Meadowgirl14

98' Subaru Forester Overheating & No Heat!!
Please help b/c I can't afford for the mechanic to keep guessing! :( Had thermostat replaced yesterday and was still severly overheating within a mile of leaving the shop. I live in the middle of nowhere so don't have a choice of service centers and need these guys to get it right. Here's all the info I can think of to help:
1. Car does not overheat idling and half the time the heat is working when initially cranked in the morning then stops being hot down the road.
2. Coolant is full and should be no air pockets.
3. Resevoir was full of overflow when I got home, but coolant wasn't hot and level went down after it had set for a while.
4. Have had steam coming from hood when I've pulled over to turn it off when its overheated. No smoke.
5. Radiator is not leaking and is only 2 years old.
6. Top hose was hot but bottom hose was cold.

I'm probabaly forgetting things but feel free to ask. I can tell you that I need a new coil b/c it was misfiring on occasion but then this suddenly happened and figured better wait to see before investing...I'm aware head gaskets are worse case scenario but I really don't think that is it. I mentioned possible clogged heater core to mechanic but he brushed that off. Could it be water pump? Please help b/c I can't afford for these guys to keep guessing!! Thanks!

adc

Sounds like the T-Stat. Its not unusual for a new thermostat to fail. Is it a genuine Subaru one?

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AlphaMikeFoxtrot

I would say if it's within your means pull the thermostat out & see it it'll open when boiled in water, if not, there's your answer.

Meadowgirl14

Thread Starter

So just picked up from shop again b/c they have no solution and therefore think its the head gaskets but I'm still not completely convinced. They checked thermostat and apparently its good. They let it idle for quite a while and no overheating. I think they're at a loss and ,funny enough, checked (and printed out for me) an entry off of some forum they felt was similar to my problem and pointing at the head gaskets. I just don't feel like enough syptoms sound right but maybe there's so many varying symptoms that I'm wrong.

One of my biggest issues is that almost everything I've read about symptoms of bad head gaskets talks about coolant in resevoir bubbling/being hot when it overheats. But after overheating severely on the way home (living in the mountains...good for coasting downhill but gotta climb to get back home!), coolant in resevoir, which was 3/4 full was not bubbling and felt as though no heat was coming off of it so???? Thanks for all your help!

PS. So just ran down the road to an errand....overheated, of course. Resevoir didn't have time to get much in it (only 2 mile trip) but took cap off and tiniest bit of "steam" comes out but actual tank doesn't feel even warm and actual radiator cap not hot at all.

SplatSTi

Hmm Its either

1 Thermostat
2 Water pump
3 heater coil in cabin is blocked.

If it was the heads, you would have milky looking substance in your oil or oil in your coolant, which by the sounds of it, its not.

I had the same thing with my truck, I had to replace both the thermostat and water pump to correct the issue.

RadcomTxx

it does sound like the water pump. Hot coolant can rise out of the engine into the radiator, but isn't getting pumped through the engine. When idling, does temp gauge get to normal position without overheating? If so take the rad cap off, start it and let it idle up to temperature. Then look inside the rad to see if you can see the coolant flowing through the radiator. As a warning, the coolant may expand and overflow from the cap, so take precautions for that.

If it doesn't appear to be flowing, it would be best bet that it is the water pump. At idle not much heat is generated, so it may not overheat, but once under load much more heat is generated and without coolant flow, it overheats in 2 miles.

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funkymonkey1002

Is there any black residue in the plastic coolant overflow tank?

How many miles are on the car? Has the timing belt been changed? If so has the water pump ever been changed?

If you let it fully warm up at idle, does it ever overheat? When it gets up to normal temp on the gauge are both the top and bottom hoses hot or is the lower one cold? You might want to try running it with the t-stat completely removed and see how it behaves.

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Meadowgirl14

Thread Starter

Thanks for all the input. Frankly, I was so fed up yesterday that I didn't even fool with it, but today I'm headed home to double check all you've said before heading back to the shop Monday.
-I don't think there was anything wrong visually with coolant and shop made no mention of seeing anything wrong with it.
-car can idle forever without overheating!
-no matter what, the TOP hose is HOT, and the BOTTOM one is cold.
-148,000 miles, timing belt has been replaced, not sure about water pump.
-Had already mentioned the heater core possibly being blocked and, for whatever reason, mechanic didn't think it was that.
-Will definitely go home and carefully see if i can see coolant flowing through radiator!! I really get the feeling its not and definitely overheats that quickly under load.
Thanks for all the ideas!!.....starting to see a little ray of hope its not the HG. :)

adc

I doubt its the heater core..that won't make the engine overheat.

I would remove the t-stat first. and see if its that.

But I really suspect the water pump..its not pushing enough hot water.

Now understand if you remove the T-Stat the overheating may go away even with a bad water pump because of natural circulation. If you remove the T-Stat and the car does not overheat and the heat inside the car is still low it is very likely the Pump.

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rsay777

A 2 year old radiator shouldn't have any blockage but I would at least add it the list of culprits.