1998 Subaru Forester - busted head gasket

So - I just learned the reason my car was overheating (after 3 trips to the shop and 2 new thermostats) is that the head gasket has blown. My Forester has given me very little trouble in its’ 150,000miles, and I was really hoping it would last me more than 200K.

At this point, I’m really not sure what to do - if I get the head gasket fixed, are the old parts of the engine going to hold up to the pressure? How far can I expect the car to take me before I have to sink more $$ in, or before it’s time to retire it?

The car is paid off, and I really don’t want a car payment to add to the bills. But I also can’t afford another repair like this in the next year.

Any advice as to the longevity and/or complications of a repair job like this are greatly appreciated!

If you want to keep the car for at least another three years you should consider getting a rebuilt engine. It is like getting a new engine for the car. Here is a link to some folks that are very well regarded in the Soob owners circles. They may not be the cheapest but they are among the best rebuilders and very customer oriented.

If you do replace the engine you might want to consider replacing the radiator also. You will have a 3 year warranty and hopefully no worries for a long time.


Subarus of that age with the 2.5 liter engine are known for having head gasket problems. Ours started leaking at about the same mileage as yours. The repair bill was about $1,500. Unless you repair it, your Forester will be impossible to sell. Although there is no guarantee that it won’t cost you more money in the future, I don’t see how you can get by any cheaper. Anything you buy for the cost of Subaru repairs will be in worse shape than your own car and will also need expensive repairs.

Well, there are other reasons for overheating other than a thermostat. Cooling fans inoperable, clogged radiator, etc. I would be suspect of a shop that required 3 trips and not one, but TWO, thermostats? It sounds to me like someone is wild guessing and a “bad head gasket” is often a whipping boy during the guessing process.

Provide some details on the overheating. In town only, highway only or both. Overheats even when the heater is on?
Overheats every time the car is driven or is it erratic? Any loss of coolant or boiling over?

Thank you for your replies! To answer a couple of questions:ok4450 - yes to everything. Except it only overheads when driven, not when they run the engine in the shop (why they didn’t catch it before, they tell me). But it would overheat in my 3 mile commute to work. I’m planning to take it elsewhere for a second opinion - I’ve been checking around and apparently there is a superb shop for japanese cars close by - wasp automotive anyone?
I’m realizing I need to have this fixed, whether I keep or sell the car. However, I don’t want to keep an unreliable car anymore than I want to buy a new one. I’m worried about other parts failing due to the increased pressure of a new seal - is there precedent for this after a head gasket repair?

" I’m worried about other parts failing due to the increased pressure of a new seal - is there precedent for this after a head gasket repair?"

No, you really don’t have to worry about that unless you only have one head done. If only one side is leaking and only it is repaired it is possible the other side may have a problem later on but then it could go on without any trouble. You just don’t know for sure unless it is redone also at the same time.

Since you really don’t want to have new car payments but want good reliability I suggest you look into replacing the engine with a totally rebuilt unit as I suggested in my first post. It will cost more than just having a headgasket replaced but you will have a 3 year warranty, on the engine at least, just like a new car would. You get the benefits of having a new engine at a fraction of the cost of a new car.

It is possible other things could be a problem later on but going on Subaru’s past history for these models you are facing the most common complaint with them, the headgaskets. Revisions in the gasket design have solved the problem now and things are better. The rest of the vehicle shouldn’t be a problem. The CV joints may need to be replaced later on but the replacement cost isn’t too bad to have that done. Even though the mileage is getting up there on the car I think you will be good to go with a rebuilt engine installed. You will also get a little better price for the car when it comes time to sell it.

A faulty head gasket can cause a vehicle to overheat but it should do this all of the time including running it in the shop.
Overheating when driven usually points to an inoperative cooling fan or a clogged radiator.
With cooler weather coming on and if the Defroster is used, a car can overheat if the fans are not working. The reason for this is that the air compressor is energized and the fans are required to hold the condenser pressure and temps down.

