just seeing if anyone has any experience with this....

 

i have a 98 forester with 130k. it has a new water pump, new thermostat. those repairs were due to some overheating issues this summer. i did a 27hr run from nebraska to california thru the desert. i wasn't totally shocked that it overheated.

 

it has been fine since those repairs until last week, i did a 90mile trip and came back with an overheating car. the mechanic pressure tested the coolant system and said it produced no leaks. it seems fine now but i don't have 100percent confidence with the car. any hints?

just seeing if anyone has any experience with this....

 

i have a 98 forester with 130k. it has a new water pump, new thermostat. those repairs were due to some overheating issues this summer. i did a 27hr run from nebraska to california thru the desert. i wasn't totally shocked that it overheated.

 

it has been fine since those repairs until last week, i did a 90mile trip and came back with an overheating car. the mechanic pressure tested the coolant system and said it produced no leaks. it seems fine now but i don't have 100percent confidence with the car. any hints?

Are your electric fans (behind the radiator)working? Every now and then I hear of people having issues with these on the Forester, though, mine have always performed well.

fans seem to come on and turn off.

is there a thermostat that activates them?

Not to jump to alarming conclusions, but you should check your overflow tank for nasty residue that might indicate a blown headgasket. The 98 Forester has the infamous phase I EJ25, which is known to develop HG problems. Usually, it will blow combustion gasses into the coolant, causing overheating, without leaking coolant back the other way, so it's hard to tell with a cooling system pressure test.

Not to jump to alarming conclusions, but you should check your overflow tank for nasty residue that might indicate a blown headgasket. The 98 Forester has the infamous phase I EJ25, which is known to develop HG problems. Usually, it will blow combustion gasses into the coolant, causing overheating, without leaking coolant back the other way, so it's hard to tell with a cooling system pressure test.

 

i dont consider that jumping to conclusions, on phase 1's that is the first place to look

just seeing if anyone has any experience with this....

 

i have a 98 forester with 130k. it has a new water pump, new thermostat. those repairs were due to some overheating issues this summer. i did a 27hr run from nebraska to california thru the desert. i wasn't totally shocked that it overheated.

 

it has been fine since those repairs until last week, i did a 90mile trip and came back with an overheating car. the mechanic pressure tested the coolant system and said it produced no leaks. it seems fine now but i don't have 100percent confidence with the car. any hints?

 

After any overheating event, I would check the head gaskets. My 1998 Forester blew a set at 184,000 following a minor overheating. Aluminum engines don't like excessive heat, ant the h. g.'s on the phase 1 2.5l are notoriously week.

 

BTW, if your fans weren't working properly, you would get a CEL.

I don't know that you would get a CEL if say the fan motor is bad or even disconnected? There is a matrix in the ECU that determines which fan(s) are on hi/low based on speed, engine temp, A/C compressor on. Usually they'll come on if the engine coolant temperature sensor (not the sensor for the temp gauge) detects 200 or 202 or something deg. F. or above. If that's working fine and it still overheats then for whatever reason the cooling system has exceeded it's maximum heat rejection capacity; that could be due to plugging, leaks, bad radiator cap, or any host of other issues.

I don't know that you would get a CEL if say the fan motor is bad or even disconnected? There is a matrix in the ECU that determines which fan(s) are on hi/low based on speed, engine temp, A/C compressor on. Usually they'll come on if the engine coolant temperature sensor (not the sensor for the temp gauge) detects 200 or 202 or something deg. F. or above. If that's working fine and it still overheats then for whatever reason the cooling system has exceeded it's maximum heat rejection capacity; that could be due to plugging, leaks, bad radiator cap, or any host of other issues.

 

When the relay to my fan went south, I got a CEL.

OK a few questions, has the raditor cap been replaced. has the cooling system been checked for trapped air. Next is not to do a pressure leakdown test, but to check for exhaust gasses. ALso remove and inspect the raditor to make sure all the cooling fins are in place, it is a little early to need a raditor but you never know. Check the raditor for flow too.

 

nipper

probably a head gasket but i'll admit i am jumping to conclusions.

 

best to start ruling out the obvious - fans coming on, thermostat, radiator, radiator cap, etc.

 

any belt noise, slipping, low voltage stuff going (loose belt)?

Have a hydrocarbon test done. That will rule out a HG.

hey forum.

thanks for all the input.

 

i think a hydrocarbon test sounds logical. i still need to talk to my mechanic about it. for now, all i've been doing is keeping a close eye on the fluid levels. i'm no auto mechanic but i certainly find this board helpful. thanks again. i'll post any results. car has seemed fine lately. no leaks. levels are fine. no white exhaust. power seems normal.

ok here's an update.

car overheated today after about 30minutes at interstate speed. the air temp was 10f. what's up with that? limped the car to a state park where i was expected for some trail work. a buddy had some antifreeze. added about half a container. limped it home at 60mph. no change in fluid lavel at that point. still haven't done a test for products of combustion in the antifreeze. so i haven't ruled out a headgasket, but i'm still not leaking. it starts fine, runs fine and the previous weekend i drove it extensively with no high temps. doesn't feel underpowered either.

