duniguy

Hi, I have a 98 Forester S with a little over 135k. miles.

I am no mechanic, but I have done a few small jobs.
Last year my forester overheated one night on my way to a friends house. I let it cool for a few hours and then tried to drive it home and it overheated about 5 minutes after I got on the highway.

I had it towed to a garage close to my house. The guy there said he did a full diagnosis. He said it was hard for him to get it to overheat but he finally did some kind of infer-red scan on my radiator and said it was blocked, and I needed a new one. I had never heard of such a thing. I just thought I might just need to do a coolant flush.

I did the flush and also put in a new thermostat. It drove well around town but started to overheat about after 5 minutes on the highway. Someone told me it might be the radiator cap, so I changed that, and its still overheated.

I then brought it to the dealer to try and get some professional advise. They said it was a head gasket and it would be $2,200 . Their reasoning was because of seeing bubbles in the radiator. I told a car handy friend of mine and he didn't believe it. He wanted to do a pressure test himself. He did the test and said all the cylinders checked out.

It still overheats, but now it only overheats when you are going under 2500 rpms!

I have no idea who to believe or what to do now.
Any advice would be great.
thanks!

adc

It is possible that it's a Head Gasket. But I would do a Used Oil analysis Blackstone Laboratories If it is just leaking at the exhaust part a UOA may not show anything up but that's unlikely.

I assume you did the CamBelt at 105K miles?

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pleiad7

Yep, head gasket... welcome to the club.

Read up here: Head Gasket Problems - Subaru 2.5 liter engine - Phase 1 and 2

__________________
-Silke
04 FXT PP PSM ~ "Subed"
98 Forester S ~ "Slynki"
92 SVX LS-L ~ x2

duniguy

So the "infer-red" diagnosis and my friends pressure test were wrong?

Real Lyte

If the had gaskets were never replaced on ur '98, it's gonna be sooner or later. VERY common problem of '98 and '99, mine were replaced at 80k.

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flstffxe

Is no mystery on a phase one EJ25, if it is not some thing simple like a bad cap or a low due to a leaky hose rest assured it is 99.99999% due to a bad HG.

Not necessarily wrong, just inaccurate.

The inferred(assuming inferred temp gun) is just pointing a the gun at the radiator and looking for hot and cold spots. There will always be dead zones in a radiator that have minimal flow and thus read cooler then the areas with a higher flow of coolant, diagnosed as a blockage.


The pressure test is not 100% accurate either. A EJ25 Subaru engine may only suffer HG leak/s under certain conditions IE: from xx degrees to xxx degrees during warm up or at temp under a heavy load and so on. So it is possible it passed the pressure test with out fail because the engine was not under the conditions required for the head gasket to leak.

I have done HG on a Baja that the HG only leaked during warm up if the engine was stone cold <40 degrees F. It would start to leak once the engine was about 80deg. F and stop at around 120deg. F. It would only leak if the engine was left to cool all the way down and if the out side temp was less then 40 deg. F. You want to talk about banging your head against the wall to figure that one out.



I would be willing to bet that with the bubbles seen in the radiator that it is either a HG leak or a air pocket trapped in the cooling system, I lean towards the HG leak.

If you want to know for sure take a sample of the coolant and send it to blackstone labs to be tested for hydrocarbons.

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Geezer

Here is something else to consider:

Before I discovered Subaru, I use to drive Toyotas. The last one I drove was a 1986 Camry that at about the same age as your Forester developed an overheating problem where the temperature gauge would occasionally work slowly up into the red zone and stay for awhile and then come back down.

The mechanic I consulted immediately opened the hood and ran a finger across the radiator fins. The aluminum had rotted to the point where it just flaked off wherever he touched it. The only part of the radiator that functioned was the tubing inside. A simple radiator replacement solved the problem completely.

Geezer

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Griff (The Geezer)
Drives a 2009 Forester XS Ltd.

dbtuned

Not really a mystery...and here's what it looks like:





These pictures are from a 98 RS that I finished up on Monday.
The radiator was partially blocked, preventing proper cooling.

BTW, compression test indicated no problems.

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DonutKing

So... Im getting another one of the foresters....just cant let go.. Im finding alot of them with the famous hg problem... how long can these things go before catastrophic problems.
If I can get independent shop to do it for about a grand then ill have them do timing belt as well.

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adc

Make sure you get a good mechanic. I would be less than enthusiastic taking it to someone who didn't specialize in subarus. Make sure they warrant the job. Consider going with genuine Subaru parts vs after market ones.

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flstffxe

I second adc 100%.

The timing belt has to come off for the HG job any way. As long as the water pump, hydrolic tensioner, idler pulleys, crank seal and cam seals are in good the install of the timing belt should be at no charge other then the cost of the timing belt it self.

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duniguy

So did you come to this diagnosis because I mentioned the infer-red test?

Also, I forgot to mention that the heater turns off when it overheats, and then when you drive it over 2500 rpms it cools down and the heat comes back on.

Ginnydog

Hey everyone, mine's doing the same thing...it's got 277,760 miles on it...maybe it's time for a new subaru :(
Ginnydog