Here’s a couple of things you might do yourself. Loosen the radiator cap (the engine MUST be cold after sitting all night) and release any pressure that might be in the cooling system. (Of course, if there is any pressure in the system after sitting all night then obviously the cooling system is maintaining pressure and you don’t have a head gasket leak.)
Tighten the cap, start the engine, and allow it to idle for about 30-45 seconds. Shut it off and loosen the radiator cap again. If you hear a faint “hiss” sound then you may have a leaking head gasket.
After that, start the engine and make sure the radiator cooling fans are running when the mode control is in the A/C, Bi-Level, and DEF positions.

There are several methods for determining a head gasket problem so it should not be a guessing game. A compression test, vacuum test, hydrocarbon test, and cooling system pressure test can be performed to verify a head gasket problem along with a visual inspection of the engine oil and spark plugs. IMHO, all should be done before telling someone they have a bad head gasket.

There are issues that can exist with a head gasket (external leaks, etc.) but this has no affect on the engine unless the external leak is causing a low coolant level or is causing the engine oil to be diluted with coolant.

Hope some of that helps anyway. :slight_smile:

DON’T PAY FOR HEADGASKETS!!! We are a Subaru specialists shop, and that is ill advised! If you do indeed have an internal engine leak causing the overheating, it could be a headgasket, BUT BUT!!! those engines are frequently known to have cracked engine blocks!!! Headgaskets do happen but more often it’s a block. You may spend all that money on headgaskets and not change a thing. There is no way to tell which is it. The best way to fix it right if it IS an engine problem is a used low milage engine. We’ve started using these imported from Japan engines with 30k miles on them with excellent success. Lots of places sell these things.

Subaru’s have been blowing their head gaskets since day one. It’s VERY common for them to have this problem.

Idling at the shop might not expose this problem as there is very little cylinder pressure during idle…

Perhaps Subaru owners should have the heads re-torqued every 40,000 miles, something like that, in order to reduce this problem. Don’t expect Subaru to ever recommend this, as this would be admitting they have a design problem. I feel the expansion and contraction of the “pancake” aluminum engine slowly stretches the head bolts and their clamping force is reduced until the gasket blows…The ones I have checked have ALL been well below torque spec. ANY overheating episode, for whatever reason, will loosen the head bolts and lead to gasket failure. It’s just the nature of the beast.

The reason older Subarus go through head gaskets is due to poor casting practices. The newer castings (702+) don’t have the issues the older ones did.

I’m going to agree with Caddyman here. Subarus have been blowing head gaskets on and off since the early 70s.
Back then they used the wet sleeve engines and these would start leaking no matter what; and the recommended procedure was to retorque the head bolts every 15k miles. They would still blow.

In the late 70s things improved a bit. In the early 80s they started weeping oil from the 1.8 engines due to a head gasket redesign and only in some cases. Later on the situation became even worse.

What was the deciding factor? IMHO, it has to do with cylinder head torque. The early wet sleevers were beyond hope but in the late 70s the wet sleeve was done away with. Cylinder head bolts were retorqued at a 1000 miles just like the mechanical lifter, early 80s engines were. No problems with head gaskets.

Moving on into the future, cylinder head retorquing was eliminated on both the hydraulic and mechanical lifter engines and this is the cause of a lot of those problems IMHO. An aluminum block and aluminum head is going to have a lot of movement due to thermal expansion and no one can tell me that TTY head bolts are not going to change their properties.
Why did Subaru eliminate their head bolt retorquing recommendation? Because Subaru was paying for it at a 1000 miles instead of the customer and it’s another way of saving money.

Why else would Subaru recommend a head torque for years and then turn around and say it’s not needed on the identical same engine. Subaru at one time was saying retorque head bolts on a mechanical lifter engine but not on a hydraulic lifter engine. Same engine, same heads, same pushrods, same head bolts and head gaskets, etc. It makes zero sense.

