings must be factored in. Unfortunately the cost of a rebuild very often is not economically a sound decision, so people opt to replace. There are a lot of used engines around for these cars and that is what most people will do for replacement. While many are good units, many are not. Typically any used part is always a gamble and has to considered as such. The end of this is, if you are going to do head work, you are essentially just doing half of the job and the results will not be perfect. If you have a good running higher mileage engine that looks ok on tests, replace the gaskets and it will usually give you many more miles of reliable service. All of this is my opinion and everyone is entitled to their own.

[kingbobdole]

I didn't notice anyone jumping out there and saying it, but you cannot do a DOHC head job in the car. The rear lower bolt on both sides will just not clear... You might be able to jack the engine out of the cradle enough to get it but it's about a billion times easier to put it back together correctly with it on a stand. It's also not that hard to pull the thing.. last one I did took me like 45 minutes to pull.

 

Ohh and as for the poll, I always have heads machined.

[Digger19]

Found a leak in the radiator. Bought a new one. Have not had any overheating problems since although today after I shut the car off there were some slow bubbling(1 every second or so) occuring in the overflow tank. Is this normal or is it indicative of an impeding HG failure?

[crash321]

Keep a close eye on your temp, coolant level, and really watch for coolant getting pushed into the overflow. If your rad was leaking, it probably caused the coolant to not go to the overflow. If you do start noticing that is does get pushed into your overflow, another member has suggested loosening your bleed screw on the passenger side of the radiator to prevent the pressure from getting to high. Just a little venting of that screw is necessary and keep your coolant full, that will get you by till you can fix it right.