For about the last 6 months, my wife has been loosing about 2 or 3 cups of coolant a month in her daily driver 03 Forester X. There's no leaks that I can find and there's never any leaking showing under the car. Does anyone have an idea as to what's causing this and where the disappearing coolant is going? The car never overheats and the engine runs fine.
Constant minimal coolant loss
- Thread starter jmacmaster
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That seems like too much coolant loss in too short a time frame to me. I'm suspicious of an internal coolant leak into the oil sump. Have an oil analysis done with a note to pay particular attention to the presence of glycol. If present, you've likely got a problematic head gasket or perhaps an intake manifild gasket. If your lead reading is high on a used oil analysis, babbit (bearing) corrosion has already begun. Antifreeze is particularly corrosive to the lead content of bearing inserts. Since I flushed and refilled my Sonata V6's cooling system 18 months ago, I might be down one quart, total, in that time frame. If my math is right, that's less than 2 oz./month compared to your 16 - 24 oz./month.
I bought an 05 Forester XT some six months ago. Almost immediately I noticed that it was slowly losing coolant so I carefully measured what I replaced. After 0.5 liters exactly, back to the dealer. They kept the thing all day and told me there was nothing leaking anywhere. After another 0.3 liters, back I went. Another all day session with a pressure test, again was told nothing found.
I had searched very closely myself and discovered some possible evidence of leakage under the pressure cap, but it was only faint white stains like it might have been evaporated coolant residue. Stuck the service writers head twice under the hood to show him but they weren't buying my theory. Finally in desperation I emailed SOA but they said to take it to the dealer. Then I wiggled and twisted every hose and clamp I could find. The leak immediately stopped and it has used no coolant in four months.
This doesn't help you much but it sure solved my problem, I think. From the Subaru forums, the head gasket leak was endemic on 2.5 EAT engines until mid-2002. It then supposedly got a factory fix. The leak apparently did not allow coolant into engine internals but leaked externally, even if only slowly. I did an oil analysis on mine just to be sure and there probably was never any in my oil.
I had searched very closely myself and discovered some possible evidence of leakage under the pressure cap, but it was only faint white stains like it might have been evaporated coolant residue. Stuck the service writers head twice under the hood to show him but they weren't buying my theory. Finally in desperation I emailed SOA but they said to take it to the dealer. Then I wiggled and twisted every hose and clamp I could find. The leak immediately stopped and it has used no coolant in four months.
This doesn't help you much but it sure solved my problem, I think. From the Subaru forums, the head gasket leak was endemic on 2.5 EAT engines until mid-2002. It then supposedly got a factory fix. The leak apparently did not allow coolant into engine internals but leaked externally, even if only slowly. I did an oil analysis on mine just to be sure and there probably was never any in my oil.
I had a similar problem with my wifes Cherokee. It started loosing a little coolant, so I fired off an oil sample to Blackstone. It showed no coolant in the oil at all. So I started doing some underhood detective work and found a slight leak in the overflow tank, around back and out of sight. It would drip a little when parked after running but dried up a short time later.
To make sure you don't have an internal leak I would suggest a UOA. It will at least prove/disprove the head gasket idea.
To make sure you don't have an internal leak I would suggest a UOA. It will at least prove/disprove the head gasket idea.
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