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Discussion Starter #1
Issue:
My Outback is having issues staying cool and not overheating when I drive it for more than 10 minutes.

Symptoms:
  • After driving for 10+ min, my temp gauge on the dashboard stays at the hottest position
  • Only cold air blows out my vents, no hot air even though the car is running hot
  • I'm not 100% sure, but I think the engine fans sometimes don't turn on when it gets too hot
  • Sometimes there is no issue, or the issue will resolve itself after I've been driving and it returns to a normal temp
What I've tried:
I installed a new thermostat 3/31/13 and replaced the coolant. No change.

Thanks for any help!!
 

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Is the top hose hot and the lower just warm?
System "burped" properly?
What T stat, Suby's are picky?
Last time T belt and water pump replaced.

O.
 

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I'm not 100% sure, but I think the engine fans sometimes don't turn on when it gets too hot
Fans (or at least one) should come even before the gauge starts to visibly climb. It would helpful to know with more certainty whether or not this is happening.

Is there any other signs related to overheating, such as the level of coolant in the external reservoir is very high or overflowing? Are there bubbles coming up in the coolant reservoir?

Have you rechecked the coolant level in the radiator itself, and in the external reservoir?

Lack of heat from the heater vents means the coolant in the heater core is probably cold (i.e., not hot). That could be due to air in the heater core (air in the cooling system), or poor circulation of the engine coolant. (More likely as the temperature gauge is high as well.) It could also be due to a blocked heater core, but this would mean cooler air pretty well all the time.

Air pockets in the cooling system could be due to a head gasket leak (there's a whole sub-forum on this here) and although that's not a common problem with the 2.2 engine, it's not unknown to happen.

Poor circulation through the heater core and the apparent overheating could be due to a failing water pump.

Also the pump is driven by the timing belt which has to be changed periodically. What's the mileage on the car and on the belt?

Did you install a genuine Subaru thermostat, or another brand? (Subaru stats can go in only one way; some others can be installed backwards -- not good. Also, some aftermarket stats don't work well in the Subaru boxer engine even when installed in the right direction.)
 

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Discussion Starter #4
Is the top hose hot and the lower just warm?
System "burped" properly?
What T stat, Suby's are picky?
Last time T belt and water pump replaced.
Will need to check the temp of the hoses next time it happens, I know the top has been hot. I bought a Stant thermostat (14147) from Advanced Auto Parts, which they said was original equipment. I put it in with the coil-looking end facing the engine / not sticking out. Timing belt hasn't been replacing in the 40k+. Water pump I replaced in the last 10k or 20k.


Is there any other signs related to overheating, such as the level of coolant in the external reservoir is very high or overflowing? Are there bubbles coming up in the coolant reservoir?
No, the coolant in the external isn't high or overflowing. There was one time before i replaced the thermostat where i saw it above the full line, but I pulled the car over, turned it off, checked things out, started it back up, and by the time i got to the auto store, it was empty.

Have you rechecked the coolant level in the radiator itself, and in the external reservoir?
According to the shop manual I have, there should be 6.3q in the system? The one I bought at the auto store was 3.something quarts, but the manual said not to fill the external res past the low mark, which I've been doing, but it's still not even finished the 3q.

Lack of heat from the heater vents means the coolant in the heater core is probably cold (i.e., not hot). That could be due to air in the heater core (air in the cooling system), or poor circulation of the engine coolant. (More likely as the temperature gauge is high as well.) It could also be due to a blocked heater core, but this would mean cooler air pretty well all the time.
I don't think it's that then because I sometime get hot air.

Also the pump is driven by the timing belt which has to be changed periodically. What's the mileage on the car and on the belt?
Car is at 199k and i bought it at 158k. Haven't replaced the belt since I've owned it and not sure when it was replaced before 158k.

Did you install a genuine Subaru thermostat, or another brand? (Subaru stats can go in only one way; some others can be installed backwards -- not good. Also, some aftermarket stats don't work well in the Subaru boxer engine even when installed in the right direction.)
Stant (14147), which the auto store said was original equipment for the 96 2.2

I'll keep an eye out for your other questions next time it spikes, thanks for any thoughts based on my responses.
 