 

but...i have a confession. i took the large plastic shroud off the bottom of the car under the engine bay before all this overheating stuff started. i put it back on this afternoon once i got home. i will feel real stupid if that is the problem solver.

ok here's an update.

car overheated today after about 30minutes at interstate speed. the air temp was 10f. what's up with that? limped the car to a state park where i was expected for some trail work. a buddy had some antifreeze. added about half a container. limped it home at 60mph. no change in fluid lavel at that point. still haven't done a test for products of combustion in the antifreeze. so i haven't ruled out a headgasket, but i'm still not leaking. it starts fine, runs fine and the previous weekend i drove it extensively with no high temps. doesn't feel underpowered either.

 

but...i have a confession. i took the large plastic shroud off the bottom of the car under the engine bay before all this overheating stuff started. i put it back on this afternoon once i got home. i will feel real stupid if that is the problem solver.

 

That shouldn't matter a bit. I'm still thinking head gaskets.

Nathan

That shouldn't matter a bit. I'm still thinking head gaskets.

Nathan

 

that's cool. i'll get it checked.

Sorry to hungry to read... but EJ-25s overheat hugely when they blow HG's...

Don't repeatedly overheat your engine. If it's the head gaskets, and it probably is, fix them. Only thing you're doing is moving from an expensive repair to a really, really expensive repair. Warped heads or a seized engine aren't going to help the situation. Given a choice between driving a car in for repair and having a car towed in for repair, I 'll go with driving everytime.

Don't repeatedly overheat your engine. If it's the head gaskets, and it probably is, fix them. Only thing you're doing is moving from an expensive repair to a really, really expensive repair. Warped heads or a seized engine aren't going to help the situation. Given a choice between driving a car in for repair and having a car towed in for repair, I 'll go with driving everytime.

 

word to that. id get it in there for a hydrocarbon test as soon as possible, and if it fails(even a little) leave it there, and save yourself a few grand:headbang:

the advice is appreciated. i've got the car scheduled to go in.

It has been reported here that HC tests don't always turn up a Subaru headgasket problem. When they just start to go bad the engine seals up when cold and the HC tests show nothing.

ok so...the car is in the shop. got a borrowed car. sweet.

 

like i mentioned before the coolant system shows no leaks. just did a pressure test on the cylinders, that also showed no leaks. no hydrocarbon test yet, so i don't have those results.

 

you'd think a pressure test on both the cylinders and the coolant system would reveal a leak if the head gasket was blown, right? test a cylinder and it should leak across the blown section of the gasket, right?

 

ok so...what if there were air bubbles in the coolant, wouldn't it overheat fairly consistantly?

 

ok so...what if there was a restriction somewhere in the coolant passageways in the block or heads, wouldn't it overheat all the time? or atleast all the time once the car was driven for 30minutes or so?

 

one thing i do know is that once i overheated the car for the first time this summer, simply replacing the missing coolant corrected the overheating. that being said, my understanding is most headgasket failures occur after an overheating event. so i could have blown the headgasket sometime after the initial overheating event.

 

my mech did notice one thing. when the plugs were removed, one plug in each bank had an electrode showing much more wear. might be unrelated?

you'd think a pressure test on both the cylinders and the coolant system would reveal a leak if the head gasket was blown, right? test a cylinder and it should leak across the blown section of the gasket, right?

 

linder and

 

Actually, no. The usual mode of HG failure for the series I 2.5L is a very small break between cylinder and coolant jacket - so small that it usually doesn't show in a compression test. Only the really high pressure of the firing stroke blows exhaust into the coolant loop. It's a nasty, "stealth" failure, that took Subaru some years to admit might be a fault in the engineering of this motor.

not to metion that it can seal up and only leak when it gets quite hot. It can also be so slight that it passes sniffer tests. A miserable job for a mechanic to find.

car is still in the shop. the hydrocarbon test was performed and it was positive. so despite a positive pressure test, we agreed it was time to go in.

 

so off came the heads. the block is still in the car. the mech is concerned about some suspicious marks in the cylinder wall of the drivers side rear cylinder. looks like a whitish line but it's not very defined like a crack. it's like it was made with an air brush. and there are more than one of these lines. two or three. maybe wear marks? it has fuzzy edges. so, they are having their engine head machining guy come over tomorrow to give his expert opinion.

 

it's also not obvious by looking at the head gaskets that they have failed. 3 of the 4 cylinders show evidence of burning antifreeze.

 

i'll continue to post updates. sure hope i'm not buying new heads or a block.

Another Sub soap opera "As the engine turns". That engine has over-heated a few times! Are you sure you still want to use it? You might want to start looking for a 2.2 and have that shop swap it. You can grab a JDM of EBAY for a few hundred bucks. You might get lucky and find a wrecked chassis on ebay with engine. I found one there.