OP, a head gasket problem is easy to verify with the tests I mentioned, assuming your problem is not fan or radiator related.

Right you are… Early Subaru flat fours were not uncommon to have headgasket leaks with the 1.5, 1.6, 1.8 and 2.2. When the 2.5 came out in the mid90’s, headgaskets became MUCH less common. Yes they still happen and HEY they’re 10 years old. MOST cars need a headgasket by the time they are 10 years. Still the first early 2.5 has a tendency to develop block cracks, not headgasket leaks. Around '00 the blocks were changed and don’t cause problems, but now headgaskets have become common again. There is a factory bulletin and extended warranty on '00 and up Subarus for headgasket leaks.

One way we test for possible headgaskets is to pull the spark plugs while pressure testing the radiator. Leave the radiator under pressure for a couple of hours. If you have a leak into the combustion chamber you’ll know it!! This is good for finding very small leaks. We also have a tool that you put over the radiator filler neck while the engine is running. It sucks the air in the top of the radiator into a chamber. The fluid in the chamber changes colors if engine combustion vapors are present in the radiator.

I’ve got a STANT tester that works pretty well. Head gaskets may often leak at places other than the combustion chamber though; external and on the ground or between a coolant port and oil return passage.

One thing I’m curious about since I’ve never seen it is this. Where exactly are these blocks cracking? Have these cracks actually been seen?
The only block problems I’ve seen is when someone has tried to pry crankcases apart and missed the hidden bolt or when a crossover port O-ring was leaking. Just wondering.

It’s a hidden mystery. Wherever they crack has been undetectable on any engines we’ve torn down. '98 and '99 models have been the most common. You definitely could luck out and just need headgaskets. But what do you do when you pull the engine, pop the heads, have them pressure tested and pass fine and the headgaskets look okay?? It happens alot. Now you have the labor of tearing an engine down and machine shop inspection, and you’re still replacing the engine. Also consider maybe it goes fine and just the headgaskets DO fix it. Now you have a fresh top end on a 200k block. BAD IDEA!!

Somehow the turbo Subaru engines have avoided this problem. Its beyond rare but they are fortified apparently.

So it’s being assumed the block is cracked because coolant is diluting the engine oil? What about the heads losing a bit of their torque and coolant seeping from a coolant port down into the oil return passages?
That was a very common problem with the old wet sleeve Subarus and could occur even with the head gasket appearing to be in perfect shape.
I’ve also seen it on a number of other makes and models.

What about cylinder head warpage doing the same thing? Just about every Subaru I’ve torn apart was out of specs on cylinder head warpage. Warped head leads to leaking head gasket.

I understand your point completely about doing a top end and being stuck with a junk engine, but I don’t have a problem with head gaskets only if it is known for a fact the engine was not knocking, did not have coolant diluted engine oil, and had not been suffering coolant into the combustion chambers for an extended period of time.
This is often a tough call since the mechanic may not know the entire story, and believe me, I’ve seen more than one Subaru owner lie their tails off in an attempt to whitewash the problem. I guess they figure if they make it appear trivial (why no, it just overheated around the corner from here and I pulled right in) then the repair costs will be less.

Very valid points!! These are pretty simple heads to pull and inspect also, so the potential expense on exploritory surgery doesn’t really contribute much when accounting for engine replacement costs.

We have a '96 Legacy with 300k miles and a '98 Legacy with 200k miles we use as free loaners for our customers. The '96 got a used engine 3 years ago to reapir a cracked block. Then it came back a year later with a overheating problem again. Tore it down… another cracked block. We had the heads gone through and put in a new short block. Out of the dozen or so 2.5 engines we’ve fixed, I’ve never had a ‘2.5’ with a warped head.

Another issue with the early 2.5 is a significant piston knock because the dummies used WAY too short of pistons with virtually NO skirt. We have a number of reasons for suggesting low mileage transplants on those couple of year models.