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The best Stant is #48457. An exact copy of the Suby unit.
You can either replace the one you have with this or a genuine Suby unit. Then you'll know its not the T stat acting up (even though a new unit).
If not the T stat, then it is the pump.
Use the many T belt refs for replacement.
You are due for a T belt soon, so you might as well replace it, all the idlers,tighten screws on back of the oil pump, replacing the o ring back there and you won't have to go back in there for another 100K.
The importexperts on E bay have a good kit.
Refs to fsm :www.main.experiencetherave.com - /subaru_manual_scans/

O.
 

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According to the shop manual I have, there should be 6.3q in the system? The one I bought at the auto store was 3.something quarts, but the manual said not to fill the external res past the low mark, which I've been doing, but it's still not even finished the 3q.
Earlier you said that you changed the thermostat and coolant. If the system has 6.3 qt in it, then it should have taken something close to 5 or 6 qts to refill the engine block and radiator. The engine block and radiator have to be filled separately from the external reservoir.

Also, I don't know which service manual you are using, but when the engine is cold, the coolant in the external reservoir should be filled to the FULL mark.

There was one time before i replaced the thermostat where i saw it above the full line, but I pulled the car over, turned it off, checked things out, started it back up, and by the time i got to the auto store, it was empty.
The reservoir should never end up empty if the system is filled and operating properly.

While I might be misunderstanding some of the comments, my impression is that the engine/radiator might not be properly filled and that is leading to the overheating and poor heater output.
 

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^+1
You fill the block through the upper radiator hose.
Open bleeder screw, then fill radiator.
Let idle until no more can be added.
Close bleeder and cap.
System will pull from reservoir until it reaches capacity.

O.
 

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Discussion Starter #9
The reservoir should never end up empty if the system is filled and operating properly.
Good to know, I've never been sure and have never read anywhere what it is supposed to be. I'll keep adding and assume that's the problem for now and see if it fixes it.

When I replaced the thermostat, I
  1. opened the drain plug
  2. removed the bolts on the lower hose
  3. I'm assuming that emptied out all of the 6.3 quarts
  4. replaced the t-stat
  5. put coolant into the radiator until it wouldn't take any more
  6. turned the engine on and let it idle for a bit
  7. turned off the engine and put coolant into the external to the lower line
  8. of the 1 gal / 4 quarts I bought, still haven't finished adding it all to the system, which would mean even after I did it's still 2 quarts short
The manual I used never mentioned anything about adding coolant to the engine block though??

Manual I'm using: http://i.imgur.com/g76RA2T.jpg
Cooling system needs 6.3 quarts: http://i.imgur.com/tj5fW2L.jpg
Thermostat instructions pt 1: http://i.imgur.com/3J3jiWy.jpg
Thermostat instructions pt 2: http://i.imgur.com/Ckdl6sy.jpg
(Sorry, I forgot to include the instructions for refilling coolant from the first section of the book)
 

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When you pour coolant into the radiator it will fill the radiator and then begin to fill the block through the upper radiator hose (when the level in the radiator is high enough to flow coolant into the hose). However, if the coolant is poured in too fast, a lot of air will be trapped in the block, and possibly the radiator core as well. It's important to add the coolant very slowly so that air in the block can work it's way up through the internal passages and upper radiator hose, and exit via the radiator cap neck.

If you replaced the thermostat, then both the block and radiator were pretty well emptied and so, yes, it should have taken all of the gallon of coolant plus more to fill the engine block and radiator, let alone also fill the external reservoir. If there's less than 4 qts in the system, then that could well be the cause of the overheating and lack of heat from the heater.

By the way, after the engine cooled in #7 above, did you recheck or top-up the level of coolant in the radiator?

(Also, just to be sure, is the coolant you are adding a "pre-mixed, 50/50" type, or is it the type that you have to add water to bring to the correct concentration?
 

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Discussion Starter #11
By the way, after the engine cooled in #7 above, did you recheck or top-up the level of coolant in the radiator?

(Also, just to be sure, is the coolant you are adding a "pre-mixed, 50/50" type, or is it the type that you have to add water to bring to the correct concentration?
I didn't recheck because the instructions in the manual never said to. When I originally put coolant in the radiator, once it stopped filling with the engine off, then I ran the engine, and it took a while (3+ min prob) for the remaining amount still in the funnel to go through the radiator. Normal?

Yes, it was pre-mixed 50-50.
 

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Yes normal -- when the thermostat opens the pump draws coolant from the radiator (especially if the block isn't full) so the level suddenly goes down. This dropped the level in the funnel, but if the funnel emptied, more probably could have been added.

After the engine is stopped for a while and the coolant in the engine cools, it contracts in volume. This contraction has to be replaced by coolant, and as the funnel was already emptied, there was no coolant to make up the space. In other words, it's possible that the engine and radiator were not full, as they should be.

Normally, in a properly filled and operating cooling system, when the engine is cold, the radiator should be full to the height of the overflow hose on the radiator cap neck, and the level in the external reservoir should be at the Full mark. When the engine is hot, the level in the reservoir will go up by an inch or so (but not high enough to reach the cap) and then fall back to the Full mark when the engine cools again.

Any deviation from this pattern sometimes can be a sign of a system that isn't working properly.

The photo attachment shows that the 96 2.2 engine with front wheel drive (not AWD) will use 6.3 qts, while the same engine used with 4WD needs 7.4 qts. So I presume yours is a FWD model, otherwise it would need even more for a full change.
 

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Discussion Starter #13
Thanks for all the great info, from everyone. Very informative.

I've been adding coolant via the external res to get it back to where it's supposed to be. It seems to be helping, and I'm up to a little over 4 quarts total now. I'm assuming this method is the same as if I added it to the radiator directly while the engine is idling?

The photo attachment shows that the 96 2.2 engine with front wheel drive (not AWD) will use 6.3 qts, while the same engine used with 4WD needs 7.4 qts. So I presume yours is a FWD model, otherwise it would need even more for a full change.
I think that's just for AWD for years only up to 1994, right?
 

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You're right -- the 96 is 6.3 qts. I misread it.

It can take some time for the system to draw coolant in from the reservoir to fill an under-filled system. This is because it has to develop a vacuum as the engine cools, and only then will it draw coolant from the reservoir. But it will do this only until the negative vacuum pressure reaches the level of the relief valve on the rad cap. So it might have drawn some coolant back in, but it might not be anywhere near what is needed to fill the cooling system.

When you know the system is under-filled, it's better to fill it through the radiator. Then the normal expansion/contraction of the coolant will maintain the full level in the engine.

Wait until the engine is cooled down, remove the rad cap and slowly fill the radiator till it's up to the overflow hose. Replace the cap, and then make sure that the level in the external reservoir is at the full mark.

Keep doing this after each drive cycle until you find that when the rad cap is taken off, the level inside is up to the overflow hose outlet (where the hose is connected). After this, if the cooling system is losing fluid, each time the car is cooled down, the level in the reservoir will be lower than the last time (the coolant lost is being replaced by coolant from the reservoir) and that's your signal that there could be a problem. But for this to work, it has to start with a cooling system that is full and without any residual air pockets.

Also, the hose to the reservoir must be clear of any debris inside (as should the bottom of the reservoir). It should be tight on the rad fitting and without any cracks that can let air in.
 

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......Also, the hose to the reservoir must be clear of any debris inside (as should the bottom of the reservoir). It should be tight on the rad fitting and without any cracks that can let air in.
There was a TSB on the radiator hose a while back. Just cut the end at a small angle so that it doesn't accidentally suck itself to the bottom of the reservoir and therefore not function properly.

I pray this is all your problem is.

O.
 

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Discussion Starter #16
Quick update: I was lucky it seems and just had an issue with the amount of coolant in the system. However, I agree that it's time for the water pump, timing belt, and a few other things in the area to probably be replaced, so I'm going to look into that in the next few months.

Thanks to everyone who helped out with this, lots of great information to be had and very friendly and helpful forum members!!
 
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