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Registered
1998 Forester Auto
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49 Posts
Discussion Starter · #1 ·
Hey all,

Having some issues with my '98 foz. I've done some work myself on the car but don't have a huge amount of technical knowledge.

Symptoms:

a) The interior heater doesn't work -- blows cold air.
b) The temperature gauge shows it running super hot.

I checked the coolant level this morning -- plenty of coolant. The overflow tank was full well above the "Full" line.

The radiator was replaced about three years ago, so that was the last time I changed the coolant.

Not sure where I should start. What might be causing this? What can I check?

Thanks!

Mike
 

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Premium Member
2019 Crosstrek 2018 Forester XT
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15,021 Posts
Is the radiator full?

Possible causes...clogged radiator
Bad water pump
Bad T-Stat

Possible bad Head Gaskets

Is the top hose hot and the lower hose cold? That indicates no flow.
 

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2014 Forester Limited CVT
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90 Posts
Two things-

Thermostat, not likely. Should be a fail open stat. If a t'stat fails closed, it does more than run hot- it will ERUPT!

Partially blocked radiator- very likely. Don't let the other stuff fool you, you most likely need a radiator. Or one hell of a power flush!

I have found that with a blocked radiator temp goes up with speed. Drove me crazy for a while....faster, more air through the coil, should be cooler right?
 

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Registered
1998 Forester Auto
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49 Posts
Discussion Starter · #4 ·
Hmm, OK, thanks. Will check radiator fluid level today at lunch, and hose temp tonight when I drive again.

Temp may go up with speed, I'm not sure... will see.

How can I check whether the radiator is blocked? I just replaced it a couple of years ago -- can it get blocked in that short a time?
 

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2014 Forester Limited CVT
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90 Posts
See adc post above, feel the hoses in and out. Both should be hot.
Sorry, but yeah in an older car a radiator can get gunked up in 3 years. Many reasons why, but I think yours may be partially, usually it it's the bottom tubes and up.
I'm not an auto mechanic, lol, just someone who has dealt with older cars and had the exact same symptoms once.
 

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Premium Member
2019 Crosstrek 2018 Forester XT
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15,021 Posts
Are you using a Dex-Cool type antifreeze
 

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Registered
1998 Forester Auto
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49 Posts
Discussion Starter · #8 ·
I assume if I have to ask what that is, I'm probably not using it?

I just checked the coolant level on my lunch break -- turns out it looks like I'm low on coolant. When I checked earlier the engine was hot, so I guess when it cools down the level goes down too.

So I guess the first thing to try is to add more coolant.
 

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Premium Member
2019 Crosstrek 2018 Forester XT
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15,021 Posts
I assume if I have to ask what that is, I'm probably not using it?

I just checked the coolant level on my lunch break -- turns out it looks like I'm low on coolant. When I checked earlier the engine was hot, so I guess when it cools down the level goes down too.

So I guess the first thing to try is to add more coolant.
Just make sure the radiator is filled (removing the cap). You can't tell of the radiator is full by checking the overflow bottle.
 

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1999 Forester auto
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118 Posts
Low coolant = hot running motor and no fluid passing thru the heater core, which means the air doesn't get warmed up.

Define super hot. It's a critical issue with Sub's and all other aluminum block motors. Cast iron can take heat, aluminum just goes soft and it's toast.

Therefore, define "super hot" because it's now the priority issue.
 

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1998 Forester S 4EAT
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574 Posts
Could it also be that the system isn't fully purged of air? Usually no heat would mean that the air is trapped in the heater core.
 

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2002 "Hulk" SF MT
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18 Posts
Check timing belt idler pulley. if the hydraulic seal goes on the tensioner part of the pulley your timing belt will be tight enough to run your engine but not tight enough to spin the water pump. the pump has a smooth pulley that is run by the back of the belt, not the toothed side.
 

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1998 Forester Auto
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49 Posts
Discussion Starter · #13 ·
Thanks for all the suggestions.

Checked out all those things. Timing belt pulley is fine. Refilled the radiator, burped it, filled it some more.

Ran better for a while (i.e. heater working, temp normal) but after about 15 minutes, the temp goes to the end of the scale again.

So by "super hot" I mean the needle is off the end of the gauge scale.

Reading around and speaking to a mechanic my suspicion now is a bad head gasket. The coolant overflow bottle is has black residue in it and smells like oil, not like coolant. When I refilled the radiator and drove it a bit, I let the engine cool, checked again and the coolant level was low again.

I'm off work now for a week or so, so it's sitting until I can take it to my garage and find out how much damage has been done.
 

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2014 Forester Premium CVT
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7 Posts
I just went through this very problem with my 1999 Outback Limited with 180,000 miles. All the same symptoms, mine was a blown head gasket. Dealer wanted minimum of $2,400 for the gasket and a lot more if the heads were cracked or warped. My solution.....I just bought a 2014 Forester Premium CVT.
Lov'n it so far (2 weeks), good luck!
 
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