so with cooler weather coming the mornings have been a bit on the chilly side lately. enough so that I have turned on the defroster a couple of times to clear early morning fog... only problem is, the car seems to be creating it's own fog..

 

2002 Forester with over 220K on the clock... I can actually see a light vapor blowing across the inside of the windshield when I use the defrost setting.

 

If this is a heater core failing, I want to try to get it fixed before the real cold weather sets in.

 

I know it is not an easy job to do, but if it needs doing, I would rather do it now, with warmer temps than later in the cold.

does it smell like coolant?

 

if the car has a cabin air filter, could it be wet with condensation? drain tube clogged?

my sniffer isn't as good as it used to be (too many years as a smoker) so I cant really tell what it smells like.

 

it only does this in defrost mode and there is a slight film forming on the glass down low.

 

I have run the AC and have seen the condensation puddle under the car - but that does not rule out a partial clog (as in not draining completely)...

Not sure about cabin air filter, however

If there is a coolant leak, checking the upper radiator hose and recovery tank once per day before the first drive should give an answer. Note do not open the radiator cap while doing this checking, unless you are low on coolant in the upper hose and need to add some.

Start by cleaning the glass. Dirty glass will be much more likely to collect condensation. RainX makes an anti-fog product that works very well, that might be worth a try.

 

 

Heater cores almost always fail more catastrophically than that, leaving a puddle on the floor, reeking of antifreeze. I suppose it's not impossible to have a tiny pinhole that's just introducing some moisture into the system.

+1 to clean the windshield and is the A/C working when defrost mode is on?

Is the A/C working well?

 

if it was an coolant related leak (anywhere in the system - heater core or otherwise), it should show coolant loss in the cooling/radiator/engine - and eventually overheating. 

Yes, AC worked pretty darn well when it was 97 degrees and about 70% humidity (air you could wear)

 

I need to pull the floor mats and make sure the carpet is dry...

 

does the 2002 Forester have a cabin air filter? If it does, that is something else I can check.

not positive ; some early 2000 soobs were cabin filter 'capable' I think but may not have been delivered with it installed - it was an option maybe?

Very slow leak could be just barely enough to make some steam.

Try some Subaru coolant conditioner?

My 2002 Forester came equipped with a cabin-air filter-box.

But the box was empty, with no filter-media installed.

The box is under the glove-compartment, and has two removable rubber 'doors' on the bottom, each held closed by a couple of metal clips.

it has a bottle of the coolant conditioner in the system - it was added when I did the timing belt/water pump/etc.

 

My 2002 Forester came equipped with a cabin-air filter-box.

But the box was empty, with no filter-media installed.

The box is under the glove-compartment, and has two removable rubber 'doors' on the bottom, each held closed by a couple of metal clips.

 

Thank you for the information.

dig around at www.cars101.com for cabin filter instructions.

Yea, cabin air filter could have been added as an accessory. The accessory came with a sticker to put in the driver's door opening (typically near the VIN sticker, sometimes near the dash), that says it is equipped. But only way to tell for sure, is to check.

ok, Thanks for the info regarding the cabin air filter, guys - will be checking into that this weekend.

 

In the meantime - coolant overflow bottle is a bit low - not super concerning as yet, but will be keeping an eye on things. Upper radiator hose feels full..

have not had a chance to pull the floor mats yet (super busy with a major project for a big show coming up soon - so much to do, so little time kind of thing) but will do so this weekend.

check inside the radiator for coolant level too.

 

I also put 2 small zip ties on the little overflow tube at the nipple on the rad's neck - just to make sure air isn't pulled in, instead of coolant.(likely unrelated to your symptoms)