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1999 FORESTER L
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117 Posts
Discussion Starter · #1 ·
:icon_frown: I just replaced the HG with a set of COMETIC BRANDED HG and a New Radiator, Iridium Plugs, Air Filter, Oil Filter & Fluid, Tranny Filter & Fluid, All Seals & Gaskets, Water Pump, Thermostat & Seal, Gas Filter, Replaced Coolant. According to the mechanic the heads were not warped, just needed some cleaning. There are no leaks anywhere. When the car is parked with the motor running the temp gauge is in the middle. When I start driving is fine and until about 10-15 of constant driving the gauge goes up to the red and back to the middle, then up again and back & forth. After driving for about 20 minutes the gauge stays in the red. Now here is the funny part, THERE IS NO COOLANT leaking anywhere or the reserve tank overflowing, nothing! Can it be a BAD TEMP SENSOR? Sending false reading to the gauge? Please help I don't know what to do next.:icon_mad:
 

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1999 FORESTER L
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117 Posts
Discussion Starter · #3 ·
How do I get rid of that air in the system?
 

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84 Posts
How do I get rid of that air in the system?
Make sure the Thermostat is OEM. Aftermarket one has different specs.

Fill coolant to the radiator with the car running?

Thats the proper method of any car. Then you wait till the Thermostat opens, add some more, cap it, go for a drive, repeat.

Putting the coolant in slowly with the radiator vent open is fine.
 

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1999 FORESTER L
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117 Posts
Discussion Starter · #5 ·
I am going to try that and see what happens. Thanks for your advise guys.
 

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1999 Forester L
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29 Posts
My car did the same thing. It was the T-stat. I agree with the post above. Go to Subaru and get a OEM. Aftermarket ones don't work. They're totally different. Good Luck
 

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04 Forester X, MT
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1,039 Posts
when you fill it, be sure the front of the car is higher than the rear (on ramps or incline) to help the air come out to the highest point.
 

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1999 FORESTER L
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117 Posts
Discussion Starter · #8 ·
Well, I did the OEM thermostat install and it does the same thing, but as the car sits parked with the motor running the TEMP gauge is dead smack CENTER, right in the middle and it does not move until I start driving, after about 15-20 minutes of constant driving there goes the gauge right into the red zone. Someone said that it maybe a bad tensioner on the timing belt, since it turns the BRAND NEW water pump. if you rev the engine while in park after the car has been idling for about two hours the temp gauge goes up a little too. Very weird, the car can be parked and the motor running for 3-6 hours and the needle does not move at all. Please help I want to rule out a defective water pump. Any ideas anyone?
 

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2004 2.0 XT MT
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67 Posts
- My first approach would be to try to establish whether the engine is really running hot or if it's a sensor/gauge thing. Does the radiator hoses feel noticeably hotter when the gauge is in the red?
- Does the Forester temp gauge have a temperature compensation board? If it has, and it is broken, the gauge will fluctuate more.
 

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03X MT
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846 Posts
when the guage is showing hot is coolant being blown out of the expansion bottle? assuming it was at proper level b4?
 

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2006 Forester XT Limited 5 Speed Manual
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524 Posts
I had a similar probelm with my 89 Dodge truck with the oil pressure. I had the filter, pump, pick-up screen replaced, still showed low to no pressure. Pulled the valve cover to verify that oil was actually getting to the top of the engine and it was good. Finally replaced the sensor and that fixed it.

Have you replaced your temp sensor yet? If you have spent all this money on water pump, guage, and what else, than look to the simplest solution first....
 

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1999 FORESTER L
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117 Posts
Discussion Starter · #12 ·
Temp Sensor,....hummm!!!

I did notice that there is no coolant coming out from the overflow tank. But, why would I smell coolant up front by the radiator and overflow tank area? It does not hurt to buy the Temp Sensor anyway, since the car is 11 years old. Also the check engine light came on yesterday, a diagnostic test revealed that my 02 sensor on bank 1, Sensor 1 is bad or not ready. Would that cause the engine to overheat? :icon_frown:
 

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1999 FORESTER L
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117 Posts
Discussion Starter · #13 ·
when the guage is showing hot is coolant being blown out of the expansion bottle? assuming it was at proper level b4?
No there is no coolant blowing out from the expansion bottle, but you can smell coolant heating up from the bottle and smoke too.
 

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Perhaps try a new radiator cap.

Double-check to make sure that the piping system for the overflow coolant tank is not clogged.

Is the coolant at the correct strength?

Maybe a bad coolant temp sender?
 

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1999 FORESTER L
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117 Posts
Discussion Starter · #15 ·
I had the coolant system bled with a Snap-on machine that bleeds air out the system, the car still overheats. I have no choice but to take it to the dealer. It's a very weird situation, the car can sit parked with the engine running for 4-6 hours and the needle would not even move! How can I rule out a BAD waterpump?
 

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1999 FORESTER L
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117 Posts
Discussion Starter · #16 ·
Perhaps try a new radiator cap.

Double-check to make sure that the piping system for the overflow coolant tank is not clogged.

Is the coolant at the correct strength?

Maybe a bad coolant temp sender?
Yeah it has a NEW radiator cap, but it's not OEM Will pick one up tommorrow.
 

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1999 FORESTER L
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117 Posts
Discussion Starter · #17 · (Edited)
I Found out why my SF was overheating all this time!



This is why my SF was overheating, so now for the FIX!
 

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2010 Forester
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173 Posts
Nice to see that you've found the culprit. Did somebody dump sugar in your coolant? Are you going to flush the entire system in addition to replacing the thermostat?
 

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1999 FORESTER L
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117 Posts
Discussion Starter · #19 ·
I am not sure what it is, but the gunk was blocking the passages of the heads. I am going to flush it for several hours and see if I can get ALL of it out before I put in the NEW BLUE COOLANT from Subaru.
I tried to contact the previous owner to see if he can tell me what it is. Nothing yet.
 

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2010 Forester
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173 Posts
Well at least if you can get all that crap out of the coolant passages it should run like a new car with all the other work you put into it.
